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<modulesynopsis metafile="mod_proxy_fcgi.xml.meta">

<name>mod_proxy_fcgi</name>
<description>FastCGI support module for
<module>mod_proxy</module></description>
<status>Extension</status>
<sourcefile>mod_proxy_fcgi.c</sourcefile>
<identifier>proxy_fcgi_module</identifier>
<compatibility>Available in version 2.3 and later</compatibility>

<summary>
    <p>This module <em>requires</em> the service of <module
    >mod_proxy</module>. It provides support for the
    <a href="http://www.fastcgi.com/">FastCGI</a> protocol.</p>

    <p>Thus, in order to get the ability of handling the <code>FastCGI</code>
    protocol, <module>mod_proxy</module> and
    <module>mod_proxy_fcgi</module> have to be present in the server.</p>

    <p>Unlike <a href="http://httpd.apache.org/mod_fcgid/">mod_fcgid</a>
    and <a href="http://www.fastcgi.com/">mod_fastcgi</a>,
    <module>mod_proxy_fcgi</module> has no provision for starting the
    application process; <program>fcgistarter</program> is provided
    (on some platforms) for that purpose. Alternatively, external launching
    or process management may be available in the FastCGI application
    framework in use.</p>

    <note type="warning"><title>Warning</title>
      <p>Do not enable proxying until you have <a
      href="mod_proxy.html#access">secured your server</a>. Open proxy
      servers are dangerous both to your network and to the Internet at
      large.</p>
    </note>
</summary>

<seealso><program>fcgistarter</program></seealso>
<seealso><module>mod_proxy</module></seealso>

<section id="examples"><title>Examples</title>
    <p>Remember, in order to make the following examples work, you have to
    enable <module>mod_proxy</module> and <module>mod_proxy_fcgi</module>.</p>

    <example><title>Single application instance</title>
    <highlight language="config">
      ProxyPass /myapp/ fcgi://localhost:4000/
      </highlight>
    </example>

    <p>This application should be able to handle multiple concurrent
    connections.  <module>mod_proxy</module> enables connection reuse by
    default, so after a request has been completed the connection will be
    held open by that httpd child process and won't be reused until that
    httpd process routes another request to the application.  If the
    FastCGI application is unable to handle enough concurrent connections
    from httpd, requests can block waiting for the application to close
    an existing connection.  One way to resolve this is to disable connection
    reuse on the <directive>ProxyPass</directive> directive, as shown in
    the following example:</p>

    <example><title>Single application instance, no connection reuse</title>
    <highlight language="config">
      ProxyPass /myapp/ fcgi://localhost:4000/ disablereuse=on
      </highlight>
    </example>

    <p>The balanced gateway needs <module>mod_proxy_balancer</module> and
    at least one load balancer algorithm module, such as
    <module>mod_lbmethod_byrequests</module>, in addition to the proxy
    modules listed above.  <module>mod_lbmethod_byrequests</module> is the
    default, and will be used for this example configuration.</p>

    <example><title>Balanced gateway to multiple application instances</title>
    <highlight language="config">
ProxyPass /myapp/ balancer://myappcluster/
&lt;Proxy balancer://myappcluster/&gt;
    BalancerMember fcgi://localhost:4000
    BalancerMember fcgi://localhost:4001
&lt;/Proxy&gt;
    </highlight>
    </example>
</section>

<section id="env"><title>Environment Variables</title>
    <p>In addition to the configuration directives that control the
    behaviour of <module>mod_proxy</module>, there are a number of
    <dfn>environment variables</dfn> that control the FCGI protocol
    provider:</p>
    <dl>
        <dt>proxy-fcgi-pathinfo</dt>
        <dd>By default <module>mod_proxy_fcgi</module> will neither create
        nor export the <var>PATH_INFO</var> environment variable. This allows
        the backend FCGI server to correctly determine <var>SCRIPT_NAME</var>
        and <var>Script-URI</var> and be compliant with RFC 3875 section 3.3.
        If instead you need <module>mod_proxy_fcgi</module> to generate
        a "best guess" for <var>PATH_INFO</var>, set this env-var.
        This is a workaround for a bug in some FCGI implementations.</dd>
    </dl>
</section>

</modulesynopsis>
