annotate xml/en/docs/dev/development_guide.xml @ 1981:082724c57c38

Fixes in cycle section of the development guide. Field descriptions are improved and misspelled literal names are fixed.
author Roman Arutyunyan <arut@nginx.com>
date Thu, 27 Apr 2017 18:11:49 +0300
parents 5718cf42be55
children 28ee7ab54a90
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1 <?xml version="1.0"?>
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2
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3 <!--
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4 Copyright (C) Nginx, Inc.
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5 -->
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6
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7 <!DOCTYPE article SYSTEM "../../../../dtd/article.dtd">
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8
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9 <article name="Development guide"
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10 link="/en/docs/dev/development_guide.html"
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11 lang="en"
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12 rev="2">
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13
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14 <section name="Introduction" id="introduction">
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15
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16
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17 <section name="Code layout" id="code_layout">
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18
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19 <para>
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20 <list type="bullet">
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21 <listitem>
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22 <literal>auto</literal> — build scripts
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23 </listitem>
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24
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25 <listitem>
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26 <literal>src</literal>
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27
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28 <list type="bullet">
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29
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30 <listitem>
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31 <literal>core</literal> — basic types and functions — string, array, log,
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32 pool etc
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33 </listitem>
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34
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35 <listitem>
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36 <literal>event</literal> — event core
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37
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38 <list type="bullet">
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39
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40 <listitem>
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41 <literal>modules</literal> — event notification modules: epoll, kqueue,
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42 select etc
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43 </listitem>
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44
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45 </list>
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46
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47 </listitem>
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48
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49 <listitem>
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50 <literal>http</literal> — core HTTP module and common code
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51
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52 <list type="bullet">
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53
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54 <listitem>
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55 <literal>modules</literal> — other HTTP modules
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56 </listitem>
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57
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58 <listitem>
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59 <literal>v2</literal> — HTTPv2
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60 </listitem>
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61
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62 </list>
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63
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64 </listitem>
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65
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66 <listitem>
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67 <literal>mail</literal> — mail modules
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68 </listitem>
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69
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70 <listitem>
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71 <literal>os</literal> — platform-specific code
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72
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73 <list type="bullet">
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74
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75 <listitem>
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76 <literal>unix</literal>
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77 </listitem>
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78
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79 <listitem>
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80 <literal>win32</literal>
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81 </listitem>
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82
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83 </list>
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84
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85 </listitem>
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86
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87 <listitem>
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88 <literal>stream</literal> — stream modules
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89 </listitem>
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90
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91 </list>
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92
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93 </listitem>
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94
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95 </list>
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96 </para>
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97
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98 </section>
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99
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100
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101 <section name="Include files" id="include_files">
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102
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103 <para>
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104 Each nginx file should start with including the following two files:
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105 </para>
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106
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107
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108 <programlisting>
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109 #include &lt;ngx_config.h>
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110 #include &lt;ngx_core.h>
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111 </programlisting>
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112
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113 <para>
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114 In addition to that, HTTP code should include
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115 </para>
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116
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117
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118 <programlisting>
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119 #include &lt;ngx_http.h>
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120 </programlisting>
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121
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122 <para>
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123 Mail code should include
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124 </para>
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125
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126
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127 <programlisting>
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128 #include &lt;ngx_mail.h>
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129 </programlisting>
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130
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131 <para>
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132 Stream code should include
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133 </para>
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134
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135
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136 <programlisting>
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137 #include &lt;ngx_stream.h>
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138 </programlisting>
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139
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140 </section>
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141
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142
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143 <section name="Integers" id="integers">
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144
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145 <para>
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146 For general purpose, nginx code uses the following two integer types
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147 <literal>ngx_int_t</literal> and <literal>ngx_uint_t</literal> which are
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148 typedefs for <literal>intptr_t</literal> and <literal>uintptr_t</literal>.
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149 </para>
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150
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151 </section>
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152
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153
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154 <section name="Common return codes" id="common_return_codes">
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155
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156 <para>
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157 Most functions in nginx return the following codes:
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158 </para>
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159
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160 <para>
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161 <list type="bullet">
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162
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163 <listitem>
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164 <literal>NGX_OK</literal> — operation succeeded
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165 </listitem>
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166
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167 <listitem>
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168 <literal>NGX_ERROR</literal> — operation failed
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169 </listitem>
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170
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171 <listitem>
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172 <literal>NGX_AGAIN</literal> — operation incomplete, function should be called
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173 again
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174 </listitem>
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175
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176 <listitem>
1935
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177 <literal>NGX_DECLINED</literal> — operation rejected, for example, if disabled
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178 in configuration. This is never an error
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179 </listitem>
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180
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181 <listitem>
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182 <literal>NGX_BUSY</literal> — resource is not available
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183 </listitem>
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184
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185 <listitem>
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186 <literal>NGX_DONE</literal> — operation done or continued elsewhere.
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187 Also used as an alternative success code
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188 </listitem>
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189
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190 <listitem>
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191 <literal>NGX_ABORT</literal> — function was aborted.
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192 Also used as an alternative error code
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193 </listitem>
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194
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195 </list>
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196 </para>
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197
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198 </section>
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199
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200
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201 <section name="Error handling" id="error_handling">
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202
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203 <para>
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204 For getting the last system error code, the <literal>ngx_errno</literal> macro
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205 is available.
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206 It's mapped to <literal>errno</literal> on POSIX platforms and to
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207 <literal>GetLastError()</literal> call in Windows.
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208 For getting the last socket error number, the
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209 <literal>ngx_socket_errno</literal> macro is available.
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210 It's mapped to <literal>errno</literal> on POSIX systems as well,
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211 and to <literal>WSAGetLastError()</literal> call on Windows.
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212 For performance reasons the values of <literal>ngx_errno</literal> or
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213 <literal>ngx_socket_errno</literal> should not be accessed more than
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214 once in a row.
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215 The error value should be stored in a local variable of type
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216 <literal>ngx_err_t</literal> for using multiple times, if required.
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217 For setting errors, <literal>ngx_set_errno(errno)</literal> and
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218 <literal>ngx_set_socket_errno(errno)</literal> macros are available.
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219 </para>
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220
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221 <para>
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222 The values of <literal>ngx_errno</literal> or
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223 <literal>ngx_socket_errno</literal> can be passed to logging functions
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224 <literal>ngx_log_error()</literal> and <literal>ngx_log_debugX()</literal>, in
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225 which case system error text is added to the log message.
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226 </para>
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227
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228 <para>
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229 Example using <literal>ngx_errno</literal>:
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230 </para>
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231
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232
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233 <programlisting>
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234 void
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235 ngx_my_kill(ngx_pid_t pid, ngx_log_t *log, int signo)
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236 {
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237 ngx_err_t err;
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238
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239 if (kill(pid, signo) == -1) {
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240 err = ngx_errno;
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241
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242 ngx_log_error(NGX_LOG_ALERT, log, err, "kill(%P, %d) failed", pid, signo);
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243
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244 if (err == NGX_ESRCH) {
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245 return 2;
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246 }
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247
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248 return 1;
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249 }
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250
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251 return 0;
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252 }
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253 </programlisting>
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254
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255 </section>
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256
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257
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258 </section>
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259
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260
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261 <section name="Strings" id="strings">
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262
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263
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264 <section name="Overview" id="overview">
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265
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266 <para>
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267 For C strings, nginx code uses unsigned character type pointer
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268 <literal>u_char *</literal>.
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269 </para>
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270
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271 <para>
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272 The nginx string type <literal>ngx_str_t</literal> is defined as follows:
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273 </para>
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274
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275
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276 <programlisting>
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277 typedef struct {
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278 size_t len;
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279 u_char *data;
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280 } ngx_str_t;
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281 </programlisting>
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282
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283 <para>
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284 The <literal>len</literal> field holds the string length,
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285 <literal>data</literal> holds the string data.
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286 The string, held in <literal>ngx_str_t</literal>, may or may not be
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287 null-terminated after the <literal>len</literal> bytes.
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288 In most cases it’s not.
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289 However, in certain parts of code (for example, when parsing configuration),
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290 <literal>ngx_str_t</literal> objects are known to be null-terminated, and that
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291 knowledge is used to simplify string comparison and makes it easier to pass
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292 those strings to syscalls.
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293 </para>
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294
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295 <para>
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296 A number of string operations are provided in nginx.
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297 They are declared in <path>src/core/ngx_string.h</path>.
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298 Some of them are wrappers around standard C functions:
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299 </para>
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300
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301 <para>
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302 <list type="bullet">
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303
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304 <listitem>
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305 <literal>ngx_strcmp()</literal>
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306 </listitem>
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307
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308 <listitem>
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309 <literal>ngx_strncmp()</literal>
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310 </listitem>
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311
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312 <listitem>
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313 <literal>ngx_strstr()</literal>
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314 </listitem>
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315
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316 <listitem>
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317 <literal>ngx_strlen()</literal>
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318 </listitem>
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319
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320 <listitem>
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321 <literal>ngx_strchr()</literal>
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322 </listitem>
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323
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324 <listitem>
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325 <literal>ngx_memcmp()</literal>
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326 </listitem>
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327
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328 <listitem>
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329 <literal>ngx_memset()</literal>
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330 </listitem>
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331
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332 <listitem>
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333 <literal>ngx_memcpy()</literal>
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334 </listitem>
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335
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336 <listitem>
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337 <literal>ngx_memmove()</literal>
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338 </listitem>
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339
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340 </list>
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341
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342 </para>
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343
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344 <para>
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345 Some nginx-specific string functions:
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346 </para>
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347
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348 <para>
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349 <list type="bullet">
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350
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351 <listitem>
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352 <literal>ngx_memzero()</literal> fills memory with zeroes
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353 </listitem>
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354
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355 <listitem>
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356 <literal>ngx_cpymem()</literal> does the same as
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357 <literal>ngx_memcpy()</literal>, but returns the final destination address
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358 This one is handy for appending multiple strings in a row
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359 </listitem>
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360
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parents:
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361 <listitem>
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362 <literal>ngx_movemem()</literal> does the same as
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363 <literal>ngx_memmove()</literal>, but returns the final destination address.
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parents:
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364 </listitem>
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365
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366 <listitem>
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367 <literal>ngx_strlchr()</literal> searches for a character in a string,
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368 delimited by two pointers
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369 </listitem>
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370 </list>
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371 </para>
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372
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373 <para>
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374 Some case conversion and comparison functions:
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375 </para>
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376
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377 <para>
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378 <list type="bullet">
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379
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380 <listitem>
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381 <literal>ngx_tolower()</literal>
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382 </listitem>
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Vladimir Homutov <vl@nginx.com>
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383
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parents:
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384 <listitem>
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Vladimir Homutov <vl@nginx.com>
parents:
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385 <literal>ngx_toupper()</literal>
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parents:
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386 </listitem>
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Vladimir Homutov <vl@nginx.com>
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387
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parents:
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388 <listitem>
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Vladimir Homutov <vl@nginx.com>
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389 <literal>ngx_strlow()</literal>
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Vladimir Homutov <vl@nginx.com>
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390 </listitem>
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Vladimir Homutov <vl@nginx.com>
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391
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parents:
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392 <listitem>
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393 <literal>ngx_strcasecmp()</literal>
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Vladimir Homutov <vl@nginx.com>
parents:
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394 </listitem>
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Vladimir Homutov <vl@nginx.com>
parents:
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395
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Vladimir Homutov <vl@nginx.com>
parents:
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396 <listitem>
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397 <literal>ngx_strncasecmp()</literal>
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Vladimir Homutov <vl@nginx.com>
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398 </listitem>
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Vladimir Homutov <vl@nginx.com>
parents:
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399
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400 </list>
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parents:
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401 </para>
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Vladimir Homutov <vl@nginx.com>
parents:
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402
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parents:
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403 </section>
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Vladimir Homutov <vl@nginx.com>
parents:
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404
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Vladimir Homutov <vl@nginx.com>
parents:
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405
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Vladimir Homutov <vl@nginx.com>
parents:
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406 <section name="Formatting" id="formatting">
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407
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Vladimir Homutov <vl@nginx.com>
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408 <para>
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409 A number of formatting functions are provided by nginx. These functions support nginx-specific types:
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410 </para>
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Vladimir Homutov <vl@nginx.com>
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411
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
412
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Vladimir Homutov <vl@nginx.com>
parents:
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413 <para>
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Vladimir Homutov <vl@nginx.com>
parents:
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414 <list type="bullet">
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415
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parents:
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416 <listitem>
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parents:
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417 <literal>ngx_sprintf(buf, fmt, ...)</literal>
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418 </listitem>
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419
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parents:
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420 <listitem>
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421 <literal>ngx_snprintf(buf, max, fmt, ...)</literal>
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Vladimir Homutov <vl@nginx.com>
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422 </listitem>
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423
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424 <listitem>
1975
459a6f194fcf Fixed a typo.
Vladimir Homutov <vl@nginx.com>
parents: 1971
diff changeset
425 <literal>ngx_slprintf(buf, last, fmt, ...)</literal>
1899
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426 </listitem>
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427
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428 <listitem>
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429 <literal>ngx_vslprint(buf, last, fmt, args)</literal>
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diff changeset
430 </listitem>
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431
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diff changeset
432 <listitem>
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433 <literal>ngx_vsnprint(buf, max, fmt, args)</literal>
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Vladimir Homutov <vl@nginx.com>
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diff changeset
434 </listitem>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
435
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parents:
diff changeset
436 </list>
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parents:
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437 </para>
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Vladimir Homutov <vl@nginx.com>
parents:
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438
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439 <para>
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440 The full list of formatting options, supported by these functions, can be found
1915
8b7c3b0ef1a4 Semantically marked paths.
Vladimir Homutov <vl@nginx.com>
parents: 1914
diff changeset
441 in <path>src/core/ngx_string.c</path>. Some of them are:
1899
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442 </para>
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443
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parents:
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444
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Vladimir Homutov <vl@nginx.com>
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445 <programlisting>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
446 %O — off_t
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Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
447 %T — time_t
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
448 %z — size_t
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
449 %i — ngx_int_t
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
450 %p — void *
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
451 %V — ngx_str_t *
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
452 %s — u_char * (null-terminated)
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
453 %*s — size_t + u_char *
1899
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parents:
diff changeset
454 </programlisting>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
455
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
456 <para>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
457 The ‘u’ modifier makes most types unsigned, ‘X’/‘x’ convert output to hex.
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parents:
diff changeset
458 </para>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
459
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
460 <para>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
461 Example:
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
462
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
463 <programlisting>
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parents:
diff changeset
464 u_char buf[NGX_INT_T_LEN];
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parents:
diff changeset
465 size_t len;
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
466 ngx_int_t n;
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
467
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
468 /* set n here */
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parents:
diff changeset
469
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
470 len = ngx_sprintf(buf, "%ui", n) — buf;
1899
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parents:
diff changeset
471 </programlisting>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
472
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
473 </para>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
474
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
475 </section>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
476
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
477
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
478 <section name="Numeric conversion" id="numeric_conversion">
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
479
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
480 <para>
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Vladimir Homutov <vl@nginx.com>
parents:
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481 Several functions for numeric conversion are implemented in nginx:
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
482 </para>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
483
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
484 <para>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
485 <list type="bullet">
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
486
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parents:
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487 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
488 <literal>ngx_atoi(line, n)</literal> — converts a string of given length to a
1899
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parents:
diff changeset
489 positive integer of type <literal>ngx_int_t</literal>.
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parents:
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490 Returns <literal>NGX_ERROR</literal> on error
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Vladimir Homutov <vl@nginx.com>
parents:
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491 </listitem>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
492
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
493 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
494 <literal>ngx_atosz(line, n)</literal> — same for <literal>ssize_t</literal>
1899
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
495 type
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
496 </listitem>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
497
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
498 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
499 <literal>ngx_atoof(line, n)</literal> — same for <literal>off_t</literal>
1899
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parents:
diff changeset
500 type
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
501 </listitem>
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parents:
diff changeset
502
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parents:
diff changeset
503 <listitem>
1935
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Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
504 <literal>ngx_atotm(line, n)</literal> — same for <literal>time_t</literal>
1899
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parents:
diff changeset
505 type
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
506 </listitem>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
507
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
508 <listitem>
1935
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Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
509 <literal>ngx_atofp(line, n, point)</literal> — converts a fixed point floating
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
510 number of given length to a positive integer of type
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
511 <literal>ngx_int_t</literal>.
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
512 The result is shifted left by <literal>points</literal> decimal
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
513 positions. The string representation of the number is expected to have no more
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
514 than <literal>points</literal> fractional digits.
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parents:
diff changeset
515 Returns <literal>NGX_ERROR</literal> on error. For example,
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
516 <literal>ngx_atofp("10.5", 4, 2)</literal> returns <literal>1050</literal>
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parents:
diff changeset
517 </listitem>
b86cfece30c3 Added development guide.
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parents:
diff changeset
518
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
519 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
520 <literal>ngx_hextoi(line, n)</literal> — converts hexadecimal representation of
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
521 a positive integer to <literal>ngx_int_t</literal>. Returns
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
522 <literal>NGX_ERROR</literal> on error
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
523 </listitem>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
524
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
525 </list>
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parents:
diff changeset
526 </para>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
527
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parents:
diff changeset
528 </section>
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Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
529
1919
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
530 <section name="Regular expressions" id="regex">
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
531
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
532 <para>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
533 The regular expressions interface in nginx is a wrapper around
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
534 the <link url="http://www.pcre.org">PCRE</link>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
535 library.
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
536 The corresponding header file is <path>src/core/ngx_regex.h</path>.
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
537 </para>
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Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
538
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Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
539 <para>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
540 To use a regular expression for string matching, first, it needs to be
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
541 compiled, this is usually done at configuration phase.
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
542 Note that since PCRE support is optional, all code using the interface must
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
543 be protected by the surrounding <literal>NGX_PCRE</literal> macro:
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
544 <programlisting>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
545 #if (NGX_PCRE)
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
546 ngx_regex_t *re;
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
547 ngx_regex_compile_t rc;
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
548
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
549 u_char errstr[NGX_MAX_CONF_ERRSTR];
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
550
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
551 ngx_str_t value = ngx_string("message (\\d\\d\\d).*Codeword is '(?&lt;cw&gt;\\w+)'");
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
552
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
553 ngx_memzero(&amp;rc, sizeof(ngx_regex_compile_t));
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
554
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
555 rc.pattern = value;
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
556 rc.pool = cf->pool;
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
557 rc.err.len = NGX_MAX_CONF_ERRSTR;
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
558 rc.err.data = errstr;
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
559 /* rc.options are passed as is to pcre_compile() */
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
560
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
561 if (ngx_regex_compile(&amp;rc) != NGX_OK) {
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
562 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "%V", &amp;rc.err);
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
563 return NGX_CONF_ERROR;
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
564 }
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
565
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
566 re = rc.regex;
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
567 #endif
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
568 </programlisting>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
569 After successful compilation, <literal>ngx_regex_compile_t</literal> structure
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
570 fields <literal>captures</literal> and <literal>named_captures</literal>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
571 are filled with count of all and named captures respectively found in the
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
572 regular expression.
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
573 </para>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
574
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
575 <para>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
576 Later, the compiled regular expression may be used to match strings against it:
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
577 <programlisting>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
578 ngx_int_t n;
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
579 int captures[(1 + rc.captures) * 3];
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
580
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
581 ngx_str_t input = ngx_string("This is message 123. Codeword is 'foobar'.");
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
582
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
583 n = ngx_regex_exec(re, &amp;input, captures, (1 + rc.captures) * 3);
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
584 if (n >= 0) {
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
585 /* string matches expression */
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
586
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
587 } else if (n == NGX_REGEX_NO_MATCHED) {
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
588 /* no match was found */
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
589
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
590 } else {
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
591 /* some error */
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
592 ngx_log_error(NGX_LOG_ALERT, log, 0, ngx_regex_exec_n " failed: %i", n);
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
593 }
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
594 </programlisting>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
595 The arguments of <literal>ngx_regex_exec()</literal> are: the compiled regular
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
596 expression <literal>re</literal>, string to match <literal>s</literal>,
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
597 optional array of integers to hold found <literal>captures</literal>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
598 and its <literal>size</literal>.
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
599 The <literal>captures</literal> array size must be a multiple of three,
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
600 per requirements of the
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
601 <link url="http://www.pcre.org/original/doc/html/pcreapi.html">PCRE API</link>.
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
602 In the example, its size is calculated from a total number of captures plus
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
603 one for the matched string itself.
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
604 </para>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
605
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
606 <para>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
607 Now, if there are matches, captures may be accessed:
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
608 <programlisting>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
609 u_char *p;
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
610 size_t size;
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
611 ngx_str_t name, value;
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
612
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
613 /* all captures */
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
614 for (i = 0; i &lt; n * 2; i += 2) {
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
615 value.data = input.data + captures[i];
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
616 value.len = captures[i + 1] — captures[i];
1919
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
617 }
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
618
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
619 /* accessing named captures */
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
620
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
621 size = rc.name_size;
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
622 p = rc.names;
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
623
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
624 for (i = 0; i &lt; rc.named_captures; i++, p += size) {
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
625
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
626 /* capture name */
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
627 name.data = &amp;p[2];
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
628 name.len = ngx_strlen(name.data);
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
629
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
630 n = 2 * ((p[0] &lt;&lt; 8) + p[1]);
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
631
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
632 /* captured value */
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
633 value.data = &amp;input.data[captures[n]];
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
634 value.len = captures[n + 1] — captures[n];
1919
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
635 }
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
636 </programlisting>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
637 </para>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
638
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
639 <para>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
640 The <literal>ngx_regex_exec_array()</literal> function accepts the array of
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
641 <literal>ngx_regex_elt_t</literal> elements (which are just compiled regular
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
642 expressions with associated names), a string to match and a log.
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
643 The function will apply expressions from the array to the string until
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
644 the match is found or no more expressions are left.
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
645 The return value is <literal>NGX_OK</literal> in case of match and
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
646 <literal>NGX_DECLINED</literal> otherwise, or <literal>NGX_ERROR</literal>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
647 in case of error.
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
648 </para>
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
649
dcfb4f3ac8a7 Added the "Regular expressions" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1915
diff changeset
650 </section>
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
651
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
652 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
653
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
654
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
655 <section name="Containers" id="containers">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
656
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
657
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
658 <section name="Array" id="array">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
659
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
660 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
661 The nginx array type <literal>ngx_array_t</literal> is defined as follows
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
662 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
663
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
664
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
665 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
666 typedef struct {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
667 void *elts;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
668 ngx_uint_t nelts;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
669 size_t size;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
670 ngx_uint_t nalloc;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
671 ngx_pool_t *pool;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
672 } ngx_array_t;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
673 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
674
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
675 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
676 The elements of array are available through the <literal>elts</literal> field.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
677 The number of elements is held in the <literal>nelts</literal> field.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
678 The <literal>size</literal> field holds the size of a single element and is set
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
679 when initializing the array.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
680 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
681
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
682 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
683 An array can be created in a pool with the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
684 <literal>ngx_array_create(pool, n, size)</literal> call.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
685 An already allocated array object can be initialized with the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
686 <literal>ngx_array_init(array, pool, n, size)</literal> call.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
687 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
688
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
689
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
690 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
691 ngx_array_t *a, b;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
692
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
693 /* create an array of strings with preallocated memory for 10 elements */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
694 a = ngx_array_create(pool, 10, sizeof(ngx_str_t));
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
695
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
696 /* initialize string array for 10 elements */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
697 ngx_array_init(&amp;b, pool, 10, sizeof(ngx_str_t));
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
698 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
699
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
700 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
701 Adding elements to array are done with the following functions:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
702 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
703
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
704 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
705 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
706
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
707 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
708 <literal>ngx_array_push(a)</literal> adds one tail element and returns pointer
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
709 to it
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
710 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
711
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
712 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
713 <literal>ngx_array_push_n(a, n)</literal> adds <literal>n</literal> tail elements
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
714 and returns pointer to the first one
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
715 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
716
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
717 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
718 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
719
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
720 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
721 If currently allocated memory is not enough for new elements, a new memory for
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
722 elements is allocated and existing elements are copied to that memory.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
723 The new memory block is normally twice as large, as the existing one.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
724 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
725
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
726
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
727 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
728 s = ngx_array_push(a);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
729 ss = ngx_array_push_n(&amp;b, 3);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
730 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
731
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
732 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
733
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
734
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
735 <section name="List" id="list">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
736
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
737 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
738 List in nginx is a sequence of arrays, optimized for inserting a potentially
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
739 large number of items. The list type is defined as follows:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
740 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
741
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
742
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
743 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
744 typedef struct {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
745 ngx_list_part_t *last;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
746 ngx_list_part_t part;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
747 size_t size;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
748 ngx_uint_t nalloc;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
749 ngx_pool_t *pool;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
750 } ngx_list_t;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
751 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
752
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
753 <para>
1958
95a7e6eb5270 Fixed spelling.
Roman Arutyunyan <arut@nginx.com>
parents: 1939
diff changeset
754 The actual items are stored in list parts, defined as follows:
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
755 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
756
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
757
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
758 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
759 typedef struct ngx_list_part_s ngx_list_part_t;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
760
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
761 struct ngx_list_part_s {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
762 void *elts;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
763 ngx_uint_t nelts;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
764 ngx_list_part_t *next;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
765 };
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
766 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
767
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
768 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
769 Initially, a list must be initialized by calling
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
770 <literal>ngx_list_init(list, pool, n, size)</literal> or created by calling
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
771 <literal>ngx_list_create(pool, n, size)</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
772 Both functions receive the size of a single item and a number of items per list
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
773 part.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
774 The <literal>ngx_list_push(list)</literal> function is used to add an item to the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
775 list. Iterating over the items is done by direct accessing the list fields, as
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
776 seen in the example:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
777 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
778
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
779
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
780 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
781 ngx_str_t *v;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
782 ngx_uint_t i;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
783 ngx_list_t *list;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
784 ngx_list_part_t *part;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
785
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
786 list = ngx_list_create(pool, 100, sizeof(ngx_str_t));
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
787 if (list == NULL) { /* error */ }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
788
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
789 /* add items to the list */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
790
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
791 v = ngx_list_push(list);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
792 if (v == NULL) { /* error */ }
1936
8f996938fe23 Style: proper quotes usage.
Vladimir Homutov <vl@nginx.com>
parents: 1935
diff changeset
793 ngx_str_set(v, "foo");
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
794
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
795 v = ngx_list_push(list);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
796 if (v == NULL) { /* error */ }
1936
8f996938fe23 Style: proper quotes usage.
