<?xml version="1.0"?>

<!DOCTYPE module SYSTEM "../../../../dtd/module.dtd">

<module name="Module ngx_http_fastcgi_module"
        link="/en/docs/http/ngx_http_fastcgi_module.html"
        lang="en">

<section id="summary">

<para>
The <literal>ngx_http_fastcgi_module</literal> module allows to pass
requests to a FastCGI server.
</para>

</section>


<section id="example" name="Example Configuration">

<para>
<example>
location / {
    fastcgi_pass  localhost:9000;
    fastcgi_index index.php;

    fastcgi_param SCRIPT_FILENAME /home/www/scripts/php$fastcgi_script_name;
    fastcgi_param QUERY_STRING    $query_string;
    fastcgi_param REQUEST_METHOD  $request_method;
    fastcgi_param CONTENT_TYPE    $content_type;
    fastcgi_param CONTENT_LENGTH  $content_length;
}
</example>
</para>

</section>


<section id="directives" name="Directives">

<directive name="fastcgi_buffer_size">
<syntax><value>size</value></syntax>
<default>4k|8k</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Sets <value>size</value> of the buffer used for reading the first part
of a response received from the FastCGI server.
This part usually contains a small response header.
By default, the buffer size is equal to the size of one
buffer set by the <link id="fastcgi_buffers"/> directive.
It can be made smaller however.
</para>

</directive>


<directive name="fastcgi_buffers">
<syntax><value>number</value> <value>size</value></syntax>
<default>8 4k|8k</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Sets the <value>number</value> and <value>size</value> of
buffers used for reading a response from the FastCGI server,
for a single connection.
By default, the buffer size is equal to one memory page.
This is either 4K or 8K, depending on a platform.
</para>

</directive>


<directive name="fastcgi_cache">
<syntax><value>zone</value> | <literal>off</literal></syntax>
<default>off</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Defines a zone used for caching.
The same zone can be used in several places.
The <literal>off</literal> parameter disables caching inherited
from the previous configuration level.
</para>

</directive>


<directive name="fastcgi_cache_bypass">
<syntax><value>string</value> ...</syntax>
<default/>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Defines conditions under which the response will not be taken from a cache.
If at least one value of the string parameters is not empty and is not
equal to “0” then the response will not be taken from the cache:
<example>
fastcgi_cache_bypass $cookie_nocache $arg_nocache$arg_comment;
fastcgi_cache_bypass $http_pragma    $http_authorization;
</example>
Can be used along with the <link id="fastcgi_no_cache"/> directive.
</para>

</directive>


<directive name="fastcgi_cache_key">
<syntax><value>string</value></syntax>
<default/>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Defines a key for caching, for example
<example>
fastcgi_cache_key localhost:9000$request_uri;
</example>
</para>

</directive>


<directive name="fastcgi_cache_lock">
<syntax><literal>on</literal> | <literal>off</literal></syntax>
<default>off</default>
<context>http</context>
<context>server</context>
<context>location</context>
<appeared-in>1.1.12</appeared-in>

<para>
When enabled, only one request at a time will be allowed to populate
a new cache element identified according to the <link id="fastcgi_cache_key"/>
directive by passing a request to a FastCGI server.
Other requests of the same cache element will either wait
for a response to appear in the cache, or the cache lock for
this element to be released, up to the time set by the
<link id="fastcgi_cache_lock_timeout"/> directive.
</para>

</directive>


<directive name="fastcgi_cache_lock_timeout">
<syntax><value>time</value></syntax>
<default>5s</default>
<context>http</context>
<context>server</context>
<context>location</context>
<appeared-in>1.1.12</appeared-in>

<para>
Sets a timeout for <link id="fastcgi_cache_lock"/>.
</para>

</directive>


<directive name="fastcgi_cache_min_uses">
<syntax><value>number</value></syntax>
<default>1</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Sets the <value>number</value> of requests after which the response
will be cached.
</para>

</directive>


<directive name="fastcgi_cache_path">
<syntax>
  <value>path</value>
  [<literal>levels</literal>=<value>levels</value>]
  <literal>keys_zone</literal>=<value>name</value>:<value>size</value>
  [<literal>inactive</literal>=<value>time</value>]
  [<literal>max_size</literal>=<value>size</value>]</syntax>
<default/>
<context>http</context>

<para>
Sets path and other parameters of a cache.
Cache data are stored in files.
Both the key and file name in a cache are a result of
applying the MD5 function to the proxied URL.

