<?xml version="1.0"?>

<!--
  Copyright (C) Igor Sysoev
  Copyright (C) Nginx, Inc.
  -->

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

<module name="Module ngx_http_fastcgi_module"
        link="/en/docs/http/ngx_http_fastcgi_module.html"
        lang="en"
        rev="13">

<section id="summary">

<para>
The <literal>ngx_http_fastcgi_module</literal> module allows passing
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_bind">
<syntax><value>address</value> | <literal>off</literal></syntax>
<default/>
<context>http</context>
<context>server</context>
<context>location</context>
<appeared-in>0.8.22</appeared-in>

<para>
Makes outgoing connections to a FastCGI server originate
from the specified local IP <value>address</value>.
Parameter value can contain variables (1.3.12).
The special value <literal>off</literal> (1.3.12) cancels the effect
of the <literal>fastcgi_bind</literal> directive
inherited from the previous configuration level, which allows the
system to auto-assign the local IP address.
</para>

</directive>


<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 the <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_buffering">
<syntax><literal>on</literal> | <literal>off</literal></syntax>
<default>on</default>
<context>http</context>
<context>server</context>
<context>location</context>
<appeared-in>1.5.6</appeared-in>

<para>
Enables or disables buffering of responses from the FastCGI server.
</para>

<para>
When buffering is enabled, nginx receives a response from the FastCGI server
as soon as possible, saving it into the buffers set by the
<link id="fastcgi_buffer_size"/> and <link id="fastcgi_buffers"/> directives.
If the whole response does not fit into memory, a part of it can be saved
to a <link id="fastcgi_temp_path">temporary file</link> on the disk.
Writing to temporary files is controlled by the
<link id="fastcgi_max_temp_file_size"/> and
<link id="fastcgi_temp_file_write_size"/> directives.
</para>

<para>
When buffering is disabled, a response is passed to a client synchronously,
immediately as it is received.
nginx will not try to read the whole response from the FastCGI server.
The maximum size of the data that nginx can receive from the server
at a time is set by the <link id="fastcgi_buffer_size"/> directive.
</para>

<para>
Buffering can also be enabled or disabled by passing
“<literal>yes</literal>” or “<literal>no</literal>” in the
<header>X-Accel-Buffering</header> response header field.
This capability can be disabled using the
<link id="fastcgi_ignore_headers"/> directive.
</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_busy_buffers_size">
<syntax><value>size</value></syntax>
<default>8k|16k</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
When <link id="fastcgi_buffering">buffering</link> of responses from the FastCGI
server is enabled, limits the total <value>size</value> of buffers that
can be busy sending a response to the client while the response is not
yet fully read.
In the mean time, the rest of the buffers can be used for reading a response
and, if needed, buffering part of a response to a temporary file.
By default, <value>size</value> is limited by the size of two buffers set by the
<link id="fastcgi_buffer_size"/> and <link id="fastcgi_buffers"/> directives.
</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 shared memory 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_methods">
<syntax>
    <literal>GET</literal> |
    <literal>HEAD</literal> |
    <literal>POST</literal>
    ...</syntax>
<default>GET HEAD</default>
<context>http</context>
<context>server</context>
<context>location</context>
<appeared-in>0.7.59</appeared-in>

<para>
If the client request method is listed in this directive then
the response will be cached.
“<literal>GET</literal>” and “<literal>HEAD</literal>” methods are always
added to the list, though it is recommended to specify them explicitly.
See also the <link id="fastcgi_no_cache"/> directive.
</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>]
    [<literal>loader_files</literal>=<value>number</value>]
    [<literal>loader_sleep</literal>=<value>time</value>]
    [<literal>loader_threshold</literal>=<value>time</value>]</syntax>
<default/>
<context>http</context>

<para>
Sets the 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,
and then the file is renamed.
Starting from version 0.8.9, temporary files and the cache can be put on
different file systems.
However, be aware that in this case a file is copied
across two file systems instead of the cheap renaming 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 “cache manager” process 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>

<para>
A minute after the start the special “cache loader” process is activated.
It loads information about previously cached data stored on file system
into a cache zone.
The loading is done in iterations.
During one iteration no more than <literal>loader_files</literal> items
are loaded (by default, 100).
Besides, the duration of one iteration is limited by the
<literal>loader_threshold</literal> parameter (by default, 200 milliseconds).
Between iterations, a pause configured by the <literal>loader_sleep</literal>
parameter (by default, 50 milliseconds) is made.
</para>