Vladimir Homutov <vl@nginx.com>
parents: 1935
diff changeset
797 ngx_str_set(v, "bar");
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
798
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
799 /* iterate over the list */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
800
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
801 part = &amp;list->part;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
802 v = part->elts;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
803
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
804 for (i = 0; /* void */; i++) {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
805
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
806 if (i >= part->nelts) {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
807 if (part->next == NULL) {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
808 break;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
809 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
810
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
811 part = part->next;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
812 v = part->elts;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
813 i = 0;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
814 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
815
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
816 ngx_do_smth(&amp;v[i]);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
817 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
818 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
819
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
820 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
821 The primary use for the list in nginx is HTTP input and output headers.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
822 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
823
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
824 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
825 The list does not support item removal.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
826 However, when needed, items can internally be marked as missing without actual
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
827 removing from the list.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
828 For example, HTTP output headers which are stored as
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
829 <literal>ngx_table_elt_t</literal> objects, are marked as missing by setting
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
830 the <literal>hash</literal> field of <literal>ngx_table_elt_t</literal> to
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
831 zero. Such items are explicitly skipped, when iterating over the headers.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
832 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
833
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
834 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
835
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
836
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
837 <section name="Queue" id="queue">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
838
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
839 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
840 Queue in nginx is an intrusive doubly linked list, with each node defined as
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
841 follows:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
842 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
843
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
844
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
845 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
846 typedef struct ngx_queue_s ngx_queue_t;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
847
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
848 struct ngx_queue_s {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
849 ngx_queue_t *prev;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
850 ngx_queue_t *next;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
851 };
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
852 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
853
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
854 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
855 The head queue node is not linked with any data. Before using, the list head
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
856 should be initialized with <literal>ngx_queue_init(q)</literal> call.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
857 Queues support the following operations:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
858 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
859
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
860 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
861 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
862
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
863 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
864 <literal>ngx_queue_insert_head(h, x)</literal>,
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
865 <literal>ngx_queue_insert_tail(h, x)</literal> — insert a new node
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
866 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
867
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
868 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
869 <literal>ngx_queue_remove(x)</literal> — remove a queue node
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
870 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
871
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
872 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
873 <literal>ngx_queue_split(h, q, n)</literal> — split a queue at a node,
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
874 queue tail is returned in a separate queue
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
875 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
876
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
877 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
878 <literal>ngx_queue_add(h, n)</literal> — add second queue to the first queue
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
879 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
880
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
881 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
882 <literal>ngx_queue_head(h)</literal>,
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
883 <literal>ngx_queue_last(h)</literal> — get first or last queue node
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
884 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
885
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
886 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
887 <literal>ngx_queue_sentinel(h)</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
888 - get a queue sentinel object to end iteration at
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
889 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
890
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
891 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
892 <literal>ngx_queue_data(q, type, link)</literal> — get reference to the beginning of a
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
893 queue node data structure, considering the queue field offset in it
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
894 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
895
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
896 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
897 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
898
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
899 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
900 Example:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
901 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
902
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
903
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
904 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
905 typedef struct {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
906 ngx_str_t value;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
907 ngx_queue_t queue;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
908 } ngx_foo_t;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
909
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
910 ngx_foo_t *f;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
911 ngx_queue_t values;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
912
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
913 ngx_queue_init(&amp;values);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
914
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
915 f = ngx_palloc(pool, sizeof(ngx_foo_t));
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
916 if (f == NULL) { /* error */ }
1936
8f996938fe23 Style: proper quotes usage.
Vladimir Homutov <vl@nginx.com>
parents: 1935
diff changeset
917 ngx_str_set(&amp;f->value, "foo");
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
918
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
919 ngx_queue_insert_tail(&amp;values, f);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
920
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
921 /* insert more nodes here */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
922
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
923 for (q = ngx_queue_head(&amp;values);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
924 q != ngx_queue_sentinel(&amp;values);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
925 q = ngx_queue_next(q))
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
926 {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
927 f = ngx_queue_data(q, ngx_foo_t, queue);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
928
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
929 ngx_do_smth(&amp;f->value);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
930 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
931 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
932
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
933 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
934
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
935
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
936 <section name="Red-Black tree" id="red_black_tree">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
937
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
938 <para>
1915
8b7c3b0ef1a4 Semantically marked paths.
Vladimir Homutov <vl@nginx.com>
parents: 1914
diff changeset
939 The <path>src/core/ngx_rbtree.h</path> header file provides access to the
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
940 effective implementation of red-black trees.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
941 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
942
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
943
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
944 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
945 typedef struct {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
946 ngx_rbtree_t rbtree;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
947 ngx_rbtree_node_t sentinel;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
948
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
949 /* custom per-tree data here */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
950 } my_tree_t;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
951
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
952 typedef struct {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
953 ngx_rbtree_node_t rbnode;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
954
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
955 /* custom per-node data */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
956 foo_t val;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
957 } my_node_t;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
958 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
959
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
960 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
961 To deal with a tree as a whole, you need two nodes: root and sentinel.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
962 Typically, they are added to some custom structure, thus allowing to
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
963 organize your data into a tree which leaves contain a link to or embed
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
964 your data.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
965 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
966
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
967 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
968 To initialize a tree:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
969 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
970
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
971
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
972 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
973 my_tree_t root;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
974
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
975 ngx_rbtree_init(&amp;root.rbtree, &amp;root.sentinel, insert_value_function);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
976 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
977
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
978 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
979 The <literal>insert_value_function</literal> is a function that is
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
980 responsible for traversing the tree and inserting new values into correct
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
981 place.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
982 For example, the <literal>ngx_str_rbtree_insert_value</literal> functions is
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
983 designed to deal with <literal>ngx_str_t</literal> type.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
984 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
985
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
986
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
987 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
988 void ngx_str_rbtree_insert_value(ngx_rbtree_node_t *temp,
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
989 ngx_rbtree_node_t *node,
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
990 ngx_rbtree_node_t *sentinel)
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
991 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
992
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
993 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
994 Its arguments are pointers to a root node of an insertion, newly created node
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
995 to be added, and a tree sentinel.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
996 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
997
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
998 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
999 The traversal is pretty straightforward and can be demonstrated with the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1000 following lookup function pattern:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1001 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1002
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1003
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1004 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1005 my_node_t *
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1006 my_rbtree_lookup(ngx_rbtree_t *rbtree, foo_t *val, uint32_t hash)
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1007 {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1008 ngx_int_t rc;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1009 my_node_t *n;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1010 ngx_rbtree_node_t *node, *sentinel;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1011
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1012 node = rbtree->root;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1013 sentinel = rbtree->sentinel;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1014
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1015 while (node != sentinel) {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1016
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1017 n = (my_node_t *) node;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1018
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1019 if (hash != node->key) {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1020 node = (hash &lt; node->key) ? node->left : node->right;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1021 continue;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1022 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1023
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1024 rc = compare(val, node->val);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1025
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1026 if (rc &lt; 0) {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1027 node = node->left;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1028 continue;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1029 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1030
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1031 if (rc > 0) {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1032 node = node->right;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1033 continue;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1034 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1035
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1036 return n;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1037 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1038
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1039 return NULL;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1040 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1041 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1042
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1043 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1044 The <literal>compare()</literal> is a classic comparator function returning
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1045 value less, equal or greater than zero. To speed up lookups and avoid comparing
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1046 user objects that can be big, integer hash field is used.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1047 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1048
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1049 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1050 To add a node to a tree, allocate a new node, initialize it and call
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1051 <literal>ngx_rbtree_insert()</literal>:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1052 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1053
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1054
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1055 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1056 my_node_t *my_node;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1057 ngx_rbtree_node_t *node;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1058
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1059 my_node = ngx_palloc(...);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1060 init_custom_data(&amp;my_node->val);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1061
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1062 node = &amp;my_node->rbnode;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1063 node->key = create_key(my_node->val);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1064
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1065 ngx_rbtree_insert(&amp;root->rbtree, node);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1066 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1067
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1068 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1069 to remove a node:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1070 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1071
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1072
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1073 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1074 ngx_rbtree_delete(&amp;root->rbtree, node);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1075 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1076
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1077 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1078
1914
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1079 <section name="Hash" id="hash">
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1080
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1081 <para>
1920
de5251816480 Fixed a typo.
Vladimir Homutov <vl@nginx.com>
parents: 1919
diff changeset
1082 Hash table functions are declared in <path>src/core/ngx_hash.h</path>.
1914
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1083 Exact and wildcard matching is supported.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1084 The latter requires extra setup and is described in a separate section below.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1085 </para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1086
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1087 <para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1088 To initialize a hash, one needs to know the number of elements in advance,
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1089 so that nginx can build the hash optimally.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1090 Two parameters that need to be configured are <literal>max_size</literal>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1091 and <literal>bucket_size</literal>.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1092 The details of setting up these are provided in a separate
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1093 <link doc="../hash.xml">document</link>.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1094 Usually, these two parameters are configurable by user.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1095 Hash initialization settings are stored as the
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1096 <literal>ngx_hash_init_t</literal> type,
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1097 and the hash itself is <literal>ngx_hash_t</literal>:
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1098 <programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1099 ngx_hash_t foo_hash;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1100 ngx_hash_init_t hash;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1101
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1102 hash.hash = &amp;foo_hash;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1103 hash.key = ngx_hash_key;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1104 hash.max_size = 512;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1105 hash.bucket_size = ngx_align(64, ngx_cacheline_size);
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1106 hash.name = "foo_hash";
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1107 hash.pool = cf-&gt;pool;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1108 hash.temp_pool = cf-&gt;temp_pool;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1109 </programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1110 The <literal>key</literal> is a pointer to a function that creates hash integer
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1111 key from a string.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1112 Two generic functions are provided:
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1113 <literal>ngx_hash_key(data, len)</literal> and
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1114 <literal>ngx_hash_key_lc(data, len)</literal>.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1115 The latter converts a string to lowercase and thus requires the passed string to
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1116 be writable.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1117 If this is not true, <literal>NGX_HASH_READONLY_KEY</literal> flag
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1118 may be passed to the function, initializing array keys (see below).
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1119 </para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1120
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1121 <para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1122 The hash keys are stored in <literal>ngx_hash_keys_arrays_t</literal> and
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1123 are initialized with <literal>ngx_hash_keys_array_init(arr, type)</literal>:
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1124 <programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1125 ngx_hash_keys_arrays_t foo_keys;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1126
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1127 foo_keys.pool = cf-&gt;pool;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1128 foo_keys.temp_pool = cf-&gt;temp_pool;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1129
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1130 ngx_hash_keys_array_init(&amp;foo_keys, NGX_HASH_SMALL);
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1131 </programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1132 The second parameter can be either <literal>NGX_HASH_SMALL</literal> or
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1133 <literal>NGX_HASH_LARGE</literal> and controls the amount of preallocated
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1134 resources for the hash.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1135 If you expect the hash to contain thousands elements,
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1136 use <literal>NGX_HASH_LARGE</literal>.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1137 </para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1138
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1139 <para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1140 The <literal>ngx_hash_add_key(keys_array, key, value, flags)</literal>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1141 function is used to insert keys into hash keys array;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1142 <programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1143 ngx_str_t k1 = ngx_string("key1");
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1144 ngx_str_t k2 = ngx_string("key2");
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1145
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1146 ngx_hash_add_key(&amp;foo_keys, &amp;k1, &amp;my_data_ptr_1, NGX_HASH_READONLY_KEY);
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1147 ngx_hash_add_key(&amp;foo_keys, &amp;k2, &amp;my_data_ptr_2, NGX_HASH_READONLY_KEY);
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1148 </programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1149 </para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1150
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1151 <para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1152 Now, the hash table may be built using the call to
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1153 <literal>ngx_hash_init(hinit, key_names, nelts)</literal>:
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1154
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1155 <programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1156 ngx_hash_init(&amp;hash, foo_keys.keys.elts, foo_keys.keys.nelts);
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1157 </programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1158
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1159 This may fail, if <literal>max_size</literal> or <literal>bucket_size</literal>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1160 parameters are not big enough.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1161 When the hash is built, <literal>ngx_hash_find(hash, key, name, len)</literal>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1162 function may be used to look up elements:
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1163 <programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1164 my_data_t *data;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1165 ngx_uint_t key;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1166
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1167 key = ngx_hash_key(k1.data, k1.len);
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1168
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1169 data = ngx_hash_find(&amp;foo_hash, key, k1.data, k1.len);
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1170 if (data == NULL) {
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1171 /* key not found */
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1172 }
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1173 </programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1174
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1175 </para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1176
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1177 <section name="Wildcard matching" id="wildcard_matching">
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1178
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1179 <para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1180 To create a hash that works with wildcards,
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1181 <literal>ngx_hash_combined_t</literal> type is used.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1182 It includes the hash type described above and has two additional keys arrays:
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1183 <literal>dns_wc_head</literal> and <literal>dns_wc_tail</literal>.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1184 The initialization of basic properties is done similarly to a usual hash:
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1185 <programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1186 ngx_hash_init_t hash
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1187 ngx_hash_combined_t foo_hash;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1188
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1189 hash.hash = &amp;foo_hash.hash;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1190 hash.key = ...;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1191 </programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1192 </para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1193
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1194 <para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1195 It is possible to add wildcard keys using the
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1196 <literal>NGX_HASH_WILDCARD_KEY</literal> flag:
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1197 <programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1198 /* k1 = ".example.org"; */
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1199 /* k2 = "foo.*"; */
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1200 ngx_hash_add_key(&amp;foo_keys, &amp;k1, &amp;data1, NGX_HASH_WILDCARD_KEY);
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1201 ngx_hash_add_key(&amp;foo_keys, &amp;k2, &amp;data2, NGX_HASH_WILDCARD_KEY);
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1202 </programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1203 The function recognizes wildcards and adds keys into corresponding arrays.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1204 Please refer to the
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1205 <link doc="../http/ngx_http_map_module.xml" id="map"/> module
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1206 documentation for the description of the wildcard syntax and
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1207 matching algorithm.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1208 </para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1209
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1210 <para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1211 Depending on the contents of added keys, you may need to initialize up to three
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1212 keys arrays: one for exact matching (described above), and two for matching
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1213 starting from head or tail of a string:
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1214 <programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1215 if (foo_keys.dns_wc_head.nelts) {
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1216
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1217 ngx_qsort(foo_keys.dns_wc_head.elts,
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1218 (size_t) foo_keys.dns_wc_head.nelts,
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1219 sizeof(ngx_hash_key_t),
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1220 cmp_dns_wildcards);
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1221
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1222 hash.hash = NULL;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1223 hash.temp_pool = pool;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1224
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1225 if (ngx_hash_wildcard_init(&amp;hash, foo_keys.dns_wc_head.elts,
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1226 foo_keys.dns_wc_head.nelts)
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1227 != NGX_OK)
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1228 {
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1229 return NGX_ERROR;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1230 }
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1231
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1232 foo_hash.wc_head = (ngx_hash_wildcard_t *) hash.hash;
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1233 }
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1234 </programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1235 The keys array needs to be sorted, and initialization results must be added
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1236 to the combined hash.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1237 The initialization of <literal>dns_wc_tail</literal> array is done similarly.
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1238 </para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1239
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1240 <para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1241 The lookup in a combined hash is handled by the
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1242 <literal>ngx_hash_find_combined(chash, key, name, len)</literal>:
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1243 <programlisting>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1244 /* key = "bar.example.org"; — will match ".example.org" */
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1245 /* key = "foo.example.com"; — will match "foo.*" */
1914
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1246
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1247 hkey = ngx_hash_key(key.data, key.len);
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1248 res = ngx_hash_find_combined(&amp;foo_hash, hkey, key.data, key.len);
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1249 </programlisting>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1250 </para>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1251
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1252 </section>
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1253
f8659301a260 Added hash API description.
Vladimir Homutov <vl@nginx.com>
parents: 1907
diff changeset
1254 </section>
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1255
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1256 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1257
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1258
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1259 <section name="Memory management" id="memory_management">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1260
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1261
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1262 <section name="Heap" id="heap">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1263
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1264 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1265 To allocate memory from system heap, the following functions are provided by
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1266 nginx:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1267 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1268
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1269 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1270 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1271
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1272 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1273 <literal>ngx_alloc(size, log)</literal> — allocate memory from system heap.
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1274 This is a wrapper around <literal>malloc()</literal> with logging support.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1275 Allocation error and debugging information is logged to <literal>log</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1276 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1277
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1278 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1279 <literal>ngx_calloc(size, log)</literal> — same as
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1280 <literal>ngx_alloc()</literal>, but memory is filled with zeroes after
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1281 allocation
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1282 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1283
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1284 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1285 <literal>ngx_memalign(alignment, size, log)</literal> — allocate aligned memory
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1286 from system heap. This is a wrapper around <literal>posix_memalign()</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1287 on those platforms which provide it.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1288 Otherwise implementation falls back to <literal>ngx_alloc()</literal> which
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1289 provides maximum alignment
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1290 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1291
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1292 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1293 <literal>ngx_free(p)</literal> — free allocated memory.
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1294 This is a wrapper around <literal>free()</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1295 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1296
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1297 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1298 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1299
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1300 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1301
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1302
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1303 <section name="Pool" id="pool">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1304
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1305 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1306 Most nginx allocations are done in pools. Memory allocated in an nginx pool is
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1307 freed automatically when the pool in destroyed. This provides good
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1308 allocation performance and makes memory control easy.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1309 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1310
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1311 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1312 A pool internally allocates objects in continuous blocks of memory. Once a
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1313 block is full, a new one is allocated and added to the pool memory
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1314 block list. When a large allocation is requested which does not fit into
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1315 a block, such allocation is forwarded to the system allocator and the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1316 returned pointer is stored in the pool for further deallocation.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1317 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1318
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1319 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1320 Nginx pool has the type <literal>ngx_pool_t</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1321 The following operations are supported:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1322 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1323
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1324 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1325 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1326
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1327 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1328 <literal>ngx_create_pool(size, log)</literal> — create a pool with given
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1329 block size. The pool object returned is allocated in the pool as well.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1330 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1331
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1332 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1333 <literal>ngx_destroy_pool(pool)</literal> — free all pool memory, including
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1334 the pool object itself.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1335 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1336
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1337 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1338 <literal>ngx_palloc(pool, size)</literal> — allocate aligned memory from pool
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1339 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1340
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1341 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1342 <literal>ngx_pcalloc(pool, size)</literal> — allocated aligned memory
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1343 from pool and fill it with zeroes
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1344 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1345
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1346 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1347 <literal>ngx_pnalloc(pool, size)</literal> — allocate unaligned memory from pool.
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1348 Mostly used for allocating strings
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1349 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1350
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1351 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1352 <literal>ngx_pfree(pool, p)</literal> — free memory, previously allocated
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1353 in the pool.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1354 Only allocations, forwarded to the system allocator, can be freed.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1355 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1356
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1357 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1358 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1359
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1360 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1361 u_char *p;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1362 ngx_str_t *s;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1363 ngx_pool_t *pool;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1364
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1365 pool = ngx_create_pool(1024, log);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1366 if (pool == NULL) { /* error */ }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1367
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1368 s = ngx_palloc(pool, sizeof(ngx_str_t));
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1369 if (s == NULL) { /* error */ }
1936
8f996938fe23 Style: proper quotes usage.
Vladimir Homutov <vl@nginx.com>
parents: 1935
diff changeset
1370 ngx_str_set(s, "foo");
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1371
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1372 p = ngx_pnalloc(pool, 3);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1373 if (p == NULL) { /* error */ }
1936
8f996938fe23 Style: proper quotes usage.
Vladimir Homutov <vl@nginx.com>
parents: 1935
diff changeset
1374 ngx_memcpy(p, "foo", 3);
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1375 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1376
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1377 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1378 Since chain links <literal>ngx_chain_t</literal> are actively used in nginx,
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1379 nginx pool provides a way to reuse them.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1380 The <literal>chain</literal> field of <literal>ngx_pool_t</literal> keeps a
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1381 list of previously allocated links ready for reuse. For efficient allocation of
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1382 a chain link in a pool, the function
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1383 <literal>ngx_alloc_chain_link(pool)</literal> should be used.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1384 This function looks up a free chain link in the pool list and only if it's
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1385 empty allocates a new one. To free a link <literal>ngx_free_chain(pool, cl)</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1386 should be called.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1387 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1388
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1389 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1390 Cleanup handlers can be registered in a pool.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1391 Cleanup handler is a callback with an argument which is called when pool is
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1392 destroyed.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1393 Pool is usually tied with a specific nginx object (like HTTP request) and
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1394 destroyed in the end of that object’s lifetime, releasing the object itself.
1902
862e96a39fe3 Typo fixed.
Maxim Konovalov <maxim@nginx.com>
parents: 1899
diff changeset
1395 Registering a pool cleanup is a convenient way to release resources, close file
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1396 descriptors or make final adjustments to shared data, associated with the main
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1397 object.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1398 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1399
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1400 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1401 A pool cleanup is registered by calling <literal>ngx_pool_cleanup_add(pool,
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1402 size)</literal> which returns <literal>ngx_pool_cleanup_t</literal> pointer to
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1403 be filled by the caller. The <literal>size</literal> argument allows allocating
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1404 context for the cleanup handler.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1405 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1406
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1407
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1408 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1409 ngx_pool_cleanup_t *cln;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1410
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1411 cln = ngx_pool_cleanup_add(pool, 0);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1412 if (cln == NULL) { /* error */ }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1413
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1414 cln->handler = ngx_my_cleanup;
1936
8f996938fe23 Style: proper quotes usage.
Vladimir Homutov <vl@nginx.com>
parents: 1935
diff changeset
1415 cln->data = "foo";
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1416
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1417 ...
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1418
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1419 static void
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1420 ngx_my_cleanup(void *data)
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1421 {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1422 u_char *msg = data;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1423
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1424 ngx_do_smth(msg);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1425 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1426 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1427
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1428 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1429
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1430
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1431 <section name="Shared memory" id="shared_memory">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1432
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1433 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1434 Shared memory is used by nginx to share common data between processes.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1435 Function <literal>ngx_shared_memory_add(cf, name, size, tag)</literal> adds a
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1436 new shared memory entry <literal>ngx_shm_zone_t</literal> to the cycle. The
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1437 function receives <literal>name</literal> and <literal>size</literal> of the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1438 zone.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1439 Each shared zone must have a unique name.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1440 If a shared zone entry with the provided name exists, the old zone entry is
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1441 reused, if its tag value matches too.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1442 Mismatched tag is considered an error.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1443 Usually, the address of the module structure is passed as tag, making it
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1444 possible to reuse shared zones by name within one nginx module.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1445 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1446
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1447 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1448 The shared memory entry structure <literal>ngx_shm_zone_t</literal> has the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1449 following fields:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1450 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1451
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1452 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1453 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1454
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1455 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1456 <literal>init</literal> — initialization callback, called after shared zone is
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1457 mapped to actual memory
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1458 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1459
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1460 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1461 <literal>data</literal> — data context, used to pass arbitrary data to the
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1462 <literal>init</literal> callback
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1463 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1464
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1465 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1466 <literal>noreuse</literal> — flag, disabling shared zone reuse from the
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1467 old cycle
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1468 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1469
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1470 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1471 <literal>tag</literal> — shared zone tag
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1472 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1473
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1474 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1475 <literal>shm</literal> — platform-specific object of type
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1476 <literal>ngx_shm_t</literal>, having at least the following fields:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1477 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1478
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1479 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1480 <literal>addr</literal> — mapped shared memory address, initially NULL
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1481 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1482
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1483 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1484 <literal>size</literal> — shared memory size
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1485 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1486
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1487 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1488 <literal>name</literal> — shared memory name
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1489 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1490
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1491 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1492 <literal>log</literal> — shared memory log
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1493 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1494
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1495 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1496 <literal>exists</literal> — flag, showing that shared memory was inherited
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1497 from the master process (Windows-specific)
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1498 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1499
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1500 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1501 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1502
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1503 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1504 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1505
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1506 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1507 Shared zone entries are mapped to actual memory in
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1508 <literal>ngx_init_cycle()</literal> after configuration is parsed.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1509 On POSIX systems, <literal>mmap()</literal> syscall is used to create shared
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1510 anonymous mapping.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1511 On Windows, <literal>CreateFileMapping()/MapViewOfFileEx()</literal> pair is
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1512 used.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1513 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1514
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1515 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1516 For allocating in shared memory, nginx provides slab pool
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1517 <literal>ngx_slab_pool_t</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1518 In each nginx shared zone, a slab pool is automatically created for allocating
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1519 memory in that zone.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1520 The pool is located in the beginning of the shared zone and can be accessed by
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1521 the expression <literal>(ngx_slab_pool_t *) shm_zone->shm.addr</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1522 Allocation in shared zone is done by calling one of the functions
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1523 <literal>ngx_slab_alloc(pool, size)/ngx_slab_calloc(pool, size)</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1524 Memory is freed by calling <literal>ngx_slab_free(pool, p)</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1525 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1526
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1527 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1528 Slab pool divides all shared zone into pages.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1529 Each page is used for allocating objects of the same size.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1530 Only the sizes which are powers of 2, and not less than 8, are considered.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1531 Other sizes are rounded up to one of these values.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1532 For each page, a bitmask is kept, showing which blocks within that page are in
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1533 use and which are free for allocation.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1534 For sizes greater than half-page (usually, 2048 bytes), allocation is done by
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1535 entire pages.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1536 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1537
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1538 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1539 To protect data in shared memory from concurrent access, mutex is available in
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1540 the <literal>mutex</literal> field of <literal>ngx_slab_pool_t</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1541 The mutex is used by the slab pool while allocating and freeing memory.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1542 However, it can be used to protect any other user data structures,
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1543 allocated in the shared zone.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1544 Locking is done by calling
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1545 <literal>ngx_shmtx_lock(&amp;shpool->mutex)</literal>, unlocking is done by
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1546 calling <literal>ngx_shmtx_unlock(&amp;shpool->mutex)</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1547 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1548
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1549
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1550 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1551 ngx_str_t name;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1552 ngx_foo_ctx_t *ctx;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1553 ngx_shm_zone_t *shm_zone;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1554
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1555 ngx_str_set(&amp;name, "foo");
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1556
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1557 /* allocate shared zone context */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1558 ctx = ngx_pcalloc(cf->pool, sizeof(ngx_foo_ctx_t));
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1559 if (ctx == NULL) {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1560 /* error */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1561 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1562
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1563 /* add an entry for 65k shared zone */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1564 shm_zone = ngx_shared_memory_add(cf, &amp;name, 65536, &amp;ngx_foo_module);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1565 if (shm_zone == NULL) {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1566 /* error */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1567 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1568
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1569 /* register init callback and context */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1570 shm_zone->init = ngx_foo_init_zone;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1571 shm_zone->data = ctx;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1572
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1573
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1574 ...
