Apache Module mod_proxy_fcgi

Summary

This module requires the service of mod_proxy. It provides support for the FastCGI protocol.

Thus, in order to get the ability of handling the FastCGI protocol, mod_proxy and mod_proxy_fcgi have to be present in the server.

Unlike mod_fcgid and mod_fastcgi, mod_proxy_fcgi has no provision for starting the application process; fcgistarter is provided (on some platforms) for that purpose. Alternatively, external launching or process management may be available in the FastCGI application framework in use.

Examples

Remember, in order to make the following examples work, you have to enable mod_proxy and mod_proxy_fcgi.

ProxyPass "/myapp/" "fcgi://localhost:4000/"

mod_proxy_fcgi disables connection reuse by default, so after a request has been completed the connection will NOT be held open by that httpd child process and won't be reused. If the FastCGI application is able to handle concurrent connections from httpd, you can opt-in to connection reuse as shown in the following example:

ProxyPass "/myapp/" "fcgi://localhost:4000/" enablereuse=on

The following example passes the request URI as a filesystem path for the PHP-FPM daemon to run. The request URL is implicitly added to the 2nd parameter. The hostname and port following fcgi:// are where PHP-FPM is listening. Connection pooling/reuse is enabled.

ProxyPassMatch "^/myapp/.*\.php(/.*)?$" "fcgi://localhost:9000/var/www/" enablereuse=on

The following example passes the request URI as a filesystem path for the PHP-FPM daemon to run. In this case, PHP-FPM is listening on a unix domain socket (UDS). Requires 2.4.9 or later. With this syntax, the hostname and optional port following fcgi:// are ignored.

ProxyPassMatch "^/(.*\.php(/.*)?)$" "unix:/var/run/php5-fpm.sock|fcgi://localhost/var/www/"

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

ProxyPass "/myapp/" "balancer://myappcluster/"
<Proxy "balancer://myappcluster/">
    BalancerMember "fcgi://localhost:4000"
    BalancerMember "fcgi://localhost:4001"
</Proxy>

You can also force a request to be handled as a reverse-proxy request, by creating a suitable Handler pass-through. The example configuration below will pass all requests for PHP scripts to the specified FastCGI server using reverse proxy. This feature is available in Apache HTTP Server 2.4.10 and later. For performance reasons, you will want to define a worker representing the same fcgi:// backend. The benefit of this form is that it allows the normal mapping of URI to filename to occur in the server, and the local filesystem result is passed to the backend. When FastCGI is configured this way, the server can calculate the most accurate PATH_INFO.

<FilesMatch "\.php$">
    # Note: The only part that varies is /path/to/app.sock
    SetHandler  "proxy:unix:/path/to/app.sock|fcgi://localhost/"
</FilesMatch>

# Define a matching worker.
# The part that is matched to the SetHandler is the part that
# follows the pipe. If you need to distinguish, "localhost; can
# be anything unique.
<Proxy "fcgi://localhost/" enablereuse=on max=10>
</Proxy>

<FilesMatch ...>
    SetHandler  "proxy:fcgi://localhost:9000"
</FilesMatch>

<FilesMatch ...>
    SetHandler  "proxy:balancer://myappcluster/"
</FilesMatch>

Environment Variables

In addition to the configuration directives that control the behaviour of mod_proxy, there are a number of environment variables that control the FCGI protocol provider:

proxy-fcgi-pathinfo

When configured via ProxyPass or ProxyPassMatch, mod_proxy_fcgi will not set the PATH_INFO environment variable. This allows the backend FCGI server to correctly determine SCRIPT_NAME and Script-URI and be compliant with RFC 3875 section 3.3. If instead you need mod_proxy_fcgi to generate a "best guess" for PATH_INFO, set this env-var. This is a workaround for a bug in some FCGI implementations. This variable can be set to multiple values to tweak at how the best guess is chosen (In 2.4.11 and later only):

first-dot

PATH_INFO is split from the slash following the first "." in the URL.

last-dot

PATH_INFO is split from the slash following the last "." in the URL.

full

PATH_INFO is calculated by an attempt to map the URL to the local filesystem.

unescape

PATH_INFO is the path component of the URL, unescaped / decoded.

any other value

PATH_INFO is the same as the path component of the URL. Originally, this was the only proxy-fcgi-pathinfo option.

ProxyFCGIBackendType FPM|GENERIC

ProxyFCGIBackendType FPM

ProxyFCGISetEnvIf conditional-expression [!]environment-variable-name [value-expression]

# A basic, unconditional override
ProxyFCGISetEnvIf "true" PATH_INFO "/example"

# Use an environment variable in the value
ProxyFCGISetEnvIf "true" PATH_INFO "%{reqenv:SCRIPT_NAME}"

# Use captures in the conditions and backreferences in the replacement
ProxyFCGISetEnvIf "reqenv('PATH_TRANSLATED') =~ m|(/.*prefix)(\d+)(.*)|" PATH_TRANSLATED "$1$3"

ProxyFCGISetEnvIf true !VARIABLE

ProxyFCGISetEnvIf true VARIABLE