The <literal>levels</literal> parameter defines hierarchy levels of a cache.
For example, in the following configuration
<example>
fastcgi_cache_path /data/nginx/cache levels=1:2 keys_zone=one:10m;
</example>
file names in a cache will look like this:
<example>
/data/nginx/cache/<emphasis>c</emphasis>/<emphasis>29</emphasis>/b7f54b2df7773722d382f4809d650<emphasis>29c</emphasis>
</example>
</para>

<para>
A cached response is first written to a temporary file, then a file is renamed.
Starting from version 0.8.9 temporary files and the cache can be put on
different file systems but be aware that in this case a file is copied
across two file systems instead of the cheap rename operation.
It is thus recommended that for any given location both cache and a directory
holding temporary files set by the <link id="fastcgi_temp_path"/> directive
are put on the same file system.
</para>

<para>
In addition, all active keys and information about data are stored
in a shared memory zone, whose <value>name</value> and <value>size</value>
are configured by the <literal>keys_zone</literal> parameter.
Cached data that are not accessed during the time specified by the
<literal>inactive</literal> parameter get removed from the cache
regardless of their freshness.
By default, <literal>inactive</literal> is set to 10 minutes.
</para>

<para>
The special process “cache manager” monitors the maximum cache size set
by the <literal>max_size</literal> parameter;
when this size is exceeded it removes the least recently used data.
</para>

</directive>


<directive name="fastcgi_cache_use_stale">
<syntax>
  <literal>error</literal> |
  <literal>timeout</literal> |
  <literal>invalid_header</literal> |
  <literal>updating</literal> |
  <literal>http_500</literal> |
  <literal>http_503</literal> |
  <literal>http_404</literal> |
  <literal>off</literal>
  ...</syntax>
<default>off</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
If an error occurs while working with the FastCGI server it is possible
to use a stale cached response.
This directives determines in which cases it is permitted.
The directive’s parameters match those of the
<link id="fastcgi_next_upstream"/> directive.
Additionally, the <literal>updating</literal> parameter permits
to use a stale cached response if it is currently being updated.
</para>

</directive>


<directive name="fastcgi_cache_valid">
<syntax>[<value>code</value> ...] <value>time</value></syntax>
<default/>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Sets caching time for different response codes.
For example, the following directives
<example>
fastcgi_cache_valid 200 302 10m;
fastcgi_cache_valid 404      1m;
</example>
set 10 minutes of caching for responses with codes 200 and 302,
and 1 minute for responses with code 404.
</para>

<para>
If only caching <value>time</value> is specified
<example>
fastcgi_cache_valid 5m;
</example>
then only 200, 301, and 302 responses are cached.
</para>

<para>
In addition, it can be specified to cache any responses using the
<literal>any</literal> parameter:
<example>
fastcgi_cache_valid 200 302 10m;
fastcgi_cache_valid 301      1h;
fastcgi_cache_valid any      1m;
</example>
</para>

</directive>


<directive name="fastcgi_connect_timeout">
<syntax><value>time</value></syntax>
<default>60s</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Defines a timeout for establishing a connection with the FastCGI server.
It should be noted that this timeout cannot usually exceed 75 seconds.
</para>

</directive>


<directive name="fastcgi_hide_header">
<syntax><value>field</value></syntax>
<default/>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
By default,
nginx does not pass the header fields <header>Status</header> and
<header>X-Accel-...</header> from the response of the FastCGI
server to a client.
The <literal>fastcgi_hide_header</literal> directive sets additional fields
that will not be passed.
If, on the contrary, the passing of fields needs to be permitted,
the <link id="fastcgi_pass_header"/> directive can be used.
</para>

</directive>


<directive name="fastcgi_ignore_client_abort">
<syntax><literal>on</literal> | <literal>off</literal></syntax>
<default>off</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Determines should the connection with the FastCGI server be
closed if a client closes a connection without waiting
for a response.
</para>