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1575
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1576
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1577 static ngx_int_t
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1578 ngx_foo_init_zone(ngx_shm_zone_t *shm_zone, void *data)
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1579 {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1580 ngx_foo_ctx_t *octx = data;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1581
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1582 size_t len;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1583 ngx_foo_ctx_t *ctx;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1584 ngx_slab_pool_t *shpool;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1585
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1586 value = shm_zone->data;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1587
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1588 if (octx) {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1589 /* reusing a shared zone from old cycle */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1590 ctx->value = octx->value;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1591 return NGX_OK;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1592 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1593
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1594 shpool = (ngx_slab_pool_t *) shm_zone->shm.addr;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1595
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1596 if (shm_zone->shm.exists) {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1597 /* initialize shared zone context in Windows nginx worker */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1598 ctx->value = shpool->data;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1599 return NGX_OK;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1600 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1601
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1602 /* initialize shared zone */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1603
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1604 ctx->value = ngx_slab_alloc(shpool, sizeof(ngx_uint_t));
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1605 if (ctx->value == NULL) {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1606 return NGX_ERROR;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1607 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1608
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1609 shpool->data = ctx->value;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1610
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1611 return NGX_OK;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1612 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1613 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1614
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1615 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1616
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1617
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1618 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1619
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1620
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1621 <section name="Logging" id="logging">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1622
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1623 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1624 For logging nginx code uses <literal>ngx_log_t</literal> objects.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1625 Nginx logger provides support for several types of output:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1626
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1627 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1628
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1629 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1630 stderr — logging to standard error output
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1631 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1632
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1633 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1634 file — logging to file
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1635 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1636
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1637 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1638 syslog — logging to syslog
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1639 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1640
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1641 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1642 memory — logging to internal memory storage for development purposes.
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1643 The memory could be accessed later with debugger
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1644 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1645
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1646 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1647 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1648
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1649 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1650 A logger instance may actually be a chain of loggers, linked to each other with
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1651 the <literal>next</literal> field.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1652 Each message is written to all loggers in chain.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1653 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1654
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1655 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1656 Each logger has an error level which limits the messages written to that log.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1657 The following error levels are supported by nginx:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1658 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1659
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1660 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1661 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1662
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1663 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1664 <literal>NGX_LOG_EMERG</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1665 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1666
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1667 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1668 <literal>NGX_LOG_ALERT</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1669 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1670
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1671 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1672 <literal>NGX_LOG_CRIT</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1673 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1674
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1675 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1676 <literal>NGX_LOG_ERR</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1677 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1678
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1679 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1680 <literal>NGX_LOG_WARN</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1681 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1682
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1683 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1684 <literal>NGX_LOG_NOTICE</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1685 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1686
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1687 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1688 <literal>NGX_LOG_INFO</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1689 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1690
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1691 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1692 <literal>NGX_LOG_DEBUG</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1693 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1694
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1695 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1696 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1697
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1698 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1699 For debug logging, debug mask is checked as well. The following debug masks
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1700 exist:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1701 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1702
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1703 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1704 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1705
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1706 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1707 <literal>NGX_LOG_DEBUG_CORE</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1708 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1709
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1710 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1711 <literal>NGX_LOG_DEBUG_ALLOC</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1712 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1713
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1714 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1715 <literal>NGX_LOG_DEBUG_MUTEX</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1716 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1717
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1718 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1719 <literal>NGX_LOG_DEBUG_EVENT</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1720 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1721
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1722 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1723 <literal>NGX_LOG_DEBUG_HTTP</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1724 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1725
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1726 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1727 <literal>NGX_LOG_DEBUG_MAIL</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1728 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1729
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1730 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1731 <literal>NGX_LOG_DEBUG_STREAM</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1732 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1733
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1734 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1735 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1736
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1737 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1738 Normally, loggers are created by existing nginx code from
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1739 <literal>error_log</literal> directives and are available at nearly every stage
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1740 of processing in cycle, configuration, client connection and other objects.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1741 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1742
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1743 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1744 Nginx provides the following logging macros:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1745 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1746
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1747 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1748 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1749
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1750 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1751 <literal>ngx_log_error(level, log, err, fmt, ...)</literal> — error logging
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1752 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1753
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1754 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1755 <literal>ngx_log_debug0(level, log, err, fmt)</literal>,
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1756 <literal>ngx_log_debug1(level, log, err, fmt, arg1)</literal> etc — debug
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1757 logging, up to 8 formatting arguments are supported
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1758 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1759
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1760 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1761 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1762
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1763 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1764 A log message is formatted in a buffer of size
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1765 <literal>NGX_MAX_ERROR_STR</literal> (currently, 2048 bytes) on stack.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1766 The message is prepended with error level, process PID, connection id (stored
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1767 in <literal>log->connection</literal>) and system error text.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1768 For non-debug messages <literal>log->handler</literal> is called as well to
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1769 prepend more specific information to the log message.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1770 HTTP module sets <literal>ngx_http_log_error()</literal> function as log
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1771 handler to log client and server addresses, current action (stored in
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1772 <literal>log->action</literal>), client request line, server name etc.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1773 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1774
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1775 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1776 Example:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1777 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1778
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1779
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1780 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1781 /* specify what is currently done */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1782 log->action = "sending mp4 to client”;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1783
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1784 /* error and debug log */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1785 ngx_log_error(NGX_LOG_INFO, c->log, 0, "client prematurely
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1786 closed connection”);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1787
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1788 ngx_log_debug2(NGX_LOG_DEBUG_HTTP, mp4->file.log, 0,
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1789 "mp4 start:%ui, length:%ui”, mp4->start, mp4->length);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1790 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1791
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1792 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1793 Logging result:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1794 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1795
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1796
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1797 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1798 2016/09/16 22:08:52 [info] 17445#0: *1 client prematurely closed connection while
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1799 sending mp4 to client, client: 127.0.0.1, server: , request: "GET /file.mp4 HTTP/1.1”
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1800 2016/09/16 23:28:33 [debug] 22140#0: *1 mp4 start:0, length:10000
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1801 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1802
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1803 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1804
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1805
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1806 <section name="Cycle" id="cycle">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1807
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1808 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1809 Cycle object keeps nginx runtime context, created from a specific
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1810 configuration.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1811 The type of the cycle is <literal>ngx_cycle_t</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1812 Upon configuration reload a new cycle is created from the new version of nginx
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1813 configuration.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1814 The old cycle is usually deleted after a new one is successfully created.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1815 Currently active cycle is held in the <literal>ngx_cycle</literal> global
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1816 variable and is inherited by newly started nginx workers.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1817 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1818
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1819 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1820 A cycle is created by the function <literal>ngx_init_cycle()</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1821 The function receives the old cycle as the argument.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1822 It's used to locate the configuration file and inherit as much resources as
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1823 possible from the old cycle to keep nginx running smoothly.
1936
8f996938fe23 Style: proper quotes usage.
Vladimir Homutov <vl@nginx.com>
parents: 1935
diff changeset
1824 When nginx starts, a fake cycle called “init cycle” is created and is then
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1825 replaced by a normal cycle, built from configuration.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1826 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1827
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1828 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1829 Some members of the cycle:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1830 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1831
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1832 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1833 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1834
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1835 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1836 <literal>pool</literal> — cycle pool. Created for each new cycle
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1837 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1838
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1839 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1840 <literal>log</literal> — cycle log. Initially, this log is inherited from the
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1841 old cycle.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1842 After reading configuration, this member is set to point to
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1843 <literal>new_log</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1844 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1845
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1846 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1847 <literal>new_log</literal> — cycle log, created by the configuration.
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1848 It's affected by the root scope <literal>error_log</literal> directive
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1849 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1850
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1851 <listitem>
1981
082724c57c38 Fixes in cycle section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1980
diff changeset
1852 <literal>connections</literal>, <literal>connection_n</literal> —
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1853 array of connections of type <literal>ngx_connection_t</literal>, created by
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1854 the event module while initializing each nginx worker.
1981
082724c57c38 Fixes in cycle section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1980
diff changeset
1855 The number of connections <literal>connection_n</literal> is set by the
082724c57c38 Fixes in cycle section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1980
diff changeset
1856 <literal>worker_connections</literal> directive
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1857 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1858
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1859 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1860 <literal>free_connections</literal>,
1981
082724c57c38 Fixes in cycle section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1980
diff changeset
1861 <literal>free_connection_n</literal> — list and number of currently available
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1862 connections.
1981
082724c57c38 Fixes in cycle section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1980
diff changeset
1863 If no connections are available, nginx worker refuses to accept new clients or
082724c57c38 Fixes in cycle section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1980
diff changeset
1864 connect to upstream servers
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1865 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1866
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1867 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1868 <literal>files</literal>, <literal>files_n</literal> — array for mapping file
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1869 descriptors to nginx connections.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1870 This mapping is used by the event modules, having the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1871 <literal>NGX_USE_FD_EVENT</literal> flag (currently, it's poll and devpoll)
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1872 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1873
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1874 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1875 <literal>conf_ctx</literal> — array of core module configurations.
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1876 The configurations are created and filled while reading nginx configuration
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1877 files
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1878 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1879
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1880 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1881 <literal>modules</literal>, <literal>modules_n</literal> — array of modules
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1882 <literal>ngx_module_t</literal>, both static and dynamic, loaded by current
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1883 configuration
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1884 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1885
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1886 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1887 <literal>listening</literal> — array of listening objects
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1888 <literal>ngx_listening_t</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1889 Listening objects are normally added by the the <literal>listen</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1890 directive of different modules which call the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1891 <literal>ngx_create_listening()</literal> function.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1892 Based on listening objects, listen sockets are created by nginx
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1893 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1894
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1895 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1896 <literal>paths</literal> — array of paths <literal>ngx_path_t</literal>.
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1897 Paths are added by calling the function <literal>ngx_add_path()</literal> from
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1898 modules which are going to operate on certain directories.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1899 These directories are created by nginx after reading configuration, if missing.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1900 Moreover, two handlers can be added for each path:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1901
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1902 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1903
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1904 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1905 path loader — executed only once in 60 seconds after starting or reloading
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1906 nginx. Normally, reads the directory and stores data in nginx shared
1936
8f996938fe23 Style: proper quotes usage.
Vladimir Homutov <vl@nginx.com>
parents: 1935
diff changeset
1907 memory. The handler is called from a dedicated nginx process “nginx
8f996938fe23 Style: proper quotes usage.
Vladimir Homutov <vl@nginx.com>
parents: 1935
diff changeset
1908 cache loader”
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1909 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1910
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1911 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1912 path manager — executed periodically. Normally, removes old files from the
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1913 directory and reflects these changes in nginx memory. The handler is
1936
8f996938fe23 Style: proper quotes usage.
Vladimir Homutov <vl@nginx.com>
parents: 1935
diff changeset
1914 called from a dedicated nginx process “nginx cache manager”
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1915 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1916
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1917 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1918 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1919
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1920 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1921 <literal>open_files</literal> — list of <literal>ngx_open_file_t</literal>
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1922 objects.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1923 An open file object is created by calling the function
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1924 <literal>ngx_conf_open_file()</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1925 After reading configuration nginx opens all files from the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1926 <literal>open_files</literal> list and stores file descriptors in the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1927 <literal>fd</literal> field of each open file object.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1928 The files are opened in append mode and created if missing.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1929 The files from this list are reopened by nginx workers upon receiving the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1930 reopen signal (usually it's <literal>USR1</literal>).
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1931 In this case the <literal>fd</literal> fields are changed to new descriptors.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1932 The open files are currently used for logging
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1933 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1934
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1935 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1936 <literal>shared_memory</literal> — list of shared memory zones, each added by
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1937 calling the <literal>ngx_shared_memory_add()</literal> function.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1938 Shared zones are mapped to the same address range in all nginx processes and
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1939 are used to share common data, for example HTTP cache in-memory tree
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1940 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1941
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1942 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1943 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1944
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1945 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1946
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1947 <section name="Buffer" id="buffer">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1948
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1949 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1950 For input/output operations, nginx provides the buffer type
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1951 <literal>ngx_buf_t</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1952 Normally, it's used to hold data to be written to a destination or read from a
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1953 source.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1954 Buffer can reference data in memory and in file.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1955 Technically it's possible that a buffer references both at the same time.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1956 Memory for the buffer is allocated separately and is not related to the buffer
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1957 structure <literal>ngx_buf_t</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1958 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1959
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1960 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1961 The structure <literal>ngx_buf_t</literal> has the following fields:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1962 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1963
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1964 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1965 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1966
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1967 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1968 <literal>start</literal>, <literal>end</literal> — the boundaries of memory
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1969 block, allocated for the buffer
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1970 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1971
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1972 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1973 <literal>pos</literal>, <literal>last</literal> — memory buffer boundaries,
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1974 normally a subrange of <literal>start</literal> .. <literal>end</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1975 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1976
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1977 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1978 <literal>file_pos</literal>, <literal>file_last</literal> — file buffer
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1979 boundaries, these are offsets from the beginning of the file
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1980 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1981
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1982 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1983 <literal>tag</literal> — unique value, used to distinguish buffers, created by
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1984 different nginx module, usually, for the purpose of buffer reuse
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1985 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1986
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1987 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1988 <literal>file</literal> — file object
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1989 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1990
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1991 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1992 <literal>temporary</literal> — flag, meaning that the buffer references
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1993 writable memory
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1994 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1995
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1996 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
1997 <literal>memory</literal> — flag, meaning that the buffer references read-only
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1998 memory
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
1999 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2000
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2001 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2002 <literal>in_file</literal> — flag, meaning that current buffer references data
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2003 in a file
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2004 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2005
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2006 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2007 <literal>flush</literal> — flag, meaning that all data prior to this buffer
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2008 should be flushed
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2009 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2010
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2011 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2012 <literal>recycled</literal> — flag, meaning that the buffer can be reused and
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2013 should be consumed as soon as possible
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2014 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2015
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2016 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2017 <literal>sync</literal> — flag, meaning that the buffer carries no data or
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2018 special signal like <literal>flush</literal> or <literal>last_buf</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2019 Normally, such buffers are considered an error by nginx. This flags allows
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2020 skipping the error checks
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2021 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2022
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2023 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2024 <literal>last_buf</literal> — flag, meaning that current buffer is the last in
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2025 output
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2026 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2027
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2028 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2029 <literal>last_in_chain</literal> — flag, meaning that there's no more data
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2030 buffers in a (sub)request
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2031 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2032
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2033 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2034 <literal>shadow</literal> — reference to another buffer, related to the current
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2035 buffer. Usually current buffer uses data from the shadow buffer. Once current
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2036 buffer is consumed, the shadow buffer should normally also be marked as
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2037 consumed
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2038 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2039
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2040 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2041 <literal>last_shadow</literal> — flag, meaning that current buffer is the last
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2042 buffer, referencing a particular shadow buffer
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2043 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2044
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2045 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2046 <literal>temp_file</literal> — flag, meaning that the buffer is in a temporary
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2047 file
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2048 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2049
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2050 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2051 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2052
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2053 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2054 For input and output buffers are linked in chains.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2055 Chain is a sequence of chain links <literal>ngx_chain_t</literal>, defined as
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2056 follows:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2057 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2058
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2059
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2060 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2061 typedef struct ngx_chain_s ngx_chain_t;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2062
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2063 struct ngx_chain_s {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2064 ngx_buf_t *buf;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2065 ngx_chain_t *next;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2066 };
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2067 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2068
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2069 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2070 Each chain link keeps a reference to its buffer and a reference to the next
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2071 chain link.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2072 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2073
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2074 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2075 Example of using buffers and chains:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2076 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2077
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2078
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2079 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2080 ngx_chain_t *
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2081 ngx_get_my_chain(ngx_pool_t *pool)
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2082 {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2083 ngx_buf_t *b;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2084 ngx_chain_t *out, *cl, **ll;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2085
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2086 /* first buf */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2087 cl = ngx_alloc_chain_link(pool);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2088 if (cl == NULL) { /* error */ }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2089
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2090 b = ngx_calloc_buf(pool);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2091 if (b == NULL) { /* error */ }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2092
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2093 b->start = (u_char *) "foo";
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2094 b->pos = b->start;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2095 b->end = b->start + 3;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2096 b->last = b->end;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2097 b->memory = 1; /* read-only memory */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2098
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2099 cl->buf = b;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2100 out = cl;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2101 ll = &amp;cl->next;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2102
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2103 /* second buf */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2104 cl = ngx_alloc_chain_link(pool);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2105 if (cl == NULL) { /* error */ }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2106
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2107 b = ngx_create_temp_buf(pool, 3);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2108 if (b == NULL) { /* error */ }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2109
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2110 b->last = ngx_cpymem(b->last, "foo", 3);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2111
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2112 cl->buf = b;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2113 cl->next = NULL;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2114 *ll = cl;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2115
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2116 return out;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2117 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2118 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2119
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2120 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2121
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2122
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2123 <section name="Networking" id="networking">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2124
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2125
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2126 <!--
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2127 <section name="Network data types" id="network_data_types">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2128
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2129 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2130 TBD: ngx_addr_t, ngx_url_t, ngx_socket_t, ngx_sockaddr_t, parse url, parse
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2131 address...
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2132 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2133
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2134 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2135 -->
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2136
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2137 <section name="Connection" id="connection">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2138
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2139 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2140 Connection type <literal>ngx_connection_t</literal> is a wrapper around a
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2141 socket descriptor. Some of the structure fields are:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2142 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2143
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2144 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2145 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2146
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2147 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2148 <literal>fd</literal> — socket descriptor
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2149 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2150
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2151 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2152 <literal>data</literal> — arbitrary connection context.
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2153 Normally, a pointer to a higher level object, built on top of the connection,
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2154 like HTTP request or Stream session
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2155 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2156
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2157 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2158 <literal>read</literal>, <literal>write</literal> — read and write events for
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2159 the connection
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2160 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2161
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2162 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2163 <literal>recv</literal>, <literal>send</literal>,
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2164 <literal>recv_chain</literal>, <literal>send_chain</literal> — I/O operations
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2165 for the connection
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2166 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2167
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2168 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2169 <literal>pool</literal> — connection pool
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2170 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2171
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2172 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2173 <literal>log</literal> — connection log
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2174 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2175
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2176 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2177 <literal>sockaddr</literal>, <literal>socklen</literal>,
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2178 <literal>addr_text</literal> — remote socket address in binary and text forms
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2179 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2180
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2181 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2182 <literal>local_sockaddr</literal>, <literal>local_socklen</literal> — local
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2183 socket address in binary form.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2184 Initially, these fields are empty.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2185 Function <literal>ngx_connection_local_sockaddr()</literal> should be used to
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2186 get socket local address
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2187 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2188
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2189 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2190 <literal>proxy_protocol_addr</literal>, <literal>proxy_protocol_port</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2191 - PROXY protocol client address and port, if PROXY protocol is enabled for the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2192 connection
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2193 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2194
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2195 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2196 <literal>ssl</literal> — nginx connection SSL context
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2197 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2198
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2199 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2200 <literal>reusable</literal> — flag, meaning, that the connection is at the
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2201 state, when it can be reused
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2202 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2203
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2204 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2205 <literal>close</literal> — flag, meaning, that the connection is being reused
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2206 and should be closed
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2207 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2208
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2209 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2210 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2211
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2212 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2213 An nginx connection can transparently encapsulate SSL layer.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2214 In this case the connection <literal>ssl</literal> field holds a pointer to an
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2215 <literal>ngx_ssl_connection_t</literal> structure, keeping all SSL-related data
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2216 for the connection, including <literal>SSL_CTX</literal> and
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2217 <literal>SSL</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2218 The handlers <literal>recv</literal>, <literal>send</literal>,
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2219 <literal>recv_chain</literal>, <literal>send_chain</literal> are set as well to
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2220 SSL functions.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2221 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2222
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2223 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2224 The number of connections per nginx worker is limited by the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2225 <literal>worker_connections</literal> value.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2226 All connection structures are pre-created when a worker starts and stored in
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2227 the <literal>connections</literal> field of the cycle object.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2228 To reach out for a connection structure, <literal>ngx_get_connection(s,
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2229 log)</literal> function is used.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2230 The function receives a socket descriptor <literal>s</literal> which needs to
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2231 be wrapped in a connection structure.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2232 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2233
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2234 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2235 Since the number of connections per worker is limited, nginx provides a
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2236 way to grab connections which are currently in use.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2237 To enable or disable reuse of a connection, function
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2238 <literal>ngx_reusable_connection(c, reusable)</literal> is called.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2239 Calling <literal>ngx_reusable_connection(c, 1)</literal> sets the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2240 <literal>reuse</literal> flag of the connection structure and inserts the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2241 connection in the <literal>reusable_connections_queue</literal> of the cycle.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2242 Whenever <literal>ngx_get_connection()</literal> finds out there are no
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2243 available connections in the <literal>free_connections</literal> list of the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2244 cycle, it calls <literal>ngx_drain_connections()</literal> to release a
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2245 specific number of reusable connections.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2246 For each such connection, the <literal>close</literal> flag is set and its read
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2247 handler is called which is supposed to free the connection by calling
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2248 <literal>ngx_close_connection(c)</literal> and make it available for reuse.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2249 To exit the state when a connection can be reused
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2250 <literal>ngx_reusable_connection(c, 0)</literal> is called.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2251 An example of reusable connections in nginx is HTTP client connections which
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2252 are marked as reusable until some data is received from the client.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2253 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2254
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2255 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2256
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2257
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2258 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2259
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2260
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2261 <section name="Events" id="events">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2262
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2263
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2264 <section name="Event" id="event">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2265
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2266 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2267 Event object <literal>ngx_event_t</literal> in nginx provides a way to be
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2268 notified of a specific event happening.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2269 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2270
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2271 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2272 Some of the fields of the <literal>ngx_event_t</literal> are:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2273 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2274
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2275 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2276 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2277
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2278 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2279 <literal>data</literal> — arbitrary event context, used in event handler,
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2280 usually, a pointer to a connection, tied with the event
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2281 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2282
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2283 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2284 <literal>handler</literal> — callback function to be invoked when the event
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2285 happens
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2286 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2287
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2288 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2289 <literal>write</literal> — flag, meaning that this is the write event.
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2290 Used to distinguish between read and write events
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2291 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2292
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2293 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2294 <literal>active</literal> — flag, meaning that the event is registered for
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2295 receiving I/O notifications, normally from notification mechanisms like epoll,
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2296 kqueue, poll
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2297 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2298
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2299 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2300 <literal>ready</literal> — flag, meaning that the event has received an
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2301 I/O notification
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2302 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2303
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2304 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2305 <literal>delayed</literal> — flag, meaning that I/O is delayed due to rate
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2306 limiting
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2307 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2308
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2309 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2310 <literal>timer</literal> — Red-Black tree node for inserting the event into
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2311 the timer tree
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2312 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2313
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2314 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2315 <literal>timer_set</literal> — flag, meaning that the event timer is set,
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2316 but not yet expired
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2317 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2318
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2319 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2320 <literal>timedout</literal> — flag, meaning that the event timer has expired
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2321 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2322
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2323 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2324 <literal>eof</literal> — read event flag, meaning that the eof has happened
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2325 while reading data
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2326 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2327
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2328 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2329 <literal>pending_eof</literal> — flag, meaning that the eof is pending on the
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2330 socket, even though there may be some data available before it.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2331 The flag is delivered via <literal>EPOLLRDHUP</literal> epoll event or
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2332 <literal>EV_EOF</literal> kqueue flag
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2333 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2334
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2335 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2336 <literal>error</literal> — flag, meaning that an error has happened while
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2337 reading (for read event) or writing (for write event)
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2338 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2339
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2340 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2341 <literal>cancelable</literal> — timer event flag, meaning that the event
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2342 handler should be called while performing nginx worker graceful shutdown, event
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2343 though event timeout has not yet expired. The flag provides a way to finalize
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2344 certain activities, for example, flush log files
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2345 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2346
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2347 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2348 <literal>posted</literal> — flag, meaning that the event is posted to queue
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2349 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2350
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2351 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2352 <literal>queue</literal> — queue node for posting the event to a queue
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2353 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2354
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2355 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2356 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2357
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2358 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2359
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2360
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2361 <section name="I/O events" id="i_o_events">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2362
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2363 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2364 Each connection, received with the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2365 <literal>ngx_get_connection()</literal> call, has two events attached to it:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2366 <literal>c->read</literal> and <literal>c->write</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2367 These events are used to receive notifications about the socket being ready for
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2368 reading or writing.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2369 All such events operate in Edge-Triggered mode, meaning that they only trigger
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2370 notifications when the state of the socket changes.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2371 For example, doing a partial read on a socket will not make nginx deliver a
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2372 repeated read notification until more data arrive in the socket.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2373 Even when the underlying I/O notification mechanism is essentially
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2374 Level-Triggered (poll, select etc), nginx will turn the notifications into
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2375 Edge-Triggered.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2376 To make nginx event notifications consistent across all notifications systems
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2377 on different platforms, it's required, that the functions
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2378 <literal>ngx_handle_read_event(rev, flags)</literal> and
1907
42ed974b83a5 Fixed the duplicated reference in development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1902
diff changeset
2379 <literal>ngx_handle_write_event(wev, lowat)</literal> are called after handling
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2380 an I/O socket notification or calling any I/O functions on that socket.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2381 Normally, these functions are called once in the end of each read or write
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2382 event handler.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2383 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2384
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2385 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2386
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2387
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2388 <section name="Timer events" id="timer_events">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2389
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2390 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2391 An event can be set to notify a timeout expiration.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2392 The function <literal>ngx_add_timer(ev, timer)</literal> sets a timeout for an
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2393 event, <literal>ngx_del_timer(ev)</literal> deletes a previously set timeout.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2394 Timeouts currently set for all existing events, are kept in a global timeout
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2395 Red-Black tree <literal>ngx_event_timer_rbtree</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2396 The key in that tree has the type <literal>ngx_msec_t</literal> and is the time
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2397 in milliseconds since the beginning of January 1, 1970 (modulus
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2398 <literal>ngx_msec_t</literal> max value) at which the event should expire.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2399 The tree structure provides fast inserting and deleting operations, as well as
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2400 accessing the nearest timeouts.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2401 The latter is used by nginx to find out for how long to wait for I/O events
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2402 and for expiring timeout events afterwards.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2403 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2404
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2405 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2406
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2407
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2408 <section name="Posted events" id="posted_events">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2409
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2410 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2411 An event can be posted which means that its handler will be called at some
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2412 point later within the current event loop iteration.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2413 Posting events is a good practice for simplifying code and escaping stack
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2414 overflows.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2415 Posted events are held in a post queue.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2416 The macro <literal>ngx_post_event(ev, q)</literal> posts the event
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2417 <literal>ev</literal> to the post queue <literal>q</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2418 Macro <literal>ngx_delete_posted_event(ev)</literal> deletes the event
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2419 <literal>ev</literal> from whatever queue it's currently posted.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2420 Normally, events are posted to the <literal>ngx_posted_events</literal> queue.