</directive>


<directive name="fastcgi_cache_purge">
<syntax>string ...</syntax>
<default/>
<context>http</context>
<context>server</context>
<context>location</context>
<appeared-in>1.5.7</appeared-in>

<para>
Defines conditions under which the request will be considered a cache
purge request.
If at least one value of the string parameters is not empty and is not equal
to “0” then the cache entry with a corresponding
<link id="fastcgi_cache_key">cache key</link> is removed.
The result of successful operation is indicated by returning
the <http-status code="204" text="No Content"/> response.
</para>

<para>
If the <link id="fastcgi_cache_key">cache key</link> of a purge request ends
with an asterisk (“<literal>*</literal>”), all cache entries matching the
wildcard key will be removed from the cache.
</para>

<para>
Example configuration:
<example>
fastcgi_cache_path /data/nginx/cache keys_zone=cache_zone:10m;

map $request_method $purge_method {
    PURGE   1;
    default 0;
}

server {
    ...
    location / {
        fastcgi_pass backend;
        fastcgi_cache cache_zone;
        fastcgi_cache_key $uri;
        fastcgi_cache_purge $purge_method;
    }
}
</example>
<note>
This functionality is available as part of our <commercial_version/> only.
</note>
</para>

</directive>


<directive name="fastcgi_cache_revalidate">
<syntax><literal>on</literal> | <literal>off</literal></syntax>
<default>off</default>
<context>http</context>
<context>server</context>
<context>location</context>
<appeared-in>1.5.7</appeared-in>

<para>
Enables revalidation of expired cache items using conditional requests with
the <header>If-Modified-Since</header> header field.
</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_403</literal> |
    <literal>http_404</literal> |
    <literal>off</literal>
    ...</syntax>
<default>off</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Determines in which cases a stale cached response can be used
when an error occurs during communication with the FastCGI server.
The directive’s parameters match the parameters of the
<link id="fastcgi_next_upstream"/> directive.
</para>

<para>
Additionally, the <literal>updating</literal> parameter permits
using a stale cached response if it is currently being updated.
This allows minimizing the number of accesses to FastCGI servers
when updating cached data.
</para>

<para>
To minimize the number of accesses to FastCGI servers when
populating a new cache element, the <link id="fastcgi_cache_lock"/>
directive can be used.
</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, the <literal>any</literal> parameter can be specified
to cache any responses:
<example>
fastcgi_cache_valid 200 302 10m;
fastcgi_cache_valid 301      1h;
fastcgi_cache_valid any      1m;
</example>
</para>

<para>
Parameters of caching can also be set directly
in the response header.
This has higher priority than setting of caching time using the directive.
The <header>X-Accel-Expires</header> header field sets caching time of a
response in seconds.
The zero value disables caching for a response.
If a value starts with the <literal>@</literal> prefix, it sets an absolute
time in seconds since Epoch, up to which the response may be cached.
If header does not include the <header>X-Accel-Expires</header> field,
parameters of caching may be set in the header fields
<header>Expires</header> or <header>Cache-Control</header>.
If a header includes the <header>Set-Cookie</header> field, such a
response will not be cached.
Processing of one or more of these response header fields can be disabled
using the <link id="fastcgi_ignore_headers"/> directive.
</para>

</directive>


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

<para>
Sets a string to search for in the error stream of a response
received from a FastCGI server.
If the <value>string</value> is found then it is considered that the FastCGI
server has returned an <link id="fastcgi_next_upstream">invalid response</link>.
This allows handling application errors in nginx, for example:
<example>
location /php {
    fastcgi_pass backend:9000;
    ...
    fastcgi_catch_stderr "PHP Fatal error";
    fastcgi_next_upstream error timeout invalid_header;
}
</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 a 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 a 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 whether the connection with a FastCGI server should be
closed when 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>

<para>
If not disabled, processing of these header fields has the following
effect:
<list type="bullet" compact="no">

<listitem>
<header>X-Accel-Expires</header>, <header>Expires</header>,
<header>Cache-Control</header>, and <header>Set-Cookie</header>
set the parameters of response <link id="fastcgi_cache_valid">caching</link>;
</listitem>

<listitem>
<header>X-Accel-Redirect</header> performs an
<link doc="ngx_http_core_module.xml" id="internal">internal
redirect</link> to the specified URI;
</listitem>