</directive>


<directive name="fastcgi_ignore_headers">
<syntax><value>field</value> ...</syntax>
<default/>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Disables processing of certain response header fields from the FastCGI server.
The following fields can be ignored: <header>X-Accel-Redirect</header>,
<header>X-Accel-Expires</header>, <header>X-Accel-Limit-Rate</header> (1.1.6),
<header>X-Accel-Buffering</header> (1.1.6),
<header>X-Accel-Charset</header> (1.1.6), <header>Expires</header>,
<header>Cache-Control</header>, and <header>Set-Cookie</header> (0.8.44).
</para>

</directive>


<directive name="fastcgi_index">
<syntax><value>name</value></syntax>
<default/>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Sets a file name that will be appended after a URI that ends with
a slash, in the value of the <var>$fastcgi_script_name</var> variable.
For example, with these settings
<example>
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME /home/www/scripts/php$fastcgi_script_name;
</example>
and the “<literal>/page.php</literal>” request,
the <literal>SCRIPT_FILENAME</literal> parameter will be equal to
“<literal>/home/www/scripts/php/page.php</literal>”,
and with the “<literal>/</literal>” request it will be equal to
“<literal>/home/www/scripts/php/index.php</literal>”.
</para>

</directive>


<directive name="fastcgi_intercept_errors">
<syntax><literal>on</literal> | <literal>off</literal></syntax>
<default>off</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Determines whether FastCGI server responses with codes greater than or equal
to 400 should be passed to a client or be redirected to nginx for processing
using the <link doc="ngx_http_core_module.xml" id="error_page"/> directive.
</para>

</directive>


<directive name="fastcgi_keep_conn">
<syntax><literal>on</literal> | <literal>off</literal></syntax>
<default>off</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
By default, a FastCGI server will close a connection right after
sending the response.
When set to the value <literal>on</literal>, nginx will instruct
a FastCGI server to keep connections open.
This in particular is necessary for 
<link doc="ngx_http_upstream_module.xml" id="keepalive"/>
connections to FastCGI servers to function.
</para>

</directive>


<directive name="fastcgi_next_upstream">
<syntax>
  <literal>error</literal> |
  <literal>timeout</literal> |
  <literal>invalid_header</literal> |
  <literal>http_500</literal> |
  <literal>http_503</literal> |
  <literal>http_404</literal> |
  <literal>off</literal>
  ...</syntax>
<default>error timeout</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Specifies in which cases a request should be passed to the next server:
<list type="tag">

<tag-name><literal>error</literal></tag-name>
<tag-desc>an error occurred while establishing a connection with the
server, passing it a request, or reading the response header;</tag-desc>

<tag-name><literal>timeout</literal></tag-name>
<tag-desc>a timeout has occurred while establishing a connection with the
server, passing it a request, or reading the response header;</tag-desc>

<tag-name><literal>invalid_header</literal></tag-name>
<tag-desc>a server returned empty or invalid response;</tag-desc>

<tag-name><literal>http_500</literal></tag-name>
<tag-desc>a server returned a response with the code 500;</tag-desc>

<tag-name><literal>http_503</literal></tag-name>
<tag-desc>a server returned a response with the code 503;</tag-desc>

<tag-name><literal>http_404</literal></tag-name>
<tag-desc>a server returned a response with the code 404;</tag-desc>

<tag-name><literal>off</literal></tag-name>
<tag-desc>disables passing a request to the next server.</tag-desc>

</list>
</para>

<para>
It should be understood that passing a request to the next server is
only possible if a client was not sent anything yet.
That is, if an error or a timeout occurs in the middle of
transferring a response, fixing this is impossible.
</para>

</directive>


<directive name="fastcgi_no_cache">
<syntax><value>string</value> ...</syntax>
<default/>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Defines conditions under which the response will not be saved to a cache.
If at least one value of the string parameters is not empty and is not
equal to “0” then the response will not be saved:
<example>
fastcgi_no_cache $cookie_nocache $arg_nocache$arg_comment;
fastcgi_no_cache $http_pragma    $http_authorization;
</example>
Can be used along with the <link id="fastcgi_cache_bypass"/> directive.
</para>

</directive>


<directive name="fastcgi_param">
<syntax>
    <value>parameter</value> <value>value</value>
    [<literal>if_not_empty</literal>]</syntax>
<default/>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Sets a <value>parameter</value> that should be passed to the FastCGI server.
A <value>value</value> can contain text, variables, and their combination.
These directives are inherited from the previous level if and
only if there are no
<literal>fastcgi_param</literal>
directives defined on the current level.
</para>