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2421 This queue is processed late in the event loop — after all I/O and timer
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2422 events are already handled.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2423 The function <literal>ngx_event_process_posted()</literal> is called to process
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2424 an event queue.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2425 This function calls event handlers until the queue is not empty. This means
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2426 that a posted event handler can post more events to be processed within the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2427 current event loop iteration.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2428 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2429
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2430 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2431 Example:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2432 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2433
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2434
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2435 <programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2436 void
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2437 ngx_my_connection_read(ngx_connection_t *c)
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2438 {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2439 ngx_event_t *rev;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2440
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2441 rev = c->read;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2442
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2443 ngx_add_timer(rev, 1000);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2444
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2445 rev->handler = ngx_my_read_handler;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2446
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2447 ngx_my_read(rev);
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2448 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2449
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2450
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2451 void
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2452 ngx_my_read_handler(ngx_event_t *rev)
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2453 {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2454 ssize_t n;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2455 ngx_connection_t *c;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2456 u_char buf[256];
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2457
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2458 if (rev->timedout) { /* timeout expired */ }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2459
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2460 c = rev->data;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2461
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2462 while (rev->ready) {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2463 n = c->recv(c, buf, sizeof(buf));
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2464
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2465 if (n == NGX_AGAIN) {
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2466 break;
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2467 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2468
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2469 if (n == NGX_ERROR) { /* error */ }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2470
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2471 /* process buf */
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2472 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2473
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2474 if (ngx_handle_read_event(rev, 0) != NGX_OK) { /* error */ }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2475 }
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2476 </programlisting>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2477
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2478 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2479
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2480
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2481 <section name="Event loop" id="event_loop">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2482
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2483 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2484 All nginx processes which do I/O, have an event loop.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2485 The only type of process which does not have I/O, is nginx master process which
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2486 spends most of its time in <literal>sigsuspend()</literal> call waiting for
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2487 signals to arrive.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2488 Event loop is implemented in <literal>ngx_process_events_and_timers()</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2489 function.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2490 This function is called repeatedly until the process exits.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2491 It has the following stages:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2492 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2493
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2494 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2495 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2496
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2497 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2498 find nearest timeout by calling <literal>ngx_event_find_timer()</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2499 This function finds the leftmost timer tree node and returns the number of
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2500 milliseconds until that node expires
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2501 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2502
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2503 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2504 process I/O events by calling a handler, specific to event notification
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2505 mechanism, chosen by nginx configuration.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2506 This handler waits for at least one I/O event to happen, but no longer, than
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2507 the nearest timeout.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2508 For each read or write event which has happened, the <literal>ready</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2509 flag is set and its handler is called.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2510 For Linux, normally, the <literal>ngx_epoll_process_events()</literal> handler
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2511 is used which calls <literal>epoll_wait()</literal> to wait for I/O events
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2512 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2513
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2514 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2515 expire timers by calling <literal>ngx_event_expire_timers()</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2516 The timer tree is iterated from the leftmost element to the right until a not
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2517 yet expired timeout is found.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2518 For each expired node the <literal>timedout</literal> event flag is set,
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2519 <literal>timer_set</literal> flag is reset, and the event handler is called
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2520 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2521
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2522 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2523 process posted events by calling <literal>ngx_event_process_posted()</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2524 The function repeatedly removes the first element from the posted events
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2525 queue and calls its handler until the queue gets empty
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2526 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2527
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2528 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2529 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2530
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2531 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2532 All nginx processes handle signals as well.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2533 Signal handlers only set global variables which are checked after the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2534 <literal>ngx_process_events_and_timers()</literal> call.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2535 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2536
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2537 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2538
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2539
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2540 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2541
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2542
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2543 <section name="Processes" id="processes">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2544
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2545 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2546 There are several types of processes in nginx.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2547 The type of current process is kept in the <literal>ngx_process</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2548 global variable:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2549 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2550
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2551 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2552
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2553 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2554
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2555 <para>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2556 <literal>NGX_PROCESS_MASTER</literal> — the master process runs the
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2557 <literal>ngx_master_process_cycle()</literal> function.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2558 Master process does not have any I/O and responds only to signals.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2559 It reads configuration, creates cycles, starts and controls child processes
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2560 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2561
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2562
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2563 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2564
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2565 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2566
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2567 <para>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2568 <literal>NGX_PROCESS_WORKER</literal> — the worker process runs the
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2569 <literal>ngx_worker_process_cycle()</literal> function.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2570 Worker processes are started by master and handle client connections.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2571 They also respond to signals and channel commands, sent from master
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2572 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2573
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2574
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2575 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2576
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2577 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2578
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2579 <para>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2580 <literal>NGX_PROCESS_SINGLE</literal> — single process is the only type
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2581 of processes which exist in the <literal>master_process off</literal> mode.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2582 The cycle function for this process is
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2583 <literal>ngx_single_process_cycle()</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2584 This process creates cycles and handles client connections
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2585 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2586
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2587
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2588 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2589
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2590 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2591
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2592 <para>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2593 <literal>NGX_PROCESS_HELPER</literal> — currently, there are two types of
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2594 helper processes: cache manager and cache loader.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2595 Both of them share the same cycle function
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2596 <literal>ngx_cache_manager_process_cycle()</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2597 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2598
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2599
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2600 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2601
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2602 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2603
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2604 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2605 All nginx processes handle the following signals:
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2606 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2607
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2608 <list type="bullet">
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2609
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2610 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2611
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2612 <para>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2613 <literal>NGX_SHUTDOWN_SIGNAL</literal> (<literal>SIGQUIT</literal>) — graceful
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2614 shutdown.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2615 Upon receiving this signal master process sends shutdown signal to all child
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2616 processes.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2617 When no child processes are left, master destroys cycle pool and exits.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2618 A worker process which received this signal, closes all listening sockets and
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2619 waits until timeout tree becomes empty, then destroys cycle pool and exits.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2620 A cache manager process exits right after receiving this signal.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2621 The variable <literal>ngx_quit</literal> is set to one after receiving this
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2622 signal and immediately reset after being processed.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2623 The variable <literal>ngx_exiting</literal> is set to one when worker process
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2624 is in shutdown state
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2625 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2626
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2627
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2628 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2629
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2630 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2631
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2632 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2633 <literal>NGX_TERMINATE_SIGNAL</literal> (<literal>SIGTERM</literal>) -
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2634 terminate.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2635 Upon receiving this signal master process sends terminate signal to all child
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2636 processes.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2637 If child processes do not exit in 1 second, they are killed with the
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2638 <literal>SIGKILL</literal> signal.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2639 When no child processes are left, master process destroys cycle pool and exits.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2640 A worker or cache manager process which received this signal destroys cycle
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2641 pool and exits.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2642 The variable <literal>ngx_terminate</literal> is set to one after receiving
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2643 this signal
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2644 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2645
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2646
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2647 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2648
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2649 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2650
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2651 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2652 <literal>NGX_NOACCEPT_SIGNAL</literal> (<literal>SIGWINCH</literal>)
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2653 - gracefully shut down worker processes
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2654 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2655
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2656
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2657 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2658
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2659 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2660
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2661 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2662 <literal>NGX_RECONFIGURE_SIGNAL</literal> (<literal>SIGHUP</literal>) -
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2663 reconfigure.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2664 Upon receiving this signal master process creates a new cycle from
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2665 configuration file.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2666 If the new cycle was created successfully, the old cycle is deleted and new
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2667 child processes are started.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2668 Meanwhile, the old processes receive the shutdown signal.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2669 In single-process mode, nginx creates a new cycle as well, but keeps the old
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2670 one until all clients, tied to the old cycle, are gone.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2671 Worker and helper processes ignore this signal
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2672 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2673
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2674
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2675 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2676
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2677 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2678
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2679 <para>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2680 <literal>NGX_REOPEN_SIGNAL</literal> (<literal>SIGUSR1</literal>) — reopen
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2681 files.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2682 Master process passes this signal to workers.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2683 Worker processes reopen all <literal>open_files</literal> from the cycle
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2684 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2685
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2686
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2687 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2688
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2689 <listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2690
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2691 <para>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2692 <literal>NGX_CHANGEBIN_SIGNAL</literal> (<literal>SIGUSR2</literal>) — change
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2693 nginx binary.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2694 Master process starts a new nginx binary and passes there a list of all listen
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2695 sockets.
1936
8f996938fe23 Style: proper quotes usage.
Vladimir Homutov <vl@nginx.com>
parents: 1935
diff changeset
2696 The list is passed in the environment variable <literal>“NGINX”</literal> in
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2697 text format, where descriptor numbers separated with semicolons.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2698 A new nginx instance reads that variable and adds the sockets to its init
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2699 cycle.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2700 Other processes ignore this signal
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2701 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2702
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2703
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2704 </listitem>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2705
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2706 </list>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2707
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2708 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2709 While all nginx worker processes are able to receive and properly handle POSIX
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2710 signals, master process normally does not pass any signals to workers and
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2711 helpers with the standard <literal>kill()</literal> syscall.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2712 Instead, nginx uses inter-process channels which allow sending messages between
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2713 all nginx processes.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2714 Currently, however, messages are only sent from master to its children.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2715 Those messages carry the same signals.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2716 The channels are socketpairs with their ends in different processes.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2717 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2718
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2719 <para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2720 When running nginx binary, several values can be specified next to
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2721 <literal>-s</literal> parameter.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2722 Those values are <literal>stop</literal>, <literal>quit</literal>,
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2723 <literal>reopen</literal>, <literal>reload</literal>.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2724 They are converted to signals <literal>NGX_TERMINATE_SIGNAL</literal>,
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2725 <literal>NGX_SHUTDOWN_SIGNAL</literal>, <literal>NGX_REOPEN_SIGNAL</literal>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2726 and <literal>NGX_RECONFIGURE_SIGNAL</literal> and sent to the nginx master
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2727 process, whose pid is read from nginx pid file.
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2728 </para>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2729
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2730 </section>
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
2731
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2732 <section name="Modules" id="Modules">
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2733
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2734 <section name="Adding new modules" id="adding_new_modules">
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2735 <para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2736 The standalone nginx module resides in a separate directory that contains
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2737 at least two files:
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2738 <literal>config</literal> and a file with the module source.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2739 The first file contains all information needed for nginx to integrate
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2740 the module, for example:
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2741 <programlisting>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2742 ngx_module_type=CORE
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2743 ngx_module_name=ngx_foo_module
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2744 ngx_module_srcs="$ngx_addon_dir/ngx_foo_module.c"
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2745
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2746 . auto/module
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2747
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2748 ngx_addon_name=$ngx_module_name
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2749 </programlisting>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2750 The file is a POSIX shell script and it can set (or access) the
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2751 following variables:
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2752 <list type="bullet">
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2753
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2754 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2755 <literal>ngx_module_type</literal> — the type of module to build.
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2756 Possible options are <literal>CORE</literal>, <literal>HTTP</literal>,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2757 <literal>HTTP_FILTER</literal>, <literal>HTTP_INIT_FILTER</literal>,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2758 <literal>HTTP_AUX_FILTER</literal>, <literal>MAIL</literal>,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2759 <literal>STREAM</literal>, or <literal>MISC</literal>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2760 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2761
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2762 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2763 <literal>ngx_module_name</literal> — the name of the module.
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2764 A whitespace separated values list is accepted and may be used to build
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2765 multiple modules from a single set of source files.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2766 The first name indicates the name of the output binary for a dynamic module.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2767 The names in this list should match the names used in the module.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2768 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2769
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2770 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2771 <literal>ngx_addon_name</literal> — supplies the name of the module in the
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2772 console output text of the configure script.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2773 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2774
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2775 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2776 <literal>ngx_module_srcs</literal> — a whitespace separated list of source
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2777 files used to compile the module.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2778 The $ngx_addon_dir variable can be used as a placeholder for the path of the
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2779 module source.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2780 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2781
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2782 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2783 <literal>ngx_module_incs</literal> — include paths required to build the module
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2784 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2785
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2786 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2787 <literal>ngx_module_deps</literal> — a list of module's header files.
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2788 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2789
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2790 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2791 <literal>ngx_module_libs</literal> — a list of libraries to link with the
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2792 module.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2793 For example, libpthread would be linked using
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2794 <literal>ngx_module_libs=-lpthread</literal>.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2795 The following macros can be used to link against the same libraries as
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2796 nginx:
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2797 <literal>LIBXSLT</literal>, <literal>LIBGD</literal>, <literal>GEOIP</literal>,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2798 <literal>PCRE</literal>, <literal>OPENSSL</literal>, <literal>MD5</literal>,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2799 <literal>SHA1</literal>, <literal>ZLIB</literal>, and <literal>PERL</literal>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2800 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2801
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2802 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2803 <literal>ngx_module_link</literal> — set by the build system to
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2804 <literal>DYNAMIC</literal> for a dynamic module or <literal>ADDON</literal>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2805 for a static module and used to perform different actions depending on
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2806 linking type.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2807 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2808
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2809 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
2810 <literal>ngx_module_order</literal> — sets the load order for the module which
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2811 is useful for <literal>HTTP_FILTER</literal> and
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2812 <literal>HTTP_AUX_FILTER</literal> module types.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2813 The order is stored in a reverse list.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2814
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2815 <para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2816 The <literal>ngx_http_copy_filter_module</literal> is near the bottom of the
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2817 list so is one of the first to be executed.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2818 This reads the data for other filters.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2819 Near the top of the list is <literal>ngx_http_write_filter_module</literal>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2820 which writes the data out and is one of the last to be executed.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2821 </para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2822
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2823 <para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2824 The format for this option is typically the current module’s name followed by
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2825 a whitespace separated list of modules to insert before, and therefore execute
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2826 after.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2827 The module will be inserted before the last module in the list that is found
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2828 to be currently loaded.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2829 </para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2830
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2831 <para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2832 By default for filter modules this is set to
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2833 “<literal>ngx_http_copy_filter</literal>” which will insert the module before
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2834 the copy filter in the list and therefore will execute after the copy filter.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2835 For other module types the default is empty.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2836 </para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2837
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2838 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2839
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2840 </list>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2841
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2842 A module can be added to nginx by means of the configure script using
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2843 <literal>--add-module=/path/to/module</literal> for static compilation and
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2844 <literal>--add-dynamic-module=/path/to/module</literal> for dynamic compilation.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2845 </para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2846
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2847 </section>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2848
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2849
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2850 <section name="Core modules" id="core_modules">
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2851
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2852 <para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2853 Modules are building blocks of nginx, and most of its functionality is
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2854 implemented as modules.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2855 The module source file must contain a global variable of
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2856 <literal>ngx_module_t</literal> type which is defined as follows:
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2857 <programlisting>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2858 struct ngx_module_s {
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2859
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2860 /* private part is omitted */
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2861
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2862 void *ctx;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2863 ngx_command_t *commands;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2864 ngx_uint_t type;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2865
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2866 ngx_int_t (*init_master)(ngx_log_t *log);
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2867
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2868 ngx_int_t (*init_module)(ngx_cycle_t *cycle);
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2869
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2870 ngx_int_t (*init_process)(ngx_cycle_t *cycle);
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2871 ngx_int_t (*init_thread)(ngx_cycle_t *cycle);
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2872 void (*exit_thread)(ngx_cycle_t *cycle);
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2873 void (*exit_process)(ngx_cycle_t *cycle);
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2874
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2875 void (*exit_master)(ngx_cycle_t *cycle);
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2876
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2877 /* stubs for future extensions are omitted */
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2878 };
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2879 </programlisting>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2880 The omitted private part includes module version, signature and is filled
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2881 using the predefined macro <literal>NGX_MODULE_V1</literal>.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2882 </para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2883
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2884 <para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2885 Each module keeps its private data in the <literal>ctx</literal> field,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2886 recognizes specific configuration directives, specified in the
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2887 <literal>commands</literal> array, and may be invoked at certain stages of
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2888 nginx lifecycle.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2889 The module lifecycle consists of the following events:
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2890
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2891 <list type="bullet">
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2892
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2893 <listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2894 Configuration directive handlers are called as they appear
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2895 in configuration files in the context of the master process
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2896 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2897
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2898 <listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2899 The <literal>init_module</literal> handler is called in the context of
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2900 the master process after the configuration is parsed successfully
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2901 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2902
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2903 <listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2904 The master process creates worker process(es) and
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2905 <literal>init_process</literal> handler is called in each of them
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2906 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2907
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2908 <listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2909 When a worker process receives the shutdown command from master, it invokes
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2910 the <literal>exit_process</literal> handler
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2911 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2912
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2913 <listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2914 The master process calls the <literal>exit_master</literal> handler before
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2915 exiting.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2916 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2917
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2918 </list>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2919
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2920 <note>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2921 <literal>init_module</literal> handler may be called multiple times
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2922 in the master process if the configuration reload is requested.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2923 </note>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2924
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2925 The <literal>init_master</literal>, <literal>init_thread</literal> and
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2926 <literal>exit_thread</literal> handlers are not implemented at the moment;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2927 Threads in nginx are only used as supplementary I/O facility with its own
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2928 API and <literal>init_master</literal> handler looks unnecessary.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2929 </para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2930
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2931 <para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2932 The module <literal>type</literal> defines what exactly is stored in the
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2933 <literal>ctx</literal> field.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2934 There are several types of modules:
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2935 <list type="bullet">
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2936 <listitem><literal>NGX_CORE_MODULE</literal></listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2937 <listitem><literal>NGX_EVENT_MODULE</literal></listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2938 <listitem><literal>NGX_HTTP_MODULE</literal></listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2939 <listitem><literal>NGX_MAIL_MODULE</literal></listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2940 <listitem><literal>NGX_STREAM_MODULE</literal></listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2941 </list>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2942 The <literal>NGX_CORE_MODULE</literal> is the most basic and thus the most
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2943 generic and most low-level type of module. Other module types are implemented
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2944 on top of it and provide more convenient way to deal with corresponding
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2945 problem domains, like handling events or http requests.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2946 </para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2947
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2948 <para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2949 The examples of core modules are <literal>ngx_core_module</literal>,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2950 <literal>ngx_errlog_module</literal>, <literal>ngx_regex_module</literal>,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2951 <literal>ngx_thread_pool_module</literal>,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2952 <literal>ngx_openssl_module</literal>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2953 modules and, of course, http, stream, mail and event modules itself.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2954 The context of a core module is defined as:
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2955 <programlisting>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2956 typedef struct {
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2957 ngx_str_t name;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2958 void *(*create_conf)(ngx_cycle_t *cycle);
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2959 char *(*init_conf)(ngx_cycle_t *cycle, void *conf);
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2960 } ngx_core_module_t;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2961 </programlisting>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2962 where the <literal>name</literal> is a string with a module name for
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2963 convenience, <literal>create_conf</literal> and <literal>init_conf</literal>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2964 are pointers to functions that create and initialize module configuration
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2965 correspondingly.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2966 For core modules, nginx will call <literal>create_conf</literal> before parsing
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2967 a new configuration and <literal>init_conf</literal> after all configuration
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2968 was parsed successfully.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2969 The typical <literal>create_conf</literal> function allocates memory for the
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2970 configuration and sets default values.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2971 The <literal>init_conf</literal> deals with known configuration and thus may
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2972 perform sanity checks and complete initialization.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2973 </para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2974
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2975 <para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2976 For example, the simplistic <literal>ngx_foo_module</literal> can look like
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2977 this:
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2978 <programlisting>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2979 /*
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2980 * Copyright (C) Author.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2981 */
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2982
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2983
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2984 #include &lt;ngx_config.h&gt;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2985 #include &lt;ngx_core.h&gt;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2986
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2987
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2988 typedef struct {
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2989 ngx_flag_t enable;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2990 } ngx_foo_conf_t;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2991
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2992
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2993 static void *ngx_foo_create_conf(ngx_cycle_t *cycle);
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2994 static char *ngx_foo_init_conf(ngx_cycle_t *cycle, void *conf);
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2995
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2996 static char *ngx_foo_enable(ngx_conf_t *cf, void *post, void *data);
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2997 static ngx_conf_post_t ngx_foo_enable_post = { ngx_foo_enable };
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2998
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
2999
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3000 static ngx_command_t ngx_foo_commands[] = {
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3001
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3002 { ngx_string("foo_enabled"),
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3003 NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_FLAG,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3004 ngx_conf_set_flag_slot,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3005 0,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3006 offsetof(ngx_foo_conf_t, enable),
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3007 &amp;ngx_foo_enable_post },
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3008
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3009 ngx_null_command
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3010 };
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3011
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3012
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3013 static ngx_core_module_t ngx_foo_module_ctx = {
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3014 ngx_string("foo"),
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3015 ngx_foo_create_conf,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3016 ngx_foo_init_conf
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3017 };
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3018
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3019
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3020 ngx_module_t ngx_foo_module = {
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3021 NGX_MODULE_V1,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3022 &amp;ngx_foo_module_ctx, /* module context */
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3023 ngx_foo_commands, /* module directives */
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3024 NGX_CORE_MODULE, /* module type */
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3025 NULL, /* init master */
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3026 NULL, /* init module */
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3027 NULL, /* init process */
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3028 NULL, /* init thread */
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3029 NULL, /* exit thread */
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3030 NULL, /* exit process */
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3031 NULL, /* exit master */
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3032 NGX_MODULE_V1_PADDING
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3033 };
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3034
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3035
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3036 static void *
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3037 ngx_foo_create_conf(ngx_cycle_t *cycle)
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3038 {
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3039 ngx_foo_conf_t *fcf;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3040
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3041 fcf = ngx_pcalloc(cycle->pool, sizeof(ngx_foo_conf_t));
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3042 if (fcf == NULL) {
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3043 return NULL;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3044 }
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3045
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3046 fcf->enable = NGX_CONF_UNSET;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3047
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3048 return fcf;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3049 }
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3050
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3051
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3052 static char *
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3053 ngx_foo_init_conf(ngx_cycle_t *cycle, void *conf)
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3054 {
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3055 ngx_foo_conf_t *fcf = conf;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3056
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3057 ngx_conf_init_value(fcf->enable, 0);
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3058
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3059 return NGX_CONF_OK;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3060 }
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3061
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3062
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3063 static char *
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3064 ngx_foo_enable(ngx_conf_t *cf, void *post, void *data)
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3065 {
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3066 ngx_flag_t *fp = data;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3067
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3068 if (*fp == 0) {
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3069 return NGX_CONF_OK;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3070 }
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3071
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3072 ngx_log_error(NGX_LOG_NOTICE, cf->log, 0, "Foo Module is enabled");
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3073
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3074 return NGX_CONF_OK;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3075 }
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3076 </programlisting>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3077 </para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3078
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3079 </section>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3080
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3081
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3082 <section name="Configuration directives" id="config_directives">
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3083
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3084 <para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3085 The <literal>ngx_command_t</literal> describes single configuration directive.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3086 Each module, supporting configuration, provides an array of such specifications
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3087 that describe how to process arguments and what handlers to call:
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3088 <programlisting>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3089 struct ngx_command_s {
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3090 ngx_str_t name;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3091 ngx_uint_t type;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3092 char *(*set)(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3093 ngx_uint_t conf;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3094 ngx_uint_t offset;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3095 void *post;
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3096 };
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3097 </programlisting>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3098 The array should be terminated by a special value
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3099 “<literal>ngx_null_command</literal>”.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3100 The <literal>name</literal> is the literal name of a directive, as it appears
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3101 in configuration file, for example “<literal>worker_processes</literal>” or
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3102 “<literal>listen</literal>”.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3103 The <literal>type</literal> is a bitfield that controls number of arguments,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3104 command type and other properties using corresponding flags.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3105 Arguments flags:
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3106
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3107 <list type="bullet">
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3108
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3109 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3110 <literal>NGX_CONF_NOARGS</literal> — directive without arguments
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3111 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3112
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3113 <listitem><literal>NGX_CONF_1MORE</literal> — one required argument</listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3114
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3115 <listitem><literal>NGX_CONF_2MORE</literal> — two required arguments</listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3116
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3117 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3118 <literal>NGX_CONF_TAKE1..7</literal> — exactly 1..7 arguments
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3119 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3120
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3121 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3122 <literal>NGX_CONF_TAKE12, 13, 23, 123, 1234</literal> — one or two arguments,
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3123 or other combinations
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3124 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3125
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3126 </list>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3127
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3128 Directive types:
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3129
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3130 <list type="bullet">
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3131
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3132 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3133 <literal>NGX_CONF_BLOCK</literal> — the directive is a block, i.e. it may
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3134 contain other directives in curly braces, or even implement its own parser
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3135 to handle contents inside.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3136 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3137
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3138 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3139 <literal>NGX_CONF_FLAG</literal> — the directive value is a flag, a boolean
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3140 value represented by “<literal>on</literal>” or “<literal>off</literal>”
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3141 strings.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3142 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3143 </list>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3144
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3145 Context of a directive defines where in the configuration it may appear
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3146 and how to access module context to store corresponding values:
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3147 <list type="bullet">
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3148
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3149 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3150 <literal>NGX_MAIN_CONF</literal> — top level configuration
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3151 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3152
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3153 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3154 <literal>NGX_HTTP_MAIN_CONF</literal> — in the http block
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3155 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3156
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3157 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3158 <literal>NGX_HTTP_SRV_CONF</literal> — in the http server block
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3159 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3160
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3161 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3162 <literal>NGX_HTTP_LOC_CONF</literal> — in the http location
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3163 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3164
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3165 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3166 <literal>NGX_HTTP_UPS_CONF</literal> — in the http upstream block
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3167 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3168
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3169 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3170 <literal>NGX_HTTP_SIF_CONF</literal> — in the http server “if”
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3171 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3172
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3173 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3174 <literal>NGX_HTTP_LIF_CONF</literal> — in the http location “if”
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3175 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3176
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3177 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3178 <literal>NGX_HTTP_LMT_CONF</literal> — in the http “limit_except”
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3179 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3180
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3181 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3182 <literal>NGX_STREAM_MAIN_CONF</literal> — in the stream block
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3183 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3184
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3185 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3186 <literal>NGX_STREAM_SRV_CONF</literal> — in the stream server block
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3187 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3188
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3189 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3190 <literal>NGX_STREAM_UPS_CONF</literal> — in the stream upstream block
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3191 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3192
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3193 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3194 <literal>NGX_MAIL_MAIN_CONF</literal> — in the the mail block
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3195 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3196
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3197 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3198 <literal>NGX_MAIL_SRV_CONF</literal> — in the mail server block
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3199 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3200
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3201 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3202 <literal>NGX_EVENT_CONF</literal> — in the event block
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3203 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3204
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3205 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3206 <literal>NGX_DIRECT_CONF</literal> — used by modules that don't
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3207 create a hierarchy of contexts and store module configuration directly in ctx
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3208 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3209 </list>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3210 The configuration parser uses this flags to throw an error in case of
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3211 a misplaced directive and calls directive handlers supplied with a proper
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3212 configuration pointer, so that same directives in different locations could
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3213 store their values in distinct places.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3214 </para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3215
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3216 <para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3217 The <literal>set</literal> field defines a handler that processes a directive
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3218 and stores parsed values into corresponding configuration.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3219 Nginx offers a convenient set of functions that perform common conversions:
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3220
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3221 <list type="bullet">
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3222
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3223 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3224 <literal>ngx_conf_set_flag_slot</literal> — converts literal
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3225 “<literal>on</literal>” or “<literal>off</literal>” strings into
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3226 <literal>ngx_flag_t</literal> type with values 1 or 0
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3227 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3228
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3229 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3230 <literal>ngx_conf_set_str_slot</literal> — stores string as a value of the
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3231 <literal>ngx_str_t</literal> type
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3232 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3233
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3234 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3235 <literal>ngx_conf_set_str_array_slot</literal> — appends
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3236 <literal>ngx_array_t</literal> of <literal>ngx_str_t</literal> with a new value.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3237 The array is created if not yet exists
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3238 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3239
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3240 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3241 <literal>ngx_conf_set_keyval_slot</literal> — appends
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3242 <literal>ngx_array_t</literal> of <literal>ngx_keyval_t</literal> with
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3243 a new value, where key is the first string and value is second.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3244 The array is created if not yet exists
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3245 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3246
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3247 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3248 <literal>ngx_conf_set_num_slot</literal> — converts directive argument
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3249 to a <literal>ngx_int_t</literal> value
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3250 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3251
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3252 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3253 <literal>ngx_conf_set_size_slot</literal> — converts
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3254 <link doc="../syntax.xml">size</link> to <literal>size_t</literal> value
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3255 in bytes
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3256 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3257
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3258 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3259 <literal>ngx_conf_set_off_slot</literal> — converts
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3260 <link doc="../syntax.xml">offset</link> to <literal>off_t</literal> value
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3261 in bytes
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3262 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3263
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3264 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3265 <literal>ngx_conf_set_msec_slot</literal> — converts
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3266 <link doc="../syntax.xml">time</link> to <literal>ngx_msec_t</literal> value
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3267 in milliseconds
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3268 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3269
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3270 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3271 <literal>ngx_conf_set_sec_slot</literal> — converts
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3272 <link doc="../syntax.xml">time</link> to <literal>time_t</literal> value
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3273 in seconds
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3274 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3275
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3276 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3277 <literal>ngx_conf_set_bufs_slot</literal> — converts two arguments
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3278 into <literal>ngx_bufs_t</literal> that holds <literal>ngx_int_t</literal>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3279 number and <link doc="../syntax.xml">size</link> of buffers
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3280 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3281
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3282 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3283 <literal>ngx_conf_set_enum_slot</literal> — converts argument
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3284 into <literal>ngx_uint_t</literal> value.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3285 The null-terminated array of <literal>ngx_conf_enum_t</literal> passed in the
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3286 <literal>post</literal> field defines acceptable strings and corresponding
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3287 integer values
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3288 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3289
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3290 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3291 <literal>ngx_conf_set_bitmask_slot</literal> — arguments are converted to
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3292 <literal>ngx_uint_t</literal> value and OR'ed with the resulting value,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3293 forming a bitmask.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3294 The null-terminated array of <literal>ngx_conf_bitmask_t</literal> passed in
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3295 the <literal>post</literal> field defines acceptable strings and corresponding
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3296 mask values
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3297 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3298
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3299 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3300 <literal>set_path_slot</literal> — converts arguments to
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3301 <literal>ngx_path_t</literal> type and performs all required initializations.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3302 See the
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3303 <link doc="../http/ngx_http_proxy_module.xml" id="proxy_temp_path">proxy_temp_path</link>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3304 directive description for details
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3305 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3306
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3307 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3308 <literal>set_access_slot</literal> — converts arguments to file permissions
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3309 mask.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3310 See the
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3311 <link doc="../http/ngx_http_proxy_module.xml" id="proxy_store_access">proxy_store_access</link>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3312 directive description for details
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3313 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3314
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3315 </list>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3316
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3317 </para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3318
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3319 <para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3320 The <literal>conf</literal> field defines which context is used to store
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3321 the value of the directive, or zero if contexts are not used.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3322 Only simple core modules use configuration without context and set
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3323 <literal>NGX_DIRECT_CONF</literal> flag.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3324 In real life, such modules like http or stream require more sophisticated
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3325 configuration that can be applied per-server or per-location, or even more
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3326 precisely, in the context of the “<literal>if</literal>” directive or
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3327 some limit.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3328 In this modules, configuration structure is more complex.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3329 Please refer to corresponding modules description to understand how
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3330 they manage their configuration.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3331
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3332 <list type="bullet">
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3333 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3334 <literal>NGX_HTTP_MAIN_CONF_OFFSET</literal> — http block configuration
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3335 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3336
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3337 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3338 <literal>NGX_HTTP_SRV_CONF_OFFSET</literal> — http server configuration
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3339 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3340
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3341 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3342 <literal>NGX_HTTP_LOC_CONF_OFFSET</literal> — http location configuration
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3343 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3344
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3345 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3346 <literal>NGX_STREAM_MAIN_CONF_OFFSET</literal> — stream block configuration
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3347 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3348
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3349 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3350 <literal>NGX_STREAM_SRV_CONF_OFFSET</literal> — stream server configuration
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3351 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3352
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3353 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3354 <literal>NGX_MAIL_MAIN_CONF_OFFSET</literal> — mail block configuration
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3355 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3356
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3357 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3358 <literal>NGX_MAIL_SRV_CONF_OFFSET</literal> — mail server configuration
1928
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3359 </listitem>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3360
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3361 </list>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3362
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3363 </para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3364
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3365 <para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3366 The <literal>offset</literal> defines an offset of a field in a module
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3367 configuration structure that holds values of this particular directive.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3368 The typical use is to employ <literal>offsetof()</literal> macro.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3369 </para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3370
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3371 <para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3372 The <literal>post</literal> is a twofold field: it may be used to define
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3373 a handler to be called after main handler completed or to pass additional
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3374 data to the main handler.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3375 In the first case, <literal>ngx_conf_post_t</literal> structure needs to
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3376 be initialized with a pointer to handler, for example:
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3377 <programlisting>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3378 static char *ngx_do_foo(ngx_conf_t *cf, void *post, void *data);
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3379 static ngx_conf_post_t ngx_foo_post = { ngx_do_foo };
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3380 </programlisting>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3381 The <literal>post</literal> argument is the <literal>ngx_conf_post_t</literal>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3382 object itself, and the <literal>data</literal> is a pointer to value,
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3383 converted from arguments by the main handler with the appropriate type.