<listitem>
<header>X-Accel-Limit-Rate</header> sets the
<link doc="ngx_http_core_module.xml" id="limit_rate">rate
limit</link> for transmission of a response to a client;
</listitem>

<listitem>
<header>X-Accel-Buffering</header> enables or disables
<link id="fastcgi_buffering">buffering</link> of a response;
</listitem>

<listitem>
<header>X-Accel-Charset</header> sets the desired
<link doc="ngx_http_charset_module.xml" id="charset"/>
of a response.
</listitem>

</list>
</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 300 should be passed to a client or be redirected to nginx for processing
with 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>
<appeared-in>1.1.4</appeared-in>

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

</directive>


<directive name="fastcgi_max_temp_file_size">
<syntax><value>size</value></syntax>
<default>1024m</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
When <link id="fastcgi_buffering">buffering</link> of responses from the FastCGI
server is enabled, and the whole response does not fit into the memory buffers
set by the <link id="fastcgi_buffer_size"/> and <link id="fastcgi_buffers"/>
directives, a part of the response can be saved to a temporary file.
This directive sets the maximum <value>size</value> of a temporary file.
The size of data written to a temporary file at a time is set
by the <link id="fastcgi_temp_file_write_size"/> directive.
</para>

<para>
The zero value disables buffering of responses to temporary files.
</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_403</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 a request to it, 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 a request to it, or reading the response header;</tag-desc>

<tag-name><literal>invalid_header</literal></tag-name>
<tag-desc>a server returned an 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_403</literal></tag-name>
<tag-desc>a server returned a response with the code 403;</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>
One should bear in mind that passing a request to the next server is
only possible if nothing has been sent to a client yet.
That is, if an error or timeout occurs in the middle of the
transferring of a response, fixing this is impossible.
</para>

<para>
The directive also defines what is considered an unsuccessful attempt
of communication with a
<link doc="ngx_http_upstream_module.xml" id="server"/>.
The cases of <literal>error</literal>, <literal>timeout</literal> and
<literal>invalid_header</literal> are always considered unsuccessful attempts,
even if they are not specified in the directive.
The cases of <literal>http_500</literal> and <literal>http_503</literal> are
considered unsuccessful attempts only if they are specified in the directive.
The cases of <literal>http_403</literal> and <literal>http_404</literal>
are never considered unsuccessful attempts.
</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 the address of a FastCGI server.
The address can be specified as a domain name or IP address,
and an optional port:
<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 passing <link id="fastcgi_hide_header">otherwise disabled</link> header
fields from a 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 set only 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_pass_request_body">
<syntax><literal>on</literal> | <literal>off</literal></syntax>
<default>on</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Indicates whether the original request body is passed
to the FastCGI server.
See also the <link id="fastcgi_pass_request_headers"/> directive.
</para>

</directive>


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

<para>
Indicates whether the header fields of the original request are passed
to the FastCGI server.
See also the <link id="fastcgi_pass_request_body"/> directive.
</para>

</directive>


<directive name="fastcgi_send_lowat">
<syntax><value>size</value></syntax>
<default>0</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
If the directive is set to a non-zero value, nginx will try to
minimize the number
of send operations on outgoing connections to a FastCGI server by using either
<c-def>NOTE_LOWAT</c-def> flag of the
<link doc="../events.xml" id="kqueue"/> method,
or the <c-def>SO_SNDLOWAT</c-def> socket option,
with the specified <value>size</value>.
</para>

<para>
This directive is ignored on Linux, Solaris, and Windows.
</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 set only 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, and then the file is renamed.
Starting from version 0.8.9, temporary files and the persistent store
can be put on different file systems.
However, be aware that in this case a file is copied
across two file systems instead of the cheap renaming 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;
    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_file_write_size">
<syntax><value>size</value></syntax>
<default>8k|16k</default>
<context>http</context>
<context>server</context>
<context>location</context>

<para>
Limits the <value>size</value> of data written to a temporary file
at a time, when buffering of responses from the FastCGI server
to temporary files is enabled.
By default, <value>size</value> is limited by two buffers set by the
<link id="fastcgi_buffer_size"/> and <link id="fastcgi_buffers"/> directives.
The maximum size of a temporary file is set by the
<link id="fastcgi_max_temp_file_size"/> directive.
</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
with data received from FastCGI servers.
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 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>