<para>
The following example shows the minimum required settings for PHP:
<example>
fastcgi_param SCRIPT_FILENAME /home/www/scripts/php$fastcgi_script_name;
fastcgi_param QUERY_STRING    $query_string;
</example>
</para>

<para>
The <literal>SCRIPT_FILENAME</literal> parameter is used in PHP for
determining the script name, and the <literal>QUERY_STRING</literal>
parameter is used to pass request parameters.
</para>

<para>
For scripts that process <literal>POST</literal> requests, the
following three parameters are also required:
<example>
fastcgi_param REQUEST_METHOD  $request_method;
fastcgi_param CONTENT_TYPE    $content_type;
fastcgi_param CONTENT_LENGTH  $content_length;
</example>
</para>

<para>
If PHP was built with the <literal>--enable-force-cgi-redirect</literal>
configuration parameter, the <literal>REDIRECT_STATUS</literal> parameter
should also be passed with the value “200”:
<example>
fastcgi_param REDIRECT_STATUS 200;
</example>
</para>

<para>
If a directive is specified with <literal>if_not_empty</literal> (1.1.11) then
such a parameter will not be passed to the server until its value is not empty:
<example>
fastcgi_param HTTPS           $https if_not_empty;
</example>
</para>

</directive>


<directive name="fastcgi_pass">
<syntax><value>address</value></syntax>
<default/>
<context>location</context>
<context>if in location</context>

<para>
Sets an address of the FastCGI server.
An address can be specified as a domain name or an address, and a port,
for example,
<example>
fastcgi_pass localhost:9000;
</example>
or as a UNIX-domain socket path:
<example>
fastcgi_pass unix:/tmp/fastcgi.socket;
</example>
</para>

<para>
If a domain name resolves to several addresses, all of them will be
used in a round-robin fashion.
In addition, an address can be specified as a
<link doc="ngx_http_upstream_module.xml">server group</link>.
</para>

</directive>


<directive name="fastcgi_pass_header">
<syntax><value>field</value></syntax>
<default/>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Permits to pass <link id="fastcgi_hide_header">otherwise disabled</link> header
fields from the FastCGI server to a client.
</para>

</directive>


<directive name="fastcgi_read_timeout">
<syntax><value>time</value></syntax>
<default>60s</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Defines a timeout for reading a response from the FastCGI server.
A timeout is only set between two successive read operations,
not for the transmission of the whole response.
If a FastCGI server does not transmit anything within this time,
a connection is closed.
</para>

</directive>


<directive name="fastcgi_send_timeout">
<syntax><value>time</value></syntax>
<default>60s</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Sets a timeout for transmitting a request to the FastCGI server.
A timeout is only set between two successive write operations,
not for the transmission of the whole request.
If a FastCGI server does not receive anything within this time,
a connection is closed.
</para>

</directive>


<directive name="fastcgi_split_path_info">
<syntax><value>regex</value></syntax>
<default/>
<context>location</context>

<para>
Defines a regular expression that captures a value for the
<var>$fastcgi_path_info</var> variable.
A regular expression should have two captures, the first becomes
a value of the <var>$fastcgi_script_name</var> variable, the second
becomes a value of the <var>$fastcgi_path_info</var> variable.
For example, with these settings
<example>
location ~ ^(.+\.php)(.*)$ {
    fastcgi_split_path_info       ^(.+\.php)(.*)$;
    fastcgi_param SCRIPT_FILENAME /path/to/php$fastcgi_script_name;
    fastcgi_param PATH_INFO       $fastcgi_path_info;
</example>
and the “<literal>/show.php/article/0001</literal>” request,
the <literal>SCRIPT_FILENAME</literal> parameter will be equal to
“<literal>/path/to/php/show.php</literal>”, and the
<literal>PATH_INFO</literal> parameter will be equal to
“<literal>/article/0001</literal>”.
</para>

</directive>


<directive name="fastcgi_store">
<syntax>
    <literal>on</literal> |
    <literal>off</literal> |
    <value>string</value></syntax>
<default>off</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Enables saving of files to a disk.
The <literal>on</literal> parameter saves files with paths
corresponding to the directives
<link doc="ngx_http_core_module.xml" id="alias"/> or
<link doc="ngx_http_core_module.xml" id="root"/>.
The <literal>off</literal> parameter disables saving of files.
In addition, the file name can be set explicitly using the
<value>string</value> with variables:
<example>
fastcgi_store /data/www$original_uri;
</example>
</para>