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3384 </para>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3385
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3386 </section>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3387
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3388 </section>
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3389
2c14a16c61eb Added modules section to development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1920
diff changeset
3390
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3391 <section name="HTTP" id="http">
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3392
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3393
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3394 <section name="Connection" id="http_connection">
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3395
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3396 <para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3397 Each client HTTP connection runs through the following stages:
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3398 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3399
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3400 <list type="bullet">
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3401
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3402 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3403 <literal>ngx_event_accept()</literal> accepts a client TCP connection.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3404 This handler is called in response to a read notification on a listen socket.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3405 A new <literal>ngx_connecton_t</literal> object is created at this stage.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3406 The object wraps the newly accepted client socket.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3407 Each nginx listener provides a handler to pass the new connection object to.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3408 For HTTP connections it's <literal>ngx_http_init_connection(c)</literal>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3409 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3410
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3411 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3412 <literal>ngx_http_init_connection()</literal> performs early initialization of
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3413 an HTTP connection.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3414 At this stage an <literal>ngx_http_connection_t</literal> object is created for
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3415 the connection and its reference is stored in connection's
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3416 <literal>data</literal> field.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3417 Later it will be substituted with an HTTP request object.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3418 PROXY protocol parser and SSL handshake are started at this stage as well
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3419 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3420
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3421 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3422 <literal>ngx_http_wait_request_handler()</literal> is a read event handler, that
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3423 is called when data is available in the client socket.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3424 At this stage an HTTP request object <literal>ngx_http_request_t</literal> is
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3425 created and set to connection's <literal>data</literal> field
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3426 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3427
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3428 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3429 <literal>ngx_http_process_request_line()</literal> is a read event handler,
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3430 which reads client request line.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3431 The handler is set by <literal>ngx_http_wait_request_handler()</literal>.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3432 Reading is done into connection's <literal>buffer</literal>.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3433 The size of the buffer is initially set by the directive
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3434 <link doc="../http/ngx_http_core_module.xml" id="client_header_buffer_size"/>.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3435 The entire client header is supposed to fit the buffer.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3436 If the initial size is not enough, a bigger buffer is allocated, whose size is
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3437 set by the <literal>large_client_header_buffers</literal> directive
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3438 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3439
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3440 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3441 <literal>ngx_http_process_request_headers()</literal> is a read event handler,
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3442 which is set after <literal>ngx_http_process_request_line()</literal> to read
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3443 client request header
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3444 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3445
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3446 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3447 <literal>ngx_http_core_run_phases()</literal> is called when the request header
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3448 is completely read and parsed.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3449 This function runs request phases from
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3450 <literal>NGX_HTTP_POST_READ_PHASE</literal> to
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3451 <literal>NGX_HTTP_CONTENT_PHASE</literal>.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3452 The last phase is supposed to generate response and pass it along the filter
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3453 chain.
1979
ff28ca78bef3 Fixed a typo.
Vladimir Homutov <vl@nginx.com>
parents: 1976
diff changeset
3454 The response is not necessarily sent to the client at this phase.
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3455 It may remain buffered and will be sent at the finalization stage
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3456 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3457
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3458 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3459 <literal>ngx_http_finalize_request()</literal> is usually called when the
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3460 request has generated all the output or produced an error.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3461 In the latter case an appropriate error page is looked up and used as the
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3462 response.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3463 If the response is not completely sent to the client by this point, an
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3464 HTTP writer <literal>ngx_http_writer()</literal> is activated to finish
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3465 sending outstanding data
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3466 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3467
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3468 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3469 <literal>ngx_http_finalize_connection()</literal> is called when the response is
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3470 completely sent to the client and the request can be destroyed.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3471 If client connection keepalive feature is enabled,
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3472 <literal>ngx_http_set_keepalive()</literal> is called, which destroys current
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3473 request and waits for the next request on the connection.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3474 Otherwise, <literal>ngx_http_close_request()</literal> destroys both the
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3475 request and the connection
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3476 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3477
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3478 </list>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3479
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3480 </section>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3481
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3482
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3483 <section name="Request" id="http_request">
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3484
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3485 <para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3486 For each client HTTP request the <literal>ngx_http_request_t</literal> object is
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3487 created. Some of the fields of this object:
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3488 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3489
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3490 <list type="bullet">
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3491
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3492 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3493
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3494 <para>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3495 <literal>connection</literal> — pointer to a <literal>ngx_connection_t</literal>
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3496 client connection object.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3497 Several requests may reference the same connection object at the same time -
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3498 one main request and its subrequests.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3499 After a request is deleted, a new request may be created on the same connection.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3500 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3501
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3502 <para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3503 Note that for HTTP connections <literal>ngx_connection_t</literal>'s
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3504 <literal>data</literal> field points back to the request.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3505 Such request is called active, as opposed to the other requests tied with the
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3506 connection.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3507 Active request is used to handle client connection events and is allowed to
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3508 output its response to the client.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3509 Normally, each request becomes active at some point to be able to send its
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3510 output
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3511 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3512
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3513 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3514
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3515 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3516
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3517 <para>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3518 <literal>ctx</literal> — array of HTTP module contexts.
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3519 Each module of type <literal>NGX_HTTP_MODULE</literal> can store any value
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3520 (normally, a pointer to a structure) in the request.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3521 The value is stored in the <literal>ctx</literal> array at the module's
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3522 <literal>ctx_index</literal> position.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3523 The following macros provide a convenient way to get and set request contexts:
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3524 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3525
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3526 <list type="bullet">
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3527
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3528 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3529 <literal>ngx_http_get_module_ctx(r, module)</literal> — returns
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3530 <literal>module</literal>'s context
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3531 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3532
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3533 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3534 <literal>ngx_http_set_ctx(r, c, module)</literal> — sets <literal>c</literal>
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3535 as <literal>module</literal>'s context
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3536 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3537
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3538 </list>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3539
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3540 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3541
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3542 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3543 <literal>main_conf, srv_conf, loc_conf</literal> — arrays of current request
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3544 configurations.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3545 Configurations are stored at module's <literal>ctx_index</literal> positions
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3546 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3547
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3548 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3549 <literal>read_event_handler</literal>, <literal>write_event_handler</literal> -
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3550 read and write event handlers for the request.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3551 Normally, an HTTP connection has <literal>ngx_http_request_handler()</literal>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3552 set as both read and write event handlers.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3553 This function calls <literal>read_event_handler</literal> and
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3554 <literal>write_event_handler</literal> handlers of the currently active request
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3555 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3556
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3557 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3558 <literal>cache</literal> — request cache object for caching upstream response
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3559 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3560
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3561 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3562 <literal>upstream</literal> — request upstream object for proxying
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3563 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3564
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3565 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3566 <literal>pool</literal> — request pool.
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3567 This pool is destroyed when the request is deleted.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3568 The request object itself is allocated in this pool.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3569 For allocations which should be available throughout the client connection's
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3570 lifetime, <literal>ngx_connection_t</literal>'s pool should be used instead
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3571 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3572
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3573 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3574 <literal>header_in</literal> — buffer where client HTTP request header in read
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3575 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3576
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3577 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3578 <literal>headers_in, headers_out</literal> — input and output HTTP headers
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3579 objects.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3580 Both objects contain the <literal>headers</literal> field of type
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3581 <literal>ngx_list_t</literal> keeping the raw list of headers.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3582 In addition to that, specific headers are available for getting and setting as
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3583 separate fields, for example <literal>content_length_n</literal>,
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3584 <literal>status</literal> etc
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3585 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3586
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3587 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3588 <literal>request_body</literal> — client request body object
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3589 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3590
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3591 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3592 <literal>start_sec, start_msec</literal> — time point when the request was
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3593 created.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3594 Used for tracking request duration
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3595 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3596
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3597 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3598 <literal>method, method_name</literal> — numeric and textual representation of
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3599 client HTTP request method.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3600 Numeric values for methods are defined in
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3601 <literal>src/http/ngx_http_request.h</literal> with macros
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3602 <literal>NGX_HTTP_GET, NGX_HTTP_HEAD, NGX_HTTP_POST</literal> etc
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3603 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3604
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3605 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3606 <literal>http_protocol, http_version, http_major, http_minor</literal> -
1936
8f996938fe23 Style: proper quotes usage.
Vladimir Homutov <vl@nginx.com>
parents: 1935
diff changeset
3607 client HTTP protocol version in its original textual form (“HTTP/1.0”,
8f996938fe23 Style: proper quotes usage.
Vladimir Homutov <vl@nginx.com>
parents: 1935
diff changeset
3608 “HTTP/1.1” etc), numeric form (<literal>NGX_HTTP_VERSION_10</literal>,
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3609 <literal>NGX_HTTP_VERSION_11</literal> etc) and separate major and minor
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3610 versions
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3611 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3612
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3613 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3614 <literal>request_line, unparsed_uri</literal> — client original request line
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3615 and URI
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3616 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3617
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3618 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3619 <literal>uri, args, exten</literal> — current request URI, arguments and file
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3620 extention.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3621 The URI value here might differ from the original URI sent by the client due to
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3622 normalization.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3623 Throughout request processing, these value can change while performing internal
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3624 redirects
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3625 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3626
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3627 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3628 <literal>main</literal> — pointer to a main request object.
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3629 This object is created to process client HTTP request, as opposed to
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3630 subrequests, created to perform a specific sub-task within the main request
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3631 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3632
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3633 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3634 <literal>parent</literal> — pointer to a parent request of a subrequest
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3635 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3636
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3637 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3638 <literal>postponed</literal> — list of output buffers and subrequests in the
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3639 order they are sent and created.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3640 The list is used by the postpone filter to provide consistent request output,
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3641 when parts of it are created by subrequests
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3642 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3643
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3644 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3645 <literal>post_subrequest</literal> — pointer to a handler with context to be
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3646 called when a subrequest gets finalized.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3647 Unused for main requests
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3648 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3649
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3650 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3651
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3652 <para>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3653 <literal>posted_requests</literal> — list of requests to be started or
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3654 resumed.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3655 Starting or resuming is done by calling the request's
1932
937e03180281 Fixed trailing spaces.
Vladimir Homutov <vl@nginx.com>
parents: 1929
diff changeset
3656 <literal>write_event_handler</literal>.
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3657 Normally, this handler holds the request main function, which at first runs
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3658 request phases and then produces the output.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3659 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3660
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3661 <para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3662 A request is usually posted by the
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3663 <literal>ngx_http_post_request(r, NULL)</literal> call.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3664 It is always posted to the main request <literal>posted_requests</literal> list.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3665 The function <literal>ngx_http_run_posted_requests(c)</literal> runs all
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3666 requests, posted in the main request of the passed connection's active request.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3667 This function should be called in all event handlers, which can lead to new
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3668 posted requests.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3669 Normally, it's called always after invoking a request's read or write handler
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3670 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3671
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3672 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3673
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3674 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3675 <literal>phase_handler</literal> — index of current request phase
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3676 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3677
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3678 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3679 <literal>ncaptures, captures, captures_data</literal> — regex captures produced
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3680 by the last regex match of the request.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3681 While processing a request, there's a number of places where a regex match can
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3682 happen: map lookup, server lookup by SNI or HTTP Host, rewrite, proxy_redirect
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3683 etc.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3684 Captures produced by a lookup are stored in the above mentioned fields.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3685 The field <literal>ncaptures</literal> holds the number of captures,
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3686 <literal>captures</literal> holds captures boundaries,
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3687 <literal>captures_data</literal> holds a string, against which the regex was
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3688 matched and which should be used to extract captures.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3689 After each new regex match request captures are reset to hold new values
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3690 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3691
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3692 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3693 <literal>count</literal> — request reference counter.
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3694 The field only makes sense for the main request.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3695 Increasing the counter is done by simple <literal>r->main->count++</literal>.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3696 To decrease the counter <literal>ngx_http_finalize_request(r, rc)</literal>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3697 should be called.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3698 Creation of a subrequest or running request body read process increase the
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3699 counter
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3700 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3701
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3702 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3703 <literal>subrequests</literal> — current subrequest nesting level.
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3704 Each subrequest gets the nesting level of its parent decreased by one.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3705 Once the value reaches zero an error is generated.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3706 The value for the main request is defined by the
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3707 <literal>NGX_HTTP_MAX_SUBREQUESTS</literal> constant
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3708 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3709
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3710 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3711 <literal>uri_changes</literal> — number of URI changes left for the request.
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3712 The total number of times a request can change its URI is limited by the
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3713 <literal>NGX_HTTP_MAX_URI_CHANGES</literal> constant.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3714 With each change the value is decreased until it reaches zero.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3715 In the latter case an error is generated.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3716 The actions considered as URI changes are rewrites and internal redirects to
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3717 normal or named locations
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3718 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3719
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3720 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3721 <literal>blocked</literal> — counter of blocks held on the request.
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3722 While this value is non-zero, request cannot be terminated.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3723 Currently, this value is increased by pending AIO operations (POSIX AIO and
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3724 thread operations) and active cache lock
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3725 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3726
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3727 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3728 <literal>buffered</literal> — bitmask showing which modules have buffered the
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3729 output produced by the request.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3730 A number of filters can buffer output, for example sub_filter can buffer data
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3731 due to a partial string match, copy filter can buffer data because of the lack
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3732 of free output_buffers etc.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3733 As long as this value is non-zero, request is not finalized, expecting the flush
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3734 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3735
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3736 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3737 <literal>header_only</literal> — flag showing that output does not require body.
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3738 For example, this flag is used by HTTP HEAD requests
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3739 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3740
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3741 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3742 <para>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3743 <literal>keepalive</literal> — flag showing if client connection keepalive is
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3744 supported.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3745 The value is inferred from HTTP version and <header>Connection</header> header
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3746 value
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3747 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3748 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3749
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3750 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3751 <literal>header_sent</literal> — flag showing that output header has already
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3752 been sent by the request
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3753 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3754
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3755 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3756 <literal>internal</literal> — flag showing that current request is internal.
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3757 To enter the internal state, a request should pass through an internal
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3758 redirect or be a subrequest.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3759 Internal requests are allowed to enter internal locations
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3760 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3761
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3762 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3763 <literal>allow_ranges</literal> — flag showing that partial response can be
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3764 sent to client, if requested by the HTTP Range header
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3765 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3766
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3767 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3768 <literal>subrequest_ranges</literal> — flag showing that a partial response is
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3769 allowed to be sent while processing a subrequest
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3770 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3771
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3772 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3773 <literal>single_range</literal> — flag showing that only a single continuous
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3774 range of output data can be sent to the client.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3775 This flag is usually set when sending a stream of data, for example from a
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3776 proxied server, and the entire response is not available at once
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3777 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3778
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3779 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3780 <literal>main_filter_need_in_memory, filter_need_in_memory</literal> — flags
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3781 showing that the output should be produced in memory buffers but not in files.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3782 This is a signal to the copy filter to read data from file buffers even if
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3783 sendfile is enabled.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3784 The difference between these two flags is the location of filter modules which
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3785 set them.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3786 Filters called before the postpone filter in filter chain, set
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3787 <literal>filter_need_in_memory</literal> requesting that only the current
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3788 request output should come in memory buffers.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3789 Filters called later in filter chain set
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3790 <literal>main_filter_need_in_memory</literal> requiring that both the main
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3791 request and all the subrequest read files in memory while sending output
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3792 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3793
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3794 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
3795 <literal>filter_need_temporary</literal> — flag showing that the request output
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3796 should be produced in temporary buffers, but not in readonly memory buffers or
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3797 file buffers.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3798 This is used by filters which may change output directly in the buffers, where
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3799 it's sent </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3800
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3801 </list>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3802
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3803 </section>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3804
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3805
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3806 <section name="Configuration" id="http_conf">
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3807
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3808 <para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3809 Each HTTP module may have three types of configuration:
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3810 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3811
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3812 <list type="bullet">
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3813
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3814 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3815 Main configuration.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3816 This configuration applies to the entire nginx http{} block. This is global
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3817 configuration.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3818 It stores global settings for a module
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3819 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3820
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3821 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3822 Server configuration.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3823 This configuraion applies to a single nginx server{}.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3824 It stores server-specific settings for a module
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3825 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3826
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3827 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3828 Location configuration.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3829 This configuraion applies to a single location{}, if{} or limit_except() block.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3830 This configuration stores settings specific to a location
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3831 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3832
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3833 </list>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3834
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3835 <para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3836 Configuration structures are created at nginx configuration stage by calling
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3837 functions, which allocate these structures, initialize them and merge.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3838 The following example shows how to create a simple module location
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3839 configuration.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3840 The configuration has one setting <literal>foo</literal> of unsiged integer
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3841 type.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3842 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3843
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3844 <programlisting>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3845 typedef struct {
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3846 ngx_uint_t foo;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3847 } ngx_http_foo_loc_conf_t;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3848
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3849
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3850 static ngx_http_module_t ngx_http_foo_module_ctx = {
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3851 NULL, /* preconfiguration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3852 NULL, /* postconfiguration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3853
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3854 NULL, /* create main configuration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3855 NULL, /* init main configuration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3856
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3857 NULL, /* create server configuration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3858 NULL, /* merge server configuration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3859
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3860 ngx_http_foo_create_loc_conf, /* create location configuration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3861 ngx_http_foo_merge_loc_conf /* merge location configuration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3862 };
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3863
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3864
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3865 static void *
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3866 ngx_http_foo_create_loc_conf(ngx_conf_t *cf)
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3867 {
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3868 ngx_http_foo_loc_conf_t *conf;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3869
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3870 conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_foo_loc_conf_t));
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3871 if (conf == NULL) {
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3872 return NULL;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3873 }
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3874
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3875 conf->foo = NGX_CONF_UNSET_UINT;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3876
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3877 return conf;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3878 }
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3879
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3880
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3881 static char *
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3882 ngx_http_foo_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3883 {
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3884 ngx_http_foo_loc_conf_t *prev = parent;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3885 ngx_http_foo_loc_conf_t *conf = child;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3886
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3887 ngx_conf_merge_uint_value(conf->foo, prev->foo, 1);
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3888 }
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3889 </programlisting>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3890
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3891 <para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3892 As seen in the example, <literal>ngx_http_foo_create_loc_conf()</literal>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3893 function creates a new configuration structure and
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3894 <literal>ngx_http_foo_merge_loc_conf()</literal> merges a configuration with
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3895 another configuration from a higher level.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3896 In fact, server and location configuration do not only exist at server and
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3897 location levels, but also created for all the levels above.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3898 Specifically, a server configuration is created at the main level as well and
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3899 location configurations are created for main, server and location levels.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3900 These configurations make it possible to specify server and location-specific
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3901 settings at any level of nginx configuration file.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3902 Eventually configurations are merged down.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3903 To indicate a missing setting and ignore it while merging, nginx provides a
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3904 number of macros like <literal>NGX_CONF_UNSET</literal> and
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3905 <literal>NGX_CONF_UNSET_UINT</literal>.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3906 Standard nginx merge macros like <literal>ngx_conf_merge_value()</literal> and
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3907 <literal>ngx_conf_merge_uint_value()</literal> provide a convenient way to
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3908 merge a setting and set the default value if none of configurations provided an
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3909 explicit value.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3910 For complete list of macros for different types see
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3911 <literal>src/core/ngx_conf_file.h</literal>.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3912 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3913
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3914 <para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3915 To access configuration of any HTTP module at configuration time, the following
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3916 macros are available.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3917 They receive <literal>ngx_conf_t</literal> reference as the first argument.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3918 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3919
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3920 <list type="bullet">
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3921
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3922 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3923 <literal>ngx_http_conf_get_module_main_conf(cf, module)</literal>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3924 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3925
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3926 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3927 <literal>ngx_http_conf_get_module_srv_conf(cf, module)</literal>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3928 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3930 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3931 <literal>ngx_http_conf_get_module_loc_conf(cf, module)</literal>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3932 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3933
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3934 </list>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3935
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3936 <para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3937 The following example gets a pointer to a location configuration of
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3938 standard nginx core module
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3939 <link doc="../http/ngx_http_core_module.xml">ngx_http_core_module</link>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3940 and changes
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3941 location content handler kept in the <literal>handler</literal> field of the
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3942 structure.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3943 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3944
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3945 <programlisting>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3946 static ngx_int_t ngx_http_foo_handler(ngx_http_request_t *r);
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3947
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3948
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3949 static ngx_command_t ngx_http_foo_commands[] = {
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3950
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3951 { ngx_string("foo"),
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3952 NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS,
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3953 ngx_http_foo,
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3954 0,
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3955 0,
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3956 NULL },
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3957
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3958 ngx_null_command
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3959 };
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3960
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3961
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3962 static char *
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3963 ngx_http_foo(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3964 {
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3965 ngx_http_core_loc_conf_t *clcf;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3966
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3967 clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3968 clcf->handler = ngx_http_bar_handler;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3969
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3970 return NGX_CONF_OK;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3971 }
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3972 </programlisting>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3973
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3974 <para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3975 In runtime the following macros are available to get configurations of HTTP
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3976 modules.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3977 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3978
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3979 <list type="bullet">
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3980
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3981 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3982 <literal>ngx_http_get_module_main_conf(r, module)</literal>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3983 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3984
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3985 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3986 <literal>ngx_http_get_module_srv_conf(r, module)</literal>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3987 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3988
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3989 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3990 <literal>ngx_http_get_module_loc_conf(r, module)</literal>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3991 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3992
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3993 </list>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3994
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3995 <para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3996 These macros receive a reference to an HTTP request
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3997 <literal>ngx_http_request_t</literal>.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3998 Main configuration of a request never changes.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
3999 Server configuration may change from a default one after choosing a virtual
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4000 server for a request.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4001 Request location configuration may change multiple times as a result of a
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4002 rewrite or internal redirect.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4003 The following example shows how to access HTTP configuration in runtime.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4004 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4005
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4006 <programlisting>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4007 static ngx_int_t
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4008 ngx_http_foo_handler(ngx_http_request_t *r)
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4009 {
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4010 ngx_http_foo_loc_conf_t *flcf;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4011
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4012 flcf = ngx_http_get_module_loc_conf(r, ngx_http_foo_module);
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4013
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4014 ...
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4015 }
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4016 </programlisting>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4017
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4018 </section>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4019
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4020
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4021 <section name="Phases" id="http_phases">
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4022
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4023 <para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4024 Each HTTP request passes through a list of HTTP phases.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4025 Each phase is specialized in a particular type of processing.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4026 Most phases allow installing handlers.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4027 The phase handlers are called successively once the request reaches the phase.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4028 Many standard nginx modules install their phase handlers as a way to get called
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4029 at a specific request processing stage.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4030 Following is the list of nginx HTTP phases.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4031 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4032
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4033 <list type="bullet">
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4034
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4035 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4036 <literal>NGX_HTTP_POST_READ_PHASE</literal> is the earliest phase.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4037 The <link doc="../http/ngx_http_realip_module.xml">ngx_http_realip_module</link>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4038 installs its handler at this phase.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4039 This allows to substitute client address before any other module is invoked
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4040 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4041
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4042 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4043 <literal>NGX_HTTP_SERVER_REWRITE_PHASE</literal> is used to run rewrite script,
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4044 defined at the server level, that is out of any location block.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4045 The
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4046 <link doc="../http/ngx_http_rewrite_module.xml">ngx_http_rewrite_module</link>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4047 installs its handler at this phase
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4048 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4049
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4050 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
4051 <literal>NGX_HTTP_FIND_CONFIG_PHASE</literal> — a special phase used to choose a
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4052 location based on request URI.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4053 This phase does not allow installing any handlers.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4054 It only performs the default action of choosing a location.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4055 Before this phase, the server default location is assigned to the request.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4056 Any module requesting a location configuration, will receive the default server
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4057 location configuration.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4058 After this phase a new location is assigned to the request
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4059 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4060
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4061 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
4062 <literal>NGX_HTTP_REWRITE_PHASE</literal> — same as
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4063 <literal>NGX_HTTP_SERVER_REWRITE_PHASE</literal>, but for a new location,
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4064 chosen at the prevous phase
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4065 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4066
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4067 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
4068 <literal>NGX_HTTP_POST_REWRITE_PHASE</literal> — a special phase, used to
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4069 redirect the request to a new location, if the URI was changed during rewrite.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4070 The redirect is done by going back to
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4071 <literal>NGX_HTTP_FIND_CONFIG_PHASE</literal>.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4072 No handlers are allowed at this phase
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4073 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4074
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4075 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
4076 <literal>NGX_HTTP_PREACCESS_PHASE</literal> — a common phase for different
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4077 types of handlers, not associated with access check.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4078 Standard nginx modules
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4079 <link doc="../http/ngx_http_limit_conn_module.xml">ngx_http_limit_conn_module
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4080 </link> and
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4081 <link doc="../http/ngx_http_limit_req_module.xml">
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4082 ngx_http_limit_req_module</link> register their handlers at this phase
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4083 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4084
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4085 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
4086 <literal>NGX_HTTP_ACCESS_PHASE</literal> — used to check access permissions
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4087 for the request.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4088 Standard nginx modules such as
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4089 <link doc="../http/ngx_http_access_module.xml">ngx_http_access_module</link> and
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4090 <link doc="../http/ngx_http_auth_basic_module.xml">ngx_http_auth_basic_module
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4091 </link> register their handlers at this phase.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4092 If configured so by the
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4093 <link doc="../http/ngx_http_core_module.xml" id="satisfy"/> directive, only one
1971
5fb870087b76 Fixed typo and removed trailing spaces.
Vladimir Homutov <vl@nginx.com>
parents: 1970
diff changeset
4094 of access phase handlers may allow access to the request in order to continue
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4095 processing
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4096 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4097
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4098 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
4099 <literal>NGX_HTTP_POST_ACCESS_PHASE</literal> — a special phase for the
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4100 <link doc="../http/ngx_http_core_module.xml" id="satisfy">satisfy any</link>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4101 case.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4102 If some access phase handlers denied the access and none of them allowed, the
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4103 request is finalized.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4104 No handlers are supported at this phase
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4105 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4106
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4107 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
4108 <literal>NGX_HTTP_TRY_FILES_PHASE</literal> — a special phase, for the
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4109 <link doc="../http/ngx_http_core_module.xml" id="try_files"/> feature.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4110 No handlers are allowed at this phase
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4111 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4112
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4113 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
4114 <literal>NGX_HTTP_CONTENT_PHASE</literal> — a phase, at which the response
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4115 is supposed to be generated.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4116 Multiple nginx standard modules register their handers at this phase, for
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4117 example
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4118 <link doc="../http/ngx_http_index_module.xml">ngx_http_index_module</link> or
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4119 <literal>ngx_http_static_module</literal>.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4120 All these handlers are called sequentially until one of them finally produces
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4121 the output.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4122 It's also possible to set content handlers on a per-location basis.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4123 If the
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4124 <link doc="../http/ngx_http_core_module.xml">ngx_http_core_module</link>'s
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4125 location configuration has <literal>handler</literal> set, this handler is
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4126 called as the content handler and content phase handlers are ignored
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4127 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4128
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4129 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4130 <literal>NGX_HTTP_LOG_PHASE</literal> is used to perform request logging.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4131 Currently, only the
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4132 <link doc="../http/ngx_http_log_module.xml">ngx_http_log_module</link>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4133 registers its handler
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4134 at this stage for access logging.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4135 Log phase handlers are called at the very end of request processing, right
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4136 before freeing the request
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4137 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4138
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4139 </list>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4140
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4141 <para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4142 Following is the example of a preaccess phase handler.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4143 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4144
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4145 <programlisting>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4146 static ngx_http_module_t ngx_http_foo_module_ctx = {
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4147 NULL, /* preconfiguration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4148 ngx_http_foo_init, /* postconfiguration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4149
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4150 NULL, /* create main configuration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4151 NULL, /* init main configuration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4152
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4153 NULL, /* create server configuration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4154 NULL, /* merge server configuration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4155
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4156 NULL, /* create location configuration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4157 NULL /* merge location configuration */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4158 };
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4159
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4160
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4161 static ngx_int_t
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4162 ngx_http_foo_handler(ngx_http_request_t *r)
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4163 {
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4164 ngx_str_t *ua;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4165
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4166 ua = r->headers_in->user_agent;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4167
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4168 if (ua == NULL) {
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4169 return NGX_DECLINED;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4170 }
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4171
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4172 /* reject requests with "User-Agent: foo" */
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4173 if (ua->value.len == 3 &amp;&amp; ngx_strncmp(ua->value.data, "foo", 3) == 0) {
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4174 return NGX_HTTP_FORBIDDEN;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4175 }
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4176
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4177 return NGX_DECLINED;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4178 }
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4179
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4180
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4181 static ngx_int_t
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4182 ngx_http_foo_init(ngx_conf_t *cf)
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4183 {
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4184 ngx_http_handler_pt *h;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4185 ngx_http_core_main_conf_t *cmcf;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4186
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4187 cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4188
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4189 h = ngx_array_push(&amp;cmcf->phases[NGX_HTTP_PREACCESS_PHASE].handlers);
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4190 if (h == NULL) {
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4191 return NGX_ERROR;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4192 }
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4193
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4194 *h = ngx_http_foo_handler;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4195
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4196 return NGX_OK;
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4197 }
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4198 </programlisting>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4199
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4200 <para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4201 Phase handlers are expected to return specific codes:
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4202 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4203
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4204 <list type="bullet">
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4205
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4206 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
4207 <literal>NGX_OK</literal> — proceed to the next phase
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
4208 </listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
4209
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
4210 <listitem>
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
4211 <literal>NGX_DECLINED</literal> — proceed to the next handler of the current
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4212 phase.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4213 If current handler is the last in current phase, move to the next phase
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4214 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4215
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4216 <listitem>
1935
be7490a66d1b Style: use long dash with non-breaking space where appropriate.
Vladimir Homutov <vl@nginx.com>
parents: 1932
diff changeset
4217 <literal>NGX_AGAIN, NGX_DONE</literal> — suspend phase handling until some
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4218 future event.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4219 This can be for example asynchronous I/O operation or just a delay.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4220 It is supposed, that phase handling will be resumed later by calling
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4221 <literal>ngx_http_core_run_phases()</literal>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4222 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4223
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4224 <listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4225 Any other value returned by the phase handler is treated as a request
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4226 finalization code, in particular, HTTP response code.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4227 The request is finalized with the code provided
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4228 </listitem>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4229
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4230 </list>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4231
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4232 <para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4233 Some phases treat return codes in a slightly different way.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4234 At content phase, any return code other that <literal>NGX_DECLINED</literal>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4235 is considered a finalization code.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4236 As for the location content handlers, any return from them is considered a
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4237 finalization code.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4238 At access phase, in
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4239 <link doc="../http/ngx_http_core_module.xml" id="satisfy">satisfy any</link>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4240 mode, returning a code other
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4241 than <literal>NGX_OK, NGX_DECLINED, NGX_AGAIN, NGX_DONE</literal> is considered
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4242 a denial.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4243 If none of future access handlers allow access or deny with a new
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4244 code, the denial code will become the finalization code.
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4245 </para>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4246
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4247 </section>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
4248
1939
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
4249
1959
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4250 <section name="Variables" id="http_variables">
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4251
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4252 <section name="Accessing existing variables" id="http_existing_variables">
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4253
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4254 <para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4255 Variables may be referenced using index (this is the most common method)
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4256 or names (see below in the section about creating variables).
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4257 Index is created at configuration stage, when a variable is added
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4258 to configuration.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4259 The variable index can be obtained using
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4260 <literal>ngx_http_get_variable_index()</literal>:
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4261 <programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4262 ngx_str_t name; /* ngx_string("foo") */
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4263 ngx_int_t index;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4264
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4265 index = ngx_http_get_variable_index(cf, &amp;name);
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4266 </programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4267 Here, the <literal>cf</literal> is a pointer to nginx configuration and the
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4268 <literal>name</literal> points to a string with the variable name.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4269 The function returns <literal>NGX_ERROR</literal> on error or valid index
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4270 otherwise, which is typically stored somewhere in a module configuration for
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4271 future use.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4272 </para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4273
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4274 <para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4275 All HTTP variables are evaluated in the context of HTTP request and results
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4276 are specific to and cached in HTTP request.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4277 All functions that evaluate variables return
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4278 <literal>ngx_http_variable_value_t</literal> type, representing
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4279 the variable value:
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4280 <programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4281 typedef ngx_variable_value_t ngx_http_variable_value_t;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4282
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4283 typedef struct {
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4284 unsigned len:28;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4285
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4286 unsigned valid:1;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4287 unsigned no_cacheable:1;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4288 unsigned not_found:1;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4289 unsigned escape:1;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4290
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4291 u_char *data;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4292 } ngx_variable_value_t;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4293 </programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4294 where:
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4295 <list type="bullet">
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4296
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4297 <listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4298 <literal>len</literal> — length of a value
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4299 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4300
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4301 <listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4302 <literal>data</literal> — value itself
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4303 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4304
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4305 <listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4306 <literal>valid</literal> — value is valid
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4307 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4308
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4309 <listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4310 <literal>not_found</literal> — variable was not found and thus
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4311 the <literal>data</literal> and <literal>len</literal> fields are irrelevant;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4312 this may happen, for example, with such variables as <var>$arg_foo</var>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4313 when a corresponding argument was not passed in a request
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4314 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4315
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4316 <listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4317 <literal>no_cacheable</literal> — do not cache result
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4318 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4319
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4320 <listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4321 <literal>escape</literal> — used internally by the logging module to mark
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4322 values that require escaping on output
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4323 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4324
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4325 </list>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4326 </para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4327
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4328 <para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4329 The <literal>ngx_http_get_flushed_variable()</literal>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4330 and <literal>ngx_http_get_indexed_variable()</literal> functions
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4331 are used to obtain the variable value.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4332 They have the same interface - accepting a HTTP request <literal>r</literal>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4333 as a context for evaluating the variable and an <literal>index</literal>,
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4334 identifying it.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4335 Example of typical usage:
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4336 <programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4337 ngx_http_variable_value_t *v;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4338
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4339 v = ngx_http_get_flushed_variable(r, index);
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4340
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4341 if (v == NULL || v->not_found) {
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4342 /* we failed to get value or there is no such variable, handle it */
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4343 return NGX_ERROR;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4344 }
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4345
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4346 /* some meaningful value is found */
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4347 </programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4348 The difference between functions is that the
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4349 <literal>ngx_http_get_indexed_variable()</literal> returns cached value
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4350 and <literal>ngx_http_get_flushed_variable()</literal> flushes cache for
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4351 non-cacheable variables.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4352 </para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4353
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4354 <para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4355 There are cases when it is required to deal with variables which names are
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4356 not known at configuration time and thus they cannot be accessed using indexes,
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4357 for example in modules like SSI or Perl.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4358 The <literal>ngx_http_get_variable(r, name, key)</literal> function may be
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4359 used in such cases.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4360 It searches for the <literal>variable</literal> with a given
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4361 <literal>name</literal> and its hash <literal>key</literal>.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4362 </para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4363
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4364 </section>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4365
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4366
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4367 <section name="Creating variables" id="http_creating_variables">
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4368
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4369 <para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4370 To create a variable <literal>ngx_http_add_variable()</literal> function
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4371 is used.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4372 It takes configuration (where variable is registered), variable name and
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4373 flags that control its behaviour:
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4374
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4375 <list type="bullet">
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4376 <listitem><literal>NGX_HTTP_VAR_CHANGEABLE</literal>  — allows redefining
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4377 the variable; If another module will define a variable with such name,
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4378 no conflict will happen.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4379 For example, this allows user to override variables using the
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4380 <link doc="../http/ngx_http_rewrite_module.xml" id="set"/> directive.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4381 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4382
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4383 <listitem><literal>NGX_HTTP_VAR_NOCACHEABLE</literal>  — disables caching,
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4384 is useful for such variables as <literal>$time_local</literal>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4385 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4386
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4387 <listitem><literal>NGX_HTTP_VAR_NOHASH</literal>  — indicates that
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4388 this variable is only accessible by index, not by name.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4389 This is a small optimization which may be used when it is known that the
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4390 variable is not needed in modules like SSI or Perl.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4391 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4392
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4393 <listitem><literal>NGX_HTTP_VAR_PREFIX</literal>  — the name of this
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4394 variable is a prefix.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4395 A handler must implement additional logic to obtain value of specific
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4396 variable.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4397 For example, all “<literal>arg_</literal>” variables are processed by the
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4398 same handler which performs lookup in request arguments and returns value
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4399 of specific argument.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4400 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4401
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4402 </list>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4403
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4404 The function returns NULL in case of error or a pointer to
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4405 <literal>ngx_http_variable_t</literal>:
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4406 <programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4407 struct ngx_http_variable_s {
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4408 ngx_str_t name;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4409 ngx_http_set_variable_pt set_handler;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4410 ngx_http_get_variable_pt get_handler;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4411 uintptr_t data;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4412 ngx_uint_t flags;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4413 ngx_uint_t index;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4414 };
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4415 </programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4416
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4417 The <literal>get</literal> and <literal>set</literal> handlers
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4418 are called to obtain or set the variable value,
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4419 <literal>data</literal> will be passed to variable handlers,
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4420 <literal>index</literal> will hold assigned variable index, used to reference
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4421 the variable.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4422 </para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4423
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4424 <para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4425 Usually, a null-terminated static array of such structures is created
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4426 by a module and processed at the preconfiguration stage to add variables
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4427 into configuration:
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4428 <programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4429 static ngx_http_variable_t ngx_http_foo_vars[] = {
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4430
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4431 { ngx_string("foo_v1"), NULL, ngx_http_foo_v1_variable, NULL, 0, 0 },
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4432
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4433 { ngx_null_string, NULL, NULL, 0, 0, 0 }
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4434 };
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4435
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4436 static ngx_int_t
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4437 ngx_http_foo_add_variables(ngx_conf_t *cf)
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4438 {
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4439 ngx_http_variable_t *var, *v;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4440
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4441 for (v = ngx_http_foo_vars; v->name.len; v++) {
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4442 var = ngx_http_add_variable(cf, &amp;v->name, v->flags);
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4443 if (var == NULL) {
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4444 return NGX_ERROR;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4445 }
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4446
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4447 var->get_handler = v->get_handler;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4448 var->data = v->data;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4449 }
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4450
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4451 return NGX_OK;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4452 }
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4453 </programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4454 This function is used to initialize the <literal>preconfiguration</literal>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4455 field of the HTTP module context and is called before parsing HTTP configuration,
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4456 so it could refer to these variables.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4457 </para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4458
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4459 <para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4460 The <literal>get</literal> handler is responsible for evaluating the variable
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4461 in a context of specific request, for example:
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4462 <programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4463 static ngx_int_t
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4464 ngx_http_variable_connection(ngx_http_request_t *r,
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4465 ngx_http_variable_value_t *v, uintptr_t data)
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4466 {
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4467 u_char *p;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4468
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4469 p = ngx_pnalloc(r->pool, NGX_ATOMIC_T_LEN);
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4470 if (p == NULL) {
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4471 return NGX_ERROR;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4472 }
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4473
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4474 v->len = ngx_sprintf(p, "%uA", r->connection->number) - p;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4475 v->valid = 1;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4476 v->no_cacheable = 0;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4477 v->not_found = 0;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4478 v->data = p;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4479
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4480 return NGX_OK;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4481 }
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4482 </programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4483 It returns <literal>NGX_ERROR</literal> in case of internal error
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4484 (for example, failed memory allocation) or <literal>NGX_OK</literal> otherwise.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4485 The status of variable evaluation may be understood by inspecting flags
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4486 of the <literal>ngx_http_variable_value_t</literal> (see description above).
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4487 </para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4488
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4489 <para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4490 The <literal>set</literal> handler allows setting the property
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4491 referred by the variable.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4492 For example, the <literal>$limit_rate</literal> variable set handler
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4493 modifies the request's <literal>limit_rate</literal> field:
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4494 <programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4495 ...
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4496 { ngx_string("limit_rate"), ngx_http_variable_request_set_size,
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4497 ngx_http_variable_request_get_size,
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4498 offsetof(ngx_http_request_t, limit_rate),
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4499 NGX_HTTP_VAR_CHANGEABLE|NGX_HTTP_VAR_NOCACHEABLE, 0 },
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4500 ...
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4501
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4502 static void
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4503 ngx_http_variable_request_set_size(ngx_http_request_t *r,
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4504 ngx_http_variable_value_t *v, uintptr_t data)
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4505 {
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4506 ssize_t s, *sp;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4507 ngx_str_t val;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4508
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4509 val.len = v->len;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4510 val.data = v->data;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4511
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4512 s = ngx_parse_size(&amp;val);
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4513
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4514 if (s == NGX_ERROR) {
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4515 ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4516 "invalid size \"%V\"", &amp;val);
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4517 return;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4518 }
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4519
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4520 sp = (ssize_t *) ((char *) r + data);
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4521
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4522 *sp = s;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4523
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4524 return;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4525 }
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4526 </programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4527
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4528 </para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4529
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4530 </section>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4531
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4532 </section>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4533
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4534
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4535 <section name="Complex values" id="http_complex_values">
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4536
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4537 <para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4538 A complex value, despite its name, provides an easy way to evaluate
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4539 expressions that may contain text, variables, and their combination.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4540 </para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4541
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4542 <para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4543 The complex value description in
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4544 <literal>ngx_http_compile_complex_value</literal> is compiled at the
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4545 configuration stage into <literal>ngx_http_complex_value_t</literal>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4546 which is used at runtime to obtain evaluated expression results.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4547
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4548 <programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4549 ngx_str_t *value;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4550 ngx_http_complex_value_t cv;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4551 ngx_http_compile_complex_value_t ccv;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4552
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4553 value = cf->args->elts; /* directive arguments */
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4554
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4555 ngx_memzero(&amp;ccv, sizeof(ngx_http_compile_complex_value_t));
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4556
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4557 ccv.cf = cf;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4558 ccv.value = &amp;value[1];
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4559 ccv.complex_value = &amp;cv;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4560 ccv.zero = 1;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4561 ccv.conf_prefix = 1;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4562
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4563 if (ngx_http_compile_complex_value(&amp;ccv) != NGX_OK) {
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4564 return NGX_CONF_ERROR;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4565 }
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4566 </programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4567
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4568 Here, <literal>ccv</literal> holds all parameters that are required to
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4569 initialize the complex value <literal>cv</literal>:
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4570
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4571 <list type="bullet">
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4572
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4573 <listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4574 <literal>cf</literal> — configuration pointer
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4575 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4576
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4577 <listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4578 <literal>value</literal> — string for parsing (input)
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4579 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4580
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4581 <listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4582 <literal>complex_value</literal> — compiled value (output)
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4583 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4584
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4585 <listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4586 <literal>zero</literal> — flag that enables zero-terminating value
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4587 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4588
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4589 <listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4590 <literal>conf_prefix</literal> — prefixes result with configuration prefix
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4591 (the directory where nginx is currently looking for configuration)
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4592 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4593
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4594 <listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4595 <literal>root_prefix</literal> — prefixes result with root prefix
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4596 (this is the normal nginx installation prefix)
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4597 </listitem>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4598
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4599 </list>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4600 The <literal>zero</literal> flag is usable when results are to be passed to
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4601 libraries that require zero-terminated strings, and prefixes are handy when
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4602 dealing with filenames.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4603 </para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4604
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4605 <para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4606 Upon successful compilation, <literal>cv.lengths</literal> may
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4607 be inspected to get information about the presence of variables
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4608 in the expression.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4609 The NULL value means that the expression contained static text only,
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4610 and there is no need in storing it as a complex value,
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4611 so a simple string can be used.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4612 </para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4613
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4614 <para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4615 The <literal>ngx_http_set_complex_value_slot()</literal> is a convenient
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4616 function used to initialize complex value completely right in the directive
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4617 declaration.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4618 </para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4619
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4620 <para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4621 At runtime, a complex value may be calculated using the
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4622 <literal>ngx_http_complex_value()</literal> function:
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4623 <programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4624 ngx_str_t res;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4625
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4626 if (ngx_http_complex_value(r, &amp;cv, &amp;res) != NGX_OK) {
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4627 return NGX_ERROR;
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4628 }
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4629 </programlisting>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4630 Given the request <literal>r</literal> and previously compiled
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4631 value <literal>cv</literal> the function will evaluate
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4632 expression and put result into <literal>res</literal>.