<para>
The modification time of files is set according to the received
<header>Last-Modified</header> response header field.
A response is first written to a temporary file, then a file is renamed.
Starting from version 0.8.9 temporary files and the persistent store
can be put on different file systems but be aware that in this case
a file is copied across two file systems instead of the cheap rename operation.
It is thus recommended that for any given location both saved files and a
directory holding temporary files set by the <link id="fastcgi_temp_path"/>
directive are put on the same file system.
</para>

<para>
This directive can be used to create local copies of static unchangeable
files, e.g.:
<example>
location /images/ {
    root                   /data/www;
    open_file_cache_errors off;
    error_page             404 = /fetch$uri;
}

location /fetch/ {
    internal;

    fastcgi_pass         backend:9000;
    ...

    fastcgi_store        on;
    fastcgi_store_access user:rw group:rw all:r;
    fastcgi_temp_path    /data/temp;

    alias                /data/www/;
}
</example>
</para>

</directive>


<directive name="fastcgi_store_access">
<syntax><value>users</value>:<value>permissions</value> ...</syntax>
<default>user:rw</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Sets access permissions for newly created files and directories, e.g.:
<example>
fastcgi_store_access user:rw group:rw all:r;
</example>
</para>

<para>
If any <literal>group</literal> or <literal>all</literal> access permissions
are specified then <literal>user</literal> permissions may be omitted:
<example>
fastcgi_store_access group:rw all:r;
</example>
</para>

</directive>


<directive name="fastcgi_temp_path">
<syntax>
    <value>path</value>
    [<value>level1</value>
    [<value>level2</value>
    [<value>level3</value>]]]</syntax>
<default>fastcgi_temp</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Defines a directory for storing temporary files
received from another server.
Up to three-level subdirectory hierarchy can be used underneath the specified
directory.
For example, in the following configuration
<example>
fastcgi_temp_path /spool/nginx/fastcgi_temp 1 2;
</example>
a temporary file might look like this:
<example>
/spool/nginx/fastcgi_temp/<emphasis>7</emphasis>/<emphasis>45</emphasis>/00000123<emphasis>457</emphasis>
</example>
</para>

</directive>

</section>


<section id="parameters" name="Parameters Passed to a FastCGI Server">

<para>
HTTP request header fields are passed to the FastCGI server as parameters.
In applications and scripts running as FastCGI servers,
these parameters are usually made available as environment variables.
For example, the <header>User-Agent</header> header field is passed as the
<literal>HTTP_USER_AGENT</literal> parameter.
In addition to HTTP request header fields it is possible to pass arbitrary
parameters using the <link id="fastcgi_param"/> directive.
</para>

</section>


<section id="variables" name="Embedded Variables">

<para>
The <literal>ngx_http_fastcgi_module</literal> module supports embedded variables
that can be used to set parameters using the
<link id="fastcgi_param"/> directive:
<list type="tag">

<tag-name><var>$fastcgi_script_name</var></tag-name>
<tag-desc>
request URI or, if a URI ends with a slash, request URI with an index file
name configured by the <link id="fastcgi_index"/> directive appended to it.
This variable can be used to set the
<literal>SCRIPT_FILENAME</literal> and <literal>PATH_TRANSLATED</literal>
parameters that determine the script name in PHP.
For example, for the “<literal>/info/</literal>” request with the
following directives
<example>
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME /home/www/scripts/php$fastcgi_script_name;
</example>
the <literal>SCRIPT_FILENAME</literal> parameter will be equal to
“<literal>/home/www/scripts/php/info/index.php</literal>”.

<para>
When using the <link id="fastcgi_split_path_info"/> directive,
the <var>$fastcgi_script_name</var> variable equals to the value of
the first capture set by the directive.
</para>
</tag-desc>

<tag-name><var>$fastcgi_path_info</var></tag-name>
<tag-desc>the value of the second capture set by the
<link id="fastcgi_split_path_info"/> directive.
This variable can be used to set the
<literal>PATH_INFO</literal> parameter.
</tag-desc>

</list>
</para>

</section>

</module>