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4633 </para>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4634
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4635 </section>
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4636
d0aebb2337ec Added the "Variables" section to the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1958
diff changeset
4637
1967
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4638 <section name="Request redirection" id="http_request_redirection">
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4639
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4640 <para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4641 An HTTP request is always connected to a location via the
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4642 <literal>loc_conf</literal> field of the <literal>ngx_http_request_t</literal>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4643 structure.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4644 This means that at any point the location configuration of any module can be
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4645 retrieved from the request by calling
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4646 <literal>ngx_http_get_module_loc_conf(r, module)</literal>.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4647 Request location may be changed several times throughout its lifetime.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4648 Initially, a default server location of the default server is assigned to a
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4649 request.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4650 Once a request switches to a different server (chosen by the HTTP
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4651 <header>Host</header> header or SSL SNI extension), the request switches to the
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4652 default location of that server as well.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4653 The next change of the location takes place at the
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4654 <literal>NGX_HTTP_FIND_CONFIG_PHASE</literal> request phase.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4655 At this phase a location is chosen by request URI among all non-named locations
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4656 configured for the server.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4657 The
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4658 <link doc="../http/ngx_http_rewrite_module.xml">ngx_http_rewrite_module</link>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4659 may change the request URI at the
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4660 <literal>NGX_HTTP_REWRITE_PHASE</literal> request phase as a result of
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4661 <link doc="../http/ngx_http_rewrite_module.xml" id="rewrite">rewrite</link> and
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4662 return to the <literal>NGX_HTTP_FIND_CONFIG_PHASE</literal> phase for choosing a
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4663 new location based on the new URI.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4664 </para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4665
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4666 <para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4667 It is also possible to redirect a request to a new location at any point by
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4668 calling one of the functions
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4669 <literal>ngx_http_internal_redirect(r, uri, args)</literal> or
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4670 <literal>ngx_http_named_location(r, name)</literal>.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4671 </para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4672
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4673 <para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4674 The function <literal>ngx_http_internal_redirect(r, uri, args)</literal> changes
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4675 the request URI and returns the request to the
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4676 <literal>NGX_HTTP_SERVER_REWRITE_PHASE</literal> phase.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4677 The request proceeds with a server default location.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4678 Later at <literal>NGX_HTTP_FIND_CONFIG_PHASE</literal> a new location is chosen
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4679 based on the new request URI.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4680 </para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4681
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4682 <para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4683 The following example performs an internal redirect with the new request
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4684 arguments.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4685 </para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4686
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4687 <programlisting>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4688 ngx_int_t
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4689 ngx_http_foo_redirect(ngx_http_request_t *r)
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4690 {
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4691 ngx_str_t uri, args;
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4692
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4693 ngx_str_set(&amp;uri, "/foo");
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4694 ngx_str_set(&amp;args, "bar=1");
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4695
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4696 return ngx_http_internal_redirect(r, &amp;uri, &amp;args);
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4697 }
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4698 </programlisting>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4699
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4700 <para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4701 The function <literal>ngx_http_named_location(r, name)</literal> redirects
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4702 a request to a named location. The name of the location is passed as the
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4703 argument. The location is looked up among all named locations of the current
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4704 server, after which the requests switches to the
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4705 <literal>NGX_HTTP_REWRITE_PHASE</literal> phase.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4706 </para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4707
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4708 <para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4709 The following example performs a redirect to a named location @foo.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4710 </para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4711
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4712 <programlisting>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4713 ngx_int_t
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4714 ngx_http_foo_named_redirect(ngx_http_request_t *r)
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4715 {
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4716 ngx_str_t name;
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4717
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4718 ngx_str_set(&amp;name, "foo");
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4719
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4720 return ngx_http_named_location(r, &amp;name);
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4721 }
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4722 </programlisting>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4723
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4724 <para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4725 Both functions <literal>ngx_http_internal_redirect(r, uri, args)</literal>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4726 and <literal>ngx_http_named_location(r, name)</literal> may be called when
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4727 a request already has some contexts saved in its <literal>ctx</literal> field
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4728 by nginx modules. These contexts could become inconsistent with the new
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4729 location configuration. To prevent inconsistency, all request contexts are
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4730 erased by both redirect functions.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4731 </para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4732
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4733 <para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4734 Redirected and rewritten requests become internal and may access the
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4735 <link doc="../http/ngx_http_core_module.xml" id="internal">internal</link>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4736 locations. Internal requests have the <literal>internal</literal> flag set.
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4737 </para>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4738
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4739 </section>
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4740
ef27e3ef0c46 The HTTP request redirection section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1960
diff changeset
4741
1968
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4742 <section name="Subrequests" id="http_subrequests">
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4743
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4744 <para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4745 Subrequests are primarily used to include output of one request into another,
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4746 possibly mixed with other data.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4747 A subrequest looks like a normal request, but shares some data with its parent.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4748 Particularly, all fields related to client input are shared since a subrequest
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4749 does not receive any other input from client.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4750 The request field <literal>parent</literal> for a subrequest keeps a link to its
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4751 parent request and is NULL for the main request.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4752 The field <literal>main</literal> keeps a link to the main request in a group of
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4753 requests.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4754 </para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4755
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4756 <para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4757 A subrequest starts with <literal>NGX_HTTP_SERVER_REWRITE_PHASE</literal> phase.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4758 It passes through the same phases as a normal request and is assigned a location
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4759 based on its own URI.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4760 </para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4761
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4762 <para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4763 Subrequest output header is always ignored.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4764 Subrequest output body is placed by the
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4765 <literal>ngx_http_postpone_filter</literal> into the right position in relation
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4766 to other data produced by the parent request.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4767 </para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4768
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4769 <para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4770 Subrequests are related to the concept of active requests.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4771 A request <literal>r</literal> is considered active if
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4772 <literal>c->data == r</literal>, where <literal>c</literal> is the client
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4773 connection object.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4774 At any point, only the active request in a request group is allowed to output
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4775 its buffers to the client.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4776 A non-active request can still send its data to the filter chain, but they
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4777 will not pass beyond the <literal>ngx_http_postpone_filter</literal> and will
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4778 remain buffered by that filter until the request becomes active.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4779 Here are some rules of request activation:
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4780 </para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4781
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4782 <list type="bullet">
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4783
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4784 <listitem>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4785 Initially, the main request is active
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4786 </listitem>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4787
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4788 <listitem>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4789 The first subrequest of an active request becomes active right after creation
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4790 </listitem>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4791
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4792 <listitem>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4793 The <literal>ngx_http_postpone_filter</literal> activates the next request
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4794 in active request's subrequest list, once all data prior to that request are
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4795 sent
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4796 </listitem>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4797
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4798 <listitem>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4799 When a request is finalized, its parent is activated
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4800 </listitem>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4801
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4802 </list>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4803
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4804 <para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4805 A subrequest is created by calling the function
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4806 <literal>ngx_http_subrequest(r, uri, args, psr, ps, flags)</literal>, where
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4807 <literal>r</literal> is the parent request, <literal>uri</literal> and
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4808 <literal>args</literal> are URI and arguments of the
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4809 subrequest, <literal>psr</literal> is the output parameter, receiving the
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4810 newly created subrequest reference, <literal>ps</literal> is a callback object
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4811 for notifying the parent request that the subrequest is being finalized,
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4812 <literal>flags</literal> is subrequest creation flags bitmask.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4813 The following flags are available:
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4814 </para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4815
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4816 <list type="bullet">
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4817
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4818 <listitem>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4819 <literal>NGX_HTTP_SUBREQUEST_IN_MEMORY</literal> - subrequest output should not
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4820 be sent to the client, but rather stored in memory.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4821 This only works for proxying subrequests.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4822 After subrequest finalization its output is available in
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4823 <literal>r->upstream->buffer</literal> buffer of type
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4824 <literal>ngx_buf_t</literal>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4825 </listitem>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4826
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4827 <listitem>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4828 <literal>NGX_HTTP_SUBREQUEST_WAITED</literal> - the subrequest
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4829 <literal>done</literal> flag is set even if it is finalized being non-active.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4830 This subrequest flag is used by the SSI filter
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4831 </listitem>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4832
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4833 <listitem>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4834 <literal>NGX_HTTP_SUBREQUEST_CLONE</literal> - the subrequest is created as a
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4835 clone of its parent.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4836 It is started at the same location and proceeds from the same phase as the
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4837 parent request
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4838 </listitem>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4839
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4840 </list>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4841
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4842 <para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4843 The following example creates a subrequest with the URI of "/foo".
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4844 </para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4845
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4846 <programlisting>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4847 ngx_int_t rc;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4848 ngx_str_t uri;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4849 ngx_http_request_t *sr;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4850
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4851 ...
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4852
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4853 ngx_str_set(&amp;uri, "/foo");
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4854
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4855 rc = ngx_http_subrequest(r, &amp;uri, NULL, &amp;sr, NULL, 0);
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4856 if (rc == NGX_ERROR) {
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4857 /* error */
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4858 }
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4859 </programlisting>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4860
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4861 <para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4862 This example clones the current request and sets a finalization callback for the
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4863 subrequest.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4864 </para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4865
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4866 <programlisting>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4867 ngx_int_t
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4868 ngx_http_foo_clone(ngx_http_request_t *r)
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4869 {
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4870 ngx_http_request_t *sr;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4871 ngx_http_post_subrequest_t *ps;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4872
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4873 ps = ngx_palloc(r->pool, sizeof(ngx_http_post_subrequest_t));
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4874 if (ps == NULL) {
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4875 return NGX_ERROR;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4876 }
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4877
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4878 ps->handler = ngx_http_foo_subrequest_done;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4879 ps->data = "foo";
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4880
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4881 return ngx_http_subrequest(r, &amp;r->uri, &amp;r->args, &amp;sr, ps,
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4882 NGX_HTTP_SUBREQUEST_CLONE);
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4883 }
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4884
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4885
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4886 ngx_int_t
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4887 ngx_http_foo_subrequest_done(ngx_http_request_t *r, void *data, ngx_int_t rc)
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4888 {
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4889 char *msg = (char *) data;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4890
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4891 ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4892 "done subrequest r:%p msg:%s rc:%i", r, msg, rc);
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4893
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4894 return rc;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4895 }
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4896 </programlisting>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4897
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4898 <para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4899 Subrequests are normally created in a body filter.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4900 In this case subrequest output can be treated as any other explicit request
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4901 output.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4902 This means that eventually the output of a subrequest is sent to the client
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4903 after all explicit buffers passed prior to subrequest creation and before any
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4904 buffers passed later.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4905 This ordering is preserved even for large hierarchies of subrequests.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4906 The following example inserts a subrequest output after all request data
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4907 buffers, but before the final buffer with the <literal>last_buf</literal> flag.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4908 </para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4909
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4910 <programlisting>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4911 ngx_int_t
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4912 ngx_http_foo_body_filter(ngx_http_request_t *r, ngx_chain_t *in)
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4913 {
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4914 ngx_int_t rc;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4915 ngx_buf_t *b;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4916 ngx_uint_t last;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4917 ngx_chain_t *cl, out;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4918 ngx_http_request_t *sr;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4919 ngx_http_foo_filter_ctx_t *ctx;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4920
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4921 ctx = ngx_http_get_module_ctx(r, ngx_http_foo_filter_module);
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4922 if (ctx == NULL) {
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4923 return ngx_http_next_body_filter(r, in);
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4924 }
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4925
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4926 last = 0;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4927
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4928 for (cl = in; cl; cl = cl->next) {
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4929 if (cl->buf->last_buf) {
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4930 cl->buf->last_buf = 0;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4931 cl->buf->last_in_chain = 1;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4932 cl->buf->sync = 1;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4933 last = 1;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4934 }
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4935 }
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4936
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4937 /* Output explicit output buffers */
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4938
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4939 rc = ngx_http_next_body_filter(r, in);
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4940
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4941 if (rc == NGX_ERROR || !last) {
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4942 return rc;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4943 }
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4944
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4945 /*
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4946 * Create the subrequest. The output of the subrequest
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4947 * will automatically be sent after all preceding buffers,
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4948 * but before the last_buf buffer passed later in this function.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4949 */
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4950
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4951 if (ngx_http_subrequest(r, ctx->uri, NULL, &amp;sr, NULL, 0) != NGX_OK) {
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4952 return NGX_ERROR;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4953 }
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4954
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4955 ngx_http_set_ctx(r, NULL, ngx_http_foo_filter_module);
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4956
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4957
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4958 /* Output the final buffer with the last_buf flag */
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4959
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4960 b = ngx_calloc_buf(r->pool);
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4961 if (b == NULL) {
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4962 return NGX_ERROR;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4963 }
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4964
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4965 b->last_buf = 1;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4966
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4967 out.buf = b;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4968 out.next = NULL;
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4969
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4970 return ngx_http_output_filter(r, &amp;out);
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4971 }
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4972 </programlisting>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4973
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4974 <para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4975 A subrequest may also be created for other purposes than data output.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4976 For example, the <link doc="../http/ngx_http_auth_request_module.xml">
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4977 ngx_http_auth_request_module</link>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4978 creates a subrequest at <literal>NGX_HTTP_ACCESS_PHASE</literal> phase.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4979 To disable any output at this point, the subrequest
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4980 <literal>header_only</literal> flag is set.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4981 This prevents subrequest body from being sent to the client.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4982 Its header is ignored anyway.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4983 The result of the subrequest can be analyzed in the callback handler.
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4984 </para>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4985
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4986 </section>
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4987
69908bd68481 The HTTP subrequests section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1967
diff changeset
4988
1969
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
4989 <section name="Request finalization" id="http_request_finalization">
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
4990
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
4991 <para>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
4992 An HTTP request is finalized by calling the function
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
4993 <literal>ngx_http_finalize_request(r, rc)</literal>.
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
4994 It is usually finalized by the content handler after sending all output buffers
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
4995 to the filter chain.
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
4996 At this point the output may not be completely sent to the client, but remain
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
4997 buffered somewhere along the filter chain.
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
4998 If it is, the <literal>ngx_http_finalize_request(r, rc)</literal> function will
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
4999 automatically install a special handler <literal>ngx_http_writer(r)</literal>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5000 to finish sending the output.
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5001 A request is also finalized in case of an error or if a standard HTTP response
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5002 code needs to be returned to the client.
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5003 </para>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5004
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5005 <para>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5006 The function <literal>ngx_http_finalize_request(r, rc)</literal> expects the
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5007 following <literal>rc</literal> values:
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5008 </para>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5009
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5010 <list type="bullet">
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5011
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5012 <listitem>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5013 <literal>NGX_DONE</literal> - fast finalization.
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5014 Decrement request <literal>count</literal> and destroy the request if it
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5015 reaches zero.
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5016 The client connection may still be used for more requests after that
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5017 </listitem>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5018
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5019 <listitem>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5020 <literal>NGX_ERROR</literal>, <literal>NGX_HTTP_REQUEST_TIME_OUT</literal>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5021 (408), <literal>NGX_HTTP_CLIENT_CLOSED_REQUEST</literal> (499) - error
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5022 finalization.
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5023 Terminate the request as soon as possible and close the client connection.
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5024 </listitem>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5025
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5026 <listitem>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5027 <literal>NGX_HTTP_CREATED</literal> (201),
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5028 <literal>NGX_HTTP_NO_CONTENT</literal> (204), codes greater than or equal to
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5029 <literal>NGX_HTTP_SPECIAL_RESPONSE</literal> (300) - special response
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5030 finalization.
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5031 For these values nginx either sends a default code response page to the client
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5032 or performs the internal redirect to an
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5033 <link doc="../http/ngx_http_core_module.xml" id="error_page"/> location if it's
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5034 configured for the code
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5035 </listitem>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5036
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5037 <listitem>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5038 Other codes are considered success finalization codes and may activate the
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5039 request writer to finish sending the response body.
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5040 Once body is completely sent, request <literal>count</literal> is decremented.
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5041 If it reaches zero, the request is destroyed, but the client connection may
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5042 still be used for other requests.
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5043 If <literal>count</literal> is positive, there are unfinished activities
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5044 within the request, which will be finalized at a later point.
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5045 </listitem>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5046
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5047 </list>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5048
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5049 </section>
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5050
275c928ab386 The HTTP request finalization section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1968
diff changeset
5051
1970
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5052 <section name="Request body" id="http_request_body">
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5053
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5054 <para>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5055 For dealing with client request body, nginx provides the following functions:
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5056 <literal>ngx_http_read_client_request_body(r, post_handler)</literal> and
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5057 <literal>ngx_http_discard_request_body(r)</literal>.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5058 The first function reads the request body and makes it available via the
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5059 <literal>request_body</literal> request field.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5060 The second function instructs nginx to discard (read and ignore) the request
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5061 body.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5062 One of these functions must be called for every request.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5063 Normally, it is done in the content handler.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5064 </para>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5065
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5066 <para>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5067 Reading or discarding client request body from a subrequest is not allowed.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5068 It should always be done in the main request.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5069 When a subrequest is created, it inherits the parent
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5070 <literal>request_body</literal> object which can be used by the subrequest if
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5071 the main request has previously read the request body.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5072 </para>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5073
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5074 <para>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5075 The function
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5076 <literal>ngx_http_read_client_request_body(r, post_handler)</literal> starts
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5077 the process of reading the request body.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5078 When the body is completely read, the <literal>post_handler</literal> callback
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5079 is called to continue processing the request.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5080 If request body is missing or already read, the callback is called immediately.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5081 The function
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5082 <literal>ngx_http_read_client_request_body(r, post_handler)</literal>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5083 allocates the <literal>request_body</literal> request field of type
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5084 <literal>ngx_http_request_body_t</literal>.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5085 The field <literal>bufs</literal> of this object keeps the result as a buffer
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5086 chain.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5087 The body can be saved in memory buffers or file buffers, if
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5088 <link doc="../http/ngx_http_core_module.xml" id="client_body_buffer_size"/>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5089 is not enough to fit the entire body in memory.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5090 </para>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5091
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5092 <para>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5093 The following example reads client request body and returns its size.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5094 </para>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5095
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5096 <programlisting>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5097 ngx_int_t
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5098 ngx_http_foo_content_handler(ngx_http_request_t *r)
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5099 {
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5100 ngx_int_t rc;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5101
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5102 rc = ngx_http_read_client_request_body(r, ngx_http_foo_init);
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5103
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5104 if (rc >= NGX_HTTP_SPECIAL_RESPONSE) {
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5105 /* error */
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5106 return rc;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5107 }
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5108
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5109 return NGX_DONE;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5110 }
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5111
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5112
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5113 void
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5114 ngx_http_foo_init(ngx_http_request_t *r)
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5115 {
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5116 off_t len;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5117 ngx_buf_t *b;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5118 ngx_int_t rc;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5119 ngx_chain_t *in, out;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5120
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5121 if (r->request_body == NULL) {
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5122 ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5123 return;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5124 }
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5125
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5126 len = 0;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5127
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5128 for (in = r->request_body->bufs; in; in = in->next) {
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5129 len += ngx_buf_size(in->buf);
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5130 }
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5131
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5132 b = ngx_create_temp_buf(r->pool, NGX_OFF_T_LEN);
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5133 if (b == NULL) {
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5134 ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5135 return;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5136 }
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5137
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5138 b->last = ngx_sprintf(b->pos, "%O", len);
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5139 b->last_buf = (r == r->main) ? 1: 0;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5140 b->last_in_chain = 1;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5141
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5142 r->headers_out.status = NGX_HTTP_OK;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5143 r->headers_out.content_length_n = b->last - b->pos;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5144
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5145 rc = ngx_http_send_header(r);
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5146
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5147 if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5148 ngx_http_finalize_request(r, rc);
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5149 return;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5150 }
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5151
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5152 out.buf = b;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5153 out.next = NULL;
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5154
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5155 rc = ngx_http_output_filter(r, &amp;out);
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5156
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5157 ngx_http_finalize_request(r, rc);
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5158 }
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5159 </programlisting>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5160
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5161 <para>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5162 The following fields of the request affect the way request body is read:
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5163 </para>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5164
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5165 <list type="bullet">
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5166
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5167 <listitem>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5168 <literal>request_body_in_single_buf</literal> - read body to a single memory
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5169 buffer
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5170 </listitem>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5171
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5172 <listitem>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5173 <literal>request_body_in_file_only</literal> - always read body to a file,
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5174 even if fits the memory buffer
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5175 </listitem>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5176
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5177 <listitem>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5178 <literal>request_body_in_persistent_file</literal> - do not unlink the file
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5179 right after creation.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5180 Such a file can be moved to another directory
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5181 </listitem>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5182
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5183 <listitem>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5184 <literal>request_body_in_clean_file</literal> - unlink the file the when the
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5185 request is finalized.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5186 This can be useful when a file was supposed to be moved to another directory
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5187 but eventually was not moved for some reason
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5188 </listitem>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5189
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5190 <listitem>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5191 <literal>request_body_file_group_access</literal> - enable file group access.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5192 By default a file is created with 0600 access mask.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5193 When the flag is set, 0660 access mask is used
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5194 </listitem>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5195
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5196 <listitem>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5197 <literal>request_body_file_log_level</literal> - log file errors with this
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5198 log level
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5199 </listitem>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5200
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5201 <listitem>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5202 <literal>request_body_no_buffering</literal> - read request body without
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5203 buffering
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5204 </listitem>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5205
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5206 </list>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5207
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5208 <para>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5209 When the <literal>request_body_no_buffering</literal> flag is set, the
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5210 unbuffered mode of reading the request body is enabled.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5211 In this mode, after calling
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5212 <literal>ngx_http_read_client_request_body()</literal>, the
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5213 <literal>bufs</literal> chain may keep only a part of the body.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5214 To read the next part, the
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5215 <literal>ngx_http_read_unbuffered_request_body(r)</literal> function should be
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5216 called.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5217 The return value of <literal>NGX_AGAIN</literal> and the request flag
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5218 <literal>reading_body</literal> indicate that more data is available.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5219 If <literal>bufs</literal> is NULL after calling this function, there is
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5220 nothing to read at the moment.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5221 The request callback <literal>read_event_handler</literal> will be called when
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5222 the next part of request body is available.
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5223 </para>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5224
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5225 </section>
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5226
a1d29eda04b6 The HTTP request body section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1969
diff changeset
5227
1960
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5228 <section name="Response" id="http_response">
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5229
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5230 <para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5231 An HTTP response in nginx is produced by sending the response header followed by
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5232 the optional response body.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5233 Both header and body are passed through a chain of filters and eventually get
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5234 written to the client socket.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5235 An nginx module can install its handler into the header or body filter chain
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5236 and process the output coming from the previous handler.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5237 </para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5238
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5239
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5240 <section name="Response header" id="http_response_header">
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5241
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5242 <para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5243 Output header is sent by the function
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5244 <literal>ngx_http_send_header(r)</literal>.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5245 Prior to calling this function, <literal>r->headers_out</literal> should contain
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5246 all the data required to produce the HTTP response header.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5247 It's always required to set the <literal>status</literal> field of
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5248 <literal>r->headers_out</literal>.
1971
5fb870087b76 Fixed typo and removed trailing spaces.
Vladimir Homutov <vl@nginx.com>
parents: 1970
diff changeset
5249 If the response status suggests that a response body follows the header,
1960
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5250 <literal>content_length_n</literal> can be set as well.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5251 The default value for this field is -1, which means that the body size is
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5252 unknown.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5253 In this case, chunked transfer encoding is used.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5254 To output an arbitrary header, <literal>headers</literal> list should be
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5255 appended.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5256 </para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5257
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5258 <programlisting>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5259 static ngx_int_t
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5260 ngx_http_foo_content_handler(ngx_http_request_t *r)
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5261 {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5262 ngx_int_t rc;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5263 ngx_table_elt_t *h;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5264
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5265 /* send header */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5266
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5267 r->headers_out.status = NGX_HTTP_OK;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5268 r->headers_out.content_length_n = 3;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5269
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5270 /* X-Foo: foo */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5271
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5272 h = ngx_list_push(&amp;r->headers_out.headers);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5273 if (h == NULL) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5274 return NGX_ERROR;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5275 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5276
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5277 h->hash = 1;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5278 ngx_str_set(&amp;h->key, "X-Foo");
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5279 ngx_str_set(&amp;h->value, "foo");
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5280
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5281 rc = ngx_http_send_header(r);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5282
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5283 if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5284 return rc;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5285 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5286
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5287 /* send body */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5288
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5289 ...
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5290 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5291 </programlisting>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5292
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5293 </section>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5294
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5295
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5296 <section name="Header filters" id="http_header_filters">
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5297
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5298 <para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5299 The <literal>ngx_http_send_header(r)</literal> function invokes the header
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5300 filter chain by calling the top header filter handler
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5301 <literal>ngx_http_top_header_filter</literal>.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5302 It's assumed that every header handler calls the next handler in chain until
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5303 the final handler <literal>ngx_http_header_filter(r)</literal> is called.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5304 The final header handler constructs the HTTP response based on
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5305 <literal>r->headers_out</literal> and passes it to the
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5306 <literal>ngx_http_writer_filter</literal> for output.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5307 </para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5308
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5309 <para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5310 To add a handler to the header filter chain, one should store its address in
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5311 <literal>ngx_http_top_header_filter</literal> global variable at configuration
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5312 time.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5313 The previous handler address is normally stored in a module's static variable
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5314 and is called by the newly added handler before exiting.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5315 </para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5316
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5317 <para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5318 The following is an example header filter module, adding the HTTP header
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5319 "X-Foo: foo" to every output with the status 200.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5320 </para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5321
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5322 <programlisting>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5323 #include &lt;ngx_config.h&gt;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5324 #include &lt;ngx_core.h&gt;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5325 #include &lt;ngx_http.h&gt;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5326
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5327
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5328 static ngx_int_t ngx_http_foo_header_filter(ngx_http_request_t *r);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5329 static ngx_int_t ngx_http_foo_header_filter_init(ngx_conf_t *cf);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5330
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5331
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5332 static ngx_http_module_t ngx_http_foo_header_filter_module_ctx = {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5333 NULL, /* preconfiguration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5334 ngx_http_foo_header_filter_init, /* postconfiguration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5335
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5336 NULL, /* create main configuration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5337 NULL, /* init main configuration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5338
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5339 NULL, /* create server configuration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5340 NULL, /* merge server configuration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5341
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5342 NULL, /* create location configuration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5343 NULL /* merge location configuration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5344 };
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5345
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5346
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5347 ngx_module_t ngx_http_foo_header_filter_module = {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5348 NGX_MODULE_V1,
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5349 &amp;ngx_http_foo_header_filter_module_ctx, /* module context */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5350 NULL, /* module directives */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5351 NGX_HTTP_MODULE, /* module type */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5352 NULL, /* init master */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5353 NULL, /* init module */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5354 NULL, /* init process */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5355 NULL, /* init thread */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5356 NULL, /* exit thread */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5357 NULL, /* exit process */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5358 NULL, /* exit master */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5359 NGX_MODULE_V1_PADDING
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5360 };
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5361
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5362
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5363 static ngx_http_output_header_filter_pt ngx_http_next_header_filter;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5364
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5365
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5366 static ngx_int_t
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5367 ngx_http_foo_header_filter(ngx_http_request_t *r)
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5368 {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5369 ngx_table_elt_t *h;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5370
1971
5fb870087b76 Fixed typo and removed trailing spaces.
Vladimir Homutov <vl@nginx.com>
parents: 1970
diff changeset
5371 /*
1960
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5372 * The filter handler adds "X-Foo: foo" header
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5373 * to every HTTP 200 response
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5374 */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5375
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5376 if (r->headers_out.status != NGX_HTTP_OK) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5377 return ngx_http_next_header_filter(r);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5378 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5379
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5380 h = ngx_list_push(&amp;r->headers_out.headers);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5381 if (h == NULL) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5382 return NGX_ERROR;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5383 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5384
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5385 h->hash = 1;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5386 ngx_str_set(&amp;h->key, "X-Foo");
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5387 ngx_str_set(&amp;h->value, "foo");
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5388
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5389 return ngx_http_next_header_filter(r);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5390 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5391
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5392
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5393 static ngx_int_t
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5394 ngx_http_foo_header_filter_init(ngx_conf_t *cf)
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5395 {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5396 ngx_http_next_header_filter = ngx_http_top_header_filter;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5397 ngx_http_top_header_filter = ngx_http_foo_header_filter;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5398
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5399 return NGX_OK;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5400 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5401 </programlisting>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5402
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5403 </section>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5404
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5405 </section>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5406
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5407
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5408 <section name="Response body" id="http_response_body">
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5409
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5410 <para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5411 Response body is sent by calling the function
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5412 <literal>ngx_http_output_filter(r, cl)</literal>.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5413 The function can be called multiple times.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5414 Each time it sends a part of the response body passed as a buffer chain.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5415 The last body buffer should have the <literal>last_buf</literal> flag set.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5416 </para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5417
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5418 <para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5419 The following example produces a complete HTTP output with "foo" as its body.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5420 In order for the example to work not only as a main request but as a subrequest
1980
5718cf42be55 Fixed a typo.
Vladimir Homutov <vl@nginx.com>
parents: 1979
diff changeset
5421 as well, the <literal>last_in_chain</literal> flag is set in the last buffer
1960
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5422 of the output.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5423 The <literal>last_buf</literal> flag is set only for the main request since
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5424 a subrequest's last buffers does not end the entire output.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5425 </para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5426
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5427 <programlisting>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5428 static ngx_int_t
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5429 ngx_http_bar_content_handler(ngx_http_request_t *r)
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5430 {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5431 ngx_int_t rc;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5432 ngx_buf_t *b;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5433 ngx_chain_t out;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5434
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5435 /* send header */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5436
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5437 r->headers_out.status = NGX_HTTP_OK;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5438 r->headers_out.content_length_n = 3;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5439
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5440 rc = ngx_http_send_header(r);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5441
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5442 if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5443 return rc;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5444 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5445
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5446 /* send body */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5447
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5448 b = ngx_calloc_buf(r->pool);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5449 if (b == NULL) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5450 return NGX_ERROR;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5451 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5452
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5453 b->last_buf = (r == r->main) ? 1: 0;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5454 b->last_in_chain = 1;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5455
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5456 b->memory = 1;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5457
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5458 b->pos = (u_char *) "foo";
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5459 b->last = b->pos + 3;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5460
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5461 out.buf = b;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5462 out.next = NULL;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5463
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5464 return ngx_http_output_filter(r, &amp;out);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5465 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5466 </programlisting>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5467
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5468 </section>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5469
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5470
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5471 <section name="Body filters" id="http_body_filters">
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5472
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5473 <para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5474 The function <literal>ngx_http_output_filter(r, cl)</literal> invokes the
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5475 body filter chain by calling the top body filter handler
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5476 <literal>ngx_http_top_body_filter</literal>.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5477 It's assumed that every body handler calls the next handler in chain until
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5478 the final handler <literal>ngx_http_write_filter(r, cl)</literal> is called.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5479 </para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5480
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5481 <para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5482 A body filter handler receives a chain of buffers.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5483 The handler is supposed to process the buffers and pass a possibly new chain to
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5484 the next handler.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5485 It's worth noting that the chain links <literal>ngx_chain_t</literal> of the
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5486 incoming chain belong to the caller.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5487 They should never be reused or changed.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5488 Right after the handler completes, the caller can use its output chain links
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5489 to keep track of the buffers it has sent.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5490 To save the buffer chain or to substitute some buffers before sending further,
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5491 a handler should allocate its own chain links.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5492 </para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5493
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5494 <para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5495 Following is the example of a simple body filter counting the number of
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5496 body bytes.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5497 The result is available as the <literal>$counter</literal> variable which can be
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5498 used in the access log.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5499 </para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5500
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5501 <programlisting>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5502 #include &lt;ngx_config.h&gt;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5503 #include &lt;ngx_core.h&gt;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5504 #include &lt;ngx_http.h&gt;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5505
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5506
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5507 typedef struct {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5508 off_t count;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5509 } ngx_http_counter_filter_ctx_t;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5510
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5511
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5512 static ngx_int_t ngx_http_counter_body_filter(ngx_http_request_t *r,
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5513 ngx_chain_t *in);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5514 static ngx_int_t ngx_http_counter_variable(ngx_http_request_t *r,
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5515 ngx_http_variable_value_t *v, uintptr_t data);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5516 static ngx_int_t ngx_http_counter_add_variables(ngx_conf_t *cf);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5517 static ngx_int_t ngx_http_counter_filter_init(ngx_conf_t *cf);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5518
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5519
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5520 static ngx_http_module_t ngx_http_counter_filter_module_ctx = {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5521 ngx_http_counter_add_variables, /* preconfiguration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5522 ngx_http_counter_filter_init, /* postconfiguration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5523
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5524 NULL, /* create main configuration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5525 NULL, /* init main configuration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5526
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5527 NULL, /* create server configuration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5528 NULL, /* merge server configuration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5529
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5530 NULL, /* create location configuration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5531 NULL /* merge location configuration */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5532 };
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5533
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5534
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5535 ngx_module_t ngx_http_counter_filter_module = {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5536 NGX_MODULE_V1,
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5537 &amp;ngx_http_counter_filter_module_ctx, /* module context */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5538 NULL, /* module directives */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5539 NGX_HTTP_MODULE, /* module type */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5540 NULL, /* init master */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5541 NULL, /* init module */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5542 NULL, /* init process */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5543 NULL, /* init thread */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5544 NULL, /* exit thread */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5545 NULL, /* exit process */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5546 NULL, /* exit master */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5547 NGX_MODULE_V1_PADDING
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5548 };
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5549
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5550
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5551 static ngx_http_output_body_filter_pt ngx_http_next_body_filter;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5552
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5553 static ngx_str_t ngx_http_counter_name = ngx_string("counter");
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5554
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5555
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5556 static ngx_int_t
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5557 ngx_http_counter_body_filter(ngx_http_request_t *r, ngx_chain_t *in)
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5558 {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5559 ngx_chain_t *cl;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5560 ngx_http_counter_filter_ctx_t *ctx;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5561
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5562 ctx = ngx_http_get_module_ctx(r, ngx_http_counter_filter_module);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5563 if (ctx == NULL) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5564 ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_counter_filter_ctx_t));
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5565 if (ctx == NULL) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5566 return NGX_ERROR;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5567 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5568
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5569 ngx_http_set_ctx(r, ctx, ngx_http_counter_filter_module);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5570 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5571
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5572 for (cl = in; cl; cl = cl->next) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5573 ctx->count += ngx_buf_size(cl->buf);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5574 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5575
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5576 return ngx_http_next_body_filter(r, in);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5577 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5578
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5579
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5580 static ngx_int_t
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5581 ngx_http_counter_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v,
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5582 uintptr_t data)
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5583 {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5584 u_char *p;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5585 ngx_http_counter_filter_ctx_t *ctx;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5586
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5587 ctx = ngx_http_get_module_ctx(r, ngx_http_counter_filter_module);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5588 if (ctx == NULL) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5589 v->not_found = 1;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5590 return NGX_OK;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5591 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5592
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5593 p = ngx_pnalloc(r->pool, NGX_OFF_T_LEN);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5594 if (p == NULL) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5595 return NGX_ERROR;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5596 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5597
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5598 v->data = p;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5599 v->len = ngx_sprintf(p, "%O", ctx->count) - p;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5600 v->valid = 1;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5601 v->no_cacheable = 0;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5602 v->not_found = 0;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5603
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5604 return NGX_OK;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5605 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5606
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5607
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5608 static ngx_int_t
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5609 ngx_http_counter_add_variables(ngx_conf_t *cf)
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5610 {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5611 ngx_http_variable_t *var;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5612
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5613 var = ngx_http_add_variable(cf, &amp;ngx_http_counter_name, 0);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5614 if (var == NULL) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5615 return NGX_ERROR;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5616 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5617
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5618 var->get_handler = ngx_http_counter_variable;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5619
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5620 return NGX_OK;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5621 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5622
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5623
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5624 static ngx_int_t
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5625 ngx_http_counter_filter_init(ngx_conf_t *cf)
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5626 {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5627 ngx_http_next_body_filter = ngx_http_top_body_filter;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5628 ngx_http_top_body_filter = ngx_http_counter_body_filter;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5629
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5630 return NGX_OK;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5631 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5632 </programlisting>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5633
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5634 </section>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5635
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5636
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5637 <section name="Building filter modules" id="http_building_filter_modules">
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5638
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5639 <para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5640 When writing a body or header filter, a special care should be taken of the
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5641 filters order.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5642 There's a number of header and body filters registered by nginx standard
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5643 modules.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5644 It's important to register a filter module in the right place in respect to
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5645 other filters.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5646 Normally, filters are registered by modules in their postconfiguration handlers.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5647 The order in which filters are called is obviously the reverse of when they are
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5648 registered.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5649 </para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5650
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5651 <para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5652 A special slot <literal>HTTP_AUX_FILTER_MODULES</literal> for third-party filter
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5653 modules is provided by nginx.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5654 To register a filter module in this slot, the <literal>ngx_module_type</literal>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5655 variable should be set to the value of <literal>HTTP_AUX_FILTER</literal> in
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5656 module's configuration.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5657 </para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5658
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5659 <para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5660 The following example shows a filter module config file assuming it only has
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5661 one source file <literal>ngx_http_foo_filter_module.c</literal>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5662 </para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5663
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5664 <programlisting>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5665 ngx_module_type=HTTP_AUX_FILTER
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5666 ngx_module_name=ngx_http_foo_filter_module
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5667 ngx_module_srcs="$ngx_addon_dir/ngx_http_foo_filter_module.c"
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5668
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5669 . auto/module
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5670 </programlisting>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5671
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5672 </section>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5673
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5674
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5675 <section name="Buffer reuse" id="http_body_buffers_reuse">
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5676
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5677 <para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5678 When issuing or altering a stream of buffers, it's often desirable to reuse the
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5679 allocated buffers.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5680 A standard approach widely adopted in nginx code is to keep two buffer chains
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5681 for this purpose: <literal>free</literal> and <literal>busy</literal>.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5682 The <literal>free</literal> chain keeps all free buffers.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5683 These buffers can be reused.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5684 The <literal>busy</literal> chain keeps all buffers sent by the current
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5685 module which are still in use by some other filter handler.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5686 A buffer is considered in use if its size is greater than zero.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5687 Normally, when a buffer is consumed by a filter, its <literal>pos</literal>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5688 (or <literal>file_pos</literal> for a file buffer) is moved towards
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5689 <literal>last</literal> (<literal>file_last</literal> for a file buffer).
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5690 Once a buffer is completely consumed, it's ready to be reused.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5691 To update the <literal>free</literal> chain with newly freed buffers,
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5692 it's enough to iterate over the <literal>busy</literal> chain and move the zero
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5693 size buffers at the head of it to <literal>free</literal>.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5694 This operation is so common that there is a special function
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5695 <literal>ngx_chain_update_chains(free, busy, out, tag)</literal> which does
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5696 this.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5697 The function appends the output chain <literal>out</literal> to
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5698 <literal>busy</literal> and moves free buffers from the top of
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5699 <literal>busy</literal> to <literal>free</literal>.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5700 Only the buffers with the given <literal>tag</literal> are reused.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5701 This lets a module reuse only the buffers allocated by itself.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5702 </para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5703
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5704 <para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5705 The following example is a body filter inserting the “foo” string before each
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5706 incoming buffer.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5707 The new buffers allocated by the module are reused if possible.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5708 Note that for this example to work properly, it's also required to set up a
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5709 header filter and reset <literal>content_length_n</literal> to -1, which is
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5710 beyond the scope of this section.
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5711 </para>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5712
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5713 <programlisting>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5714 typedef struct {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5715 ngx_chain_t *free;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5716 ngx_chain_t *busy;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5717 } ngx_http_foo_filter_ctx_t;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5718
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5719
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5720 ngx_int_t
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5721 ngx_http_foo_body_filter(ngx_http_request_t *r, ngx_chain_t *in)
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5722 {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5723 ngx_int_t rc;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5724 ngx_buf_t *b;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5725 ngx_chain_t *cl, *tl, *out, **ll;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5726 ngx_http_foo_filter_ctx_t *ctx;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5727
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5728 ctx = ngx_http_get_module_ctx(r, ngx_http_foo_filter_module);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5729 if (ctx == NULL) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5730 ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_foo_filter_ctx_t));
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5731 if (ctx == NULL) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5732 return NGX_ERROR;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5733 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5734
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5735 ngx_http_set_ctx(r, ctx, ngx_http_foo_filter_module);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5736 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5737
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5738 /* create a new chain "out" from "in" with all the changes */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5739
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5740 ll = &amp;out;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5741
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5742 for (cl = in; cl; cl = cl->next) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5743
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5744 /* append "foo" in a reused buffer if possible */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5745
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5746 tl = ngx_chain_get_free_buf(r->pool, &amp;ctx->free);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5747 if (tl == NULL) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5748 return NGX_ERROR;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5749 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5750
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5751 b = tl->buf;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5752 b->tag = (ngx_buf_tag_t) &amp;ngx_http_foo_filter_module;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5753 b->memory = 1;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5754 b->pos = (u_char *) "foo";
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5755 b->last = b->pos + 3;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5756
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5757 *ll = tl;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5758 ll = &amp;tl->next;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5759
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5760 /* append the next incoming buffer */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5761
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5762 tl = ngx_alloc_chain_link(r->pool);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5763 if (tl == NULL) {
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5764 return NGX_ERROR;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5765 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5766
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5767 tl->buf = cl->buf;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5768 *ll = tl;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5769 ll = &amp;tl->next;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5770 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5771
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5772 *ll = NULL;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5773
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5774 /* send the new chain */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5775
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5776 rc = ngx_http_next_body_filter(r, out);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5777
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5778 /* update "busy" and "free" chains for reuse */
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5779
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5780 ngx_chain_update_chains(r->pool, &amp;ctx->free, &amp;ctx->busy, &amp;out,
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5781 (ngx_buf_tag_t) &amp;ngx_http_foo_filter_module);
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5782
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5783 return rc;
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5784 }
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5785 </programlisting>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5786
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5787 </section>
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5788
9550ea66abdd HTTP response section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1959
diff changeset
5789
1939
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5790 <section name="Load balancing" id="http_load_balancing">
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5791
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5792 <para>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5793 The
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5794 <link doc="../http/ngx_http_upstream_module.xml">ngx_http_upstream_module</link>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5795 provides basic functionality to pass requests to remote servers.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5796 This functionality is used by modules that implement specific protocols,
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5797 such as HTTP or FastCGI.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5798 The module also provides an interface for creating custom
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5799 load balancing modules and implements a default round-robin balancing method.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5800 </para>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5801
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5802 <para>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5803 Examples of modules that implement alternative load balancing methods are
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5804 <link doc="../http/ngx_http_upstream_module.xml" id="least_conn"/>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5805 and <link doc="../http/ngx_http_upstream_module.xml" id="hash"/>.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5806 Note that these modules are actually implemented as extensions of the upstream
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5807 module and share a lot of code, such as representation of a server group.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5808 The <link doc="../http/ngx_http_upstream_module.xml" id="keepalive"/> module
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5809 is an example of an independent module, extending upstream functionality.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5810 </para>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5811
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5812 <para>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5813 The
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5814 <link doc="../http/ngx_http_upstream_module.xml">ngx_http_upstream_module</link>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5815 may be configured explicitly by placing the corresponding
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5816 <link doc="../http/ngx_http_upstream_module.xml" id="upstream"/> block into
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5817 the configuration file, or implicitly by using directives
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5818 that accept a URL evaluated at some point to the list of servers,
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5819 for example,
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5820 <link doc="../http/ngx_http_proxy_module.xml" id="proxy_pass"/>.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5821 Only explicit configurations may use an alternative load balancing method.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5822 The upstream module configuration has its own directive context
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5823 <literal>NGX_HTTP_UPS_CONF</literal>.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5824 The structure is defined as follows:
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5825 <programlisting>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5826 struct ngx_http_upstream_srv_conf_s {
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5827 ngx_http_upstream_peer_t peer;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5828 void **srv_conf;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5829
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5830 ngx_array_t *servers; /* ngx_http_upstream_server_t */
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5831
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5832 ngx_uint_t flags;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5833 ngx_str_t host;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5834 u_char *file_name;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5835 ngx_uint_t line;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5836 in_port_t port;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5837 ngx_uint_t no_port; /* unsigned no_port:1 */
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5838
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5839 #if (NGX_HTTP_UPSTREAM_ZONE)
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5840 ngx_shm_zone_t *shm_zone;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5841 #endif
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5842 };
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5843 </programlisting>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5844
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5845 <list type="bullet">
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5846
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5847 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5848 <literal>srv_conf</literal> — configuration context of upstream modules
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5849 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5850
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5851 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5852 <literal>servers</literal> — array of
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5853 <literal>ngx_http_upstream_server_t</literal>, the result of parsing a set of
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5854 <link doc="../http/ngx_http_upstream_module.xml" id="server"/> directives
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5855 in the <literal>upstream</literal> block
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5856 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5857
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5858 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5859 <literal>flags</literal> — flags that mostly mark which features
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5860 (configured as parameters of
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5861 the <link doc="../http/ngx_http_upstream_module.xml" id="server"/> directive)
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5862 are supported by the particular load balancing method.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5863
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5864 <list type="bullet">
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5865
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5866 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5867 <literal>NGX_HTTP_UPSTREAM_CREATE</literal> — used to distinguish explicitly
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5868 defined upstreams from automatically created by
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5869 <link doc="../http/ngx_http_proxy_module.xml" id="proxy_pass"/> and “friends”
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5870 (FastCGI, SCGI, etc.)
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5871 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5872
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5873 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5874 <literal>NGX_HTTP_UPSTREAM_WEIGHT</literal> — “<literal>weight</literal>”
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5875 is supported
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5876 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5877
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5878 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5879 <literal>NGX_HTTP_UPSTREAM_MAX_FAILS</literal> — “<literal>max_fails</literal>”
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5880 is supported
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5881 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5882
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5883 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5884 <literal>NGX_HTTP_UPSTREAM_FAIL_TIMEOUT</literal> —
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5885 “<literal>fail_timeout</literal>” is supported
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5886 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5887
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5888 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5889 <literal>NGX_HTTP_UPSTREAM_DOWN</literal> — “<literal>down</literal>”
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5890 is supported
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5891 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5892
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5893 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5894 <literal>NGX_HTTP_UPSTREAM_BACKUP</literal> — “<literal>backup</literal>”
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5895 is supported
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5896 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5897
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5898 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5899 <literal>NGX_HTTP_UPSTREAM_MAX_CONNS</literal> — “<literal>max_conns</literal>”
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5900 is supported
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5901 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5902
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5903 </list>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5904
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5905 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5906
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5907 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5908 <literal>host</literal> — the name of an upstream
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5909 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5910
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5911 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5912 <literal>file_name, line</literal> — the name of the configuration file
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5913 and the line where the <literal>upstream</literal> block is located
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5914 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5915
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5916 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5917 <literal>port</literal> and <literal>no_port</literal> — unused by explicit
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5918 upstreams
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5919 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5920
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5921 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5922 <literal>shm_zone</literal> — a shared memory zone used by this upstream, if any
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5923 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5924
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5925 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5926 <literal>peer</literal> — an object that holds generic methods for
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5927 initializing upstream configuration:
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5928
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5929 <programlisting>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5930 typedef struct {
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5931 ngx_http_upstream_init_pt init_upstream;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5932 ngx_http_upstream_init_peer_pt init;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5933 void *data;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5934 } ngx_http_upstream_peer_t;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5935 </programlisting>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5936 A module that implements a load balancing algorithm must set these
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5937 methods and initialize private <literal>data</literal>.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5938 If <literal>init_upstream</literal> was not initialized during configuration
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5939 parsing, <literal>ngx_http_upstream_module</literal> sets it to default
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5940 <literal>ngx_http_upstream_init_round_robin</literal>.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5941
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5942 <list type="bullet">
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5943 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5944 <literal>init_upstream(cf, us)</literal> — configuration-time
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5945 method responsible for initializing a group of servers and
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5946 initializing the <literal>init()</literal> method in case of success.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5947 A typical load balancing module uses a list of servers in the upstream block
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5948 to create some efficient data structure that it uses and saves own
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5949 configuration to the <literal>data</literal> field.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5950 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5951
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5952 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5953 <literal>init(r, us)</literal> — initializes per-request
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5954 <literal>ngx_http_upstream_peer_t.peer</literal> (not to be confused with the
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5955 <literal>ngx_http_upstream_srv_conf_t.peer</literal> described above which
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5956 is per-upstream) structure that is used for load balancing.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5957 It will be passed as <literal>data</literal> argument to all callbacks that
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5958 deal with server selection.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5959 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5960 </list>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5961
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5962 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5963 </list>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5964 </para>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5965
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5966 <para>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5967 When nginx has to pass a request to another host for processing, it uses
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5968 a configured load balancing method to obtain an address to connect to.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5969 The method is taken from the
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5970 <literal>ngx_http_upstream_peer_t.peer</literal> object
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5971 of type <literal>ngx_peer_connection_t</literal>:
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5972 <programlisting>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5973 struct ngx_peer_connection_s {
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5974 [...]
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5975
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5976 struct sockaddr *sockaddr;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5977 socklen_t socklen;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5978 ngx_str_t *name;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5979
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5980 ngx_uint_t tries;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5981
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5982 ngx_event_get_peer_pt get;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5983 ngx_event_free_peer_pt free;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5984 ngx_event_notify_peer_pt notify;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5985 void *data;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5986
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5987 #if (NGX_SSL || NGX_COMPAT)
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5988 ngx_event_set_peer_session_pt set_session;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5989 ngx_event_save_peer_session_pt save_session;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5990 #endif
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5991
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5992 [..]
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5993 };
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5994 </programlisting>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5995
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5996 The structure has the following fields:
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5997
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5998 <list type="bullet">
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
5999 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6000 <literal>sockaddr</literal>, <literal>socklen</literal>,
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6001 <literal>name</literal> — address of an upstream server to connect to;
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6002 this is the output parameter of a load balancing method
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6003 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6004
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6005 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6006 <literal>data</literal> — per-request load balancing method data; keeps the
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6007 state of selection algorithm and usually includes the link to upstream
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6008 configuration.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6009 It will be passed as an argument to all methods that deal with server selection
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6010 (see below)
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6011 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6012
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6013 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6014 <literal>tries</literal> — allowed
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6015 <link doc="../http/ngx_http_proxy_module.xml" id="proxy_next_upstream_tries">number</link>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6016 of attempts to connect to an upstream.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6017 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6018
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6019 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6020 <literal>get</literal>, <literal>free</literal>, <literal>notify</literal>,
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6021 <literal>set_session</literal>, and <literal>save_session</literal>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6022 - methods of the load balancing module, see description below
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6023 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6024
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6025 </list>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6026
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6027 </para>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6028
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6029 <para>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6030 All methods accept at least two arguments: peer connection object
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6031 <literal>pc</literal> and the <literal>data</literal> created by
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6032 <literal>ngx_http_upstream_srv_conf_t.peer.init()</literal>.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6033 Note that in general case it may differ from <literal>pc.data</literal> due
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6034 to “chaining” of load balancing modules.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6035 </para>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6036
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6037 <para>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6038
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6039 <list type="bullet">
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6040 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6041 <literal>get(pc, data)</literal> — the method is called when the upstream
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6042 module is ready to pass a request to an upstream server and needs to know
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6043 its address.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6044 The method is responsible to fill in the <literal>sockaddr</literal>,
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6045 <literal>socklen</literal>, and <literal>name</literal> fields of
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6046 <literal>ngx_peer_connection_t</literal> structure.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6047 The return value may be one of:
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6048
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6049 <list type="bullet">
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6050
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6051 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6052 <literal>NGX_OK</literal> — server was selected
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6053 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6054
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6055 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6056 <literal>NGX_ERROR</literal> — internal error occurred
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6057 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6058
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6059 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6060 <literal>NGX_BUSY</literal> — there are no available servers at the moment.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6061 This can happen due to many reasons, such as: dynamic server group is empty,
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6062 all servers in the group are in the failed state,
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6063 all servers in the group are already
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6064 handling the maximum number of connections or similar.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6065 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6066
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6067 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6068 <literal>NGX_DONE</literal> — this is set by the <literal>keepalive</literal>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6069 module to indicate that the underlying connection was reused and there is no
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6070 need to create a new connection to the upstream server.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6071 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6072
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6073 <!--
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6074 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6075 <literal>NGX_ABORT</literal> — this is set by the <literal>queue</literal>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6076 module to indicate that the request was queued and the further processing
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6077 of this request should be postponed.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6078 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6079 -->
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6080
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6081 </list>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6082
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6083 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6084
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6085 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6086 <literal>free(pc, data, state)</literal> — the method is called when an
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6087 upstream module has finished work with a particular server.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6088 The <literal>state</literal> argument is the status of upstream connection
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6089 completion.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6090 This is a bitmask, the following values may be set:
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6091 <literal>NGX_PEER_FAILED</literal> — this attempt is considered
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6092 <link doc="../http/ngx_http_upstream_module.xml" id="max_fails">unsuccessful</link>,
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6093 <literal>NGX_PEER_NEXT</literal> — a special case with codes 403 and 404
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6094 (see link above), which are not considered a failure.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6095 <literal>NGX_PEER_KEEPALIVE</literal>.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6096 Also, <literal>tries</literal> counter is decremented by this method.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6097 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6098
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6099 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6100 <literal>notify(pc, data, type)</literal> — currently unused
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6101 in the OSS version.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6102 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6103
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6104 <listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6105 <literal>set_session(pc, data)</literal> and
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6106 <literal>save_session(pc, data)</literal>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6107 — SSL-specific methods that allow to cache sessions to upstream
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6108 servers.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6109 The implementation is provided by the round-robin balancing method.
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6110 </listitem>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6111
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6112 </list>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6113
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6114 </para>
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6115
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
6116 </section>
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
6117
1939
c1b0169e8f54 Added the "Load balancing" section of the development guide.
Vladimir Homutov <vl@nginx.com>
parents: 1936
diff changeset
6118 </section>
1929
7f290929b32d HTTP section of the development guide.
Roman Arutyunyan <arut@nginx.com>
parents: 1928
diff changeset
6119
1899
b86cfece30c3 Added development guide.
Vladimir Homutov <vl@nginx.com>
parents:
diff changeset
6120 </article>