PHP FastCGI Example

This example is for newer PHP (>= 5.3.3) using the included PHP FPM (FastCGI Process Manager).

This guide assume PHP FPM already installed and configured either using tcp port (127.0.0.1:9000) or unix socket (/var/run/php-fpm.sock).

There are many guide about configuring NGINX with PHP FPM, but many of them are incomplete (don’t handle PATH_INFO correctly) or contain security issues (don’t check whether the script is indeed php file).

FastCGI Params

First thing, I recommend keeping all your typical FCGI settings in a single file and importing them.

For example on debian and ubuntu by default there is /etc/nginx/fastcgi_params file that should look like this:

fastcgi_param   QUERY_STRING            $query_string;
fastcgi_param   REQUEST_METHOD          $request_method;
fastcgi_param   CONTENT_TYPE            $content_type;
fastcgi_param   CONTENT_LENGTH          $content_length;

fastcgi_param   SCRIPT_FILENAME         $document_root$fastcgi_script_name;
fastcgi_param   SCRIPT_NAME             $fastcgi_script_name;
fastcgi_param   PATH_INFO               $fastcgi_path_info;
fastcgi_param   PATH_TRANSLATED         $document_root$fastcgi_path_info;
fastcgi_param   REQUEST_URI             $request_uri;
fastcgi_param   DOCUMENT_URI            $document_uri;
fastcgi_param   DOCUMENT_ROOT           $document_root;
fastcgi_param   SERVER_PROTOCOL         $server_protocol;

fastcgi_param   GATEWAY_INTERFACE       CGI/1.1;
fastcgi_param   SERVER_SOFTWARE         nginx/$nginx_version;

fastcgi_param   REMOTE_ADDR             $remote_addr;
fastcgi_param   REMOTE_PORT             $remote_port;
fastcgi_param   SERVER_ADDR             $server_addr;
fastcgi_param   SERVER_PORT             $server_port;
fastcgi_param   SERVER_NAME             $server_name;

fastcgi_param   HTTPS                   $https;

# PHP only, required if PHP was built with --enable-force-cgi-redirect
fastcgi_param   REDIRECT_STATUS         200;

Please note if you’re using Ubuntu Precise (12.04), I change SCRIPT_FILENAME and add PATH_INFO params.

Connecting NGINX to PHP FPM

Now we must tell NGINX to proxy requests to PHP FPM via the FCGI protocol:

location ~ [^/]\.php(/|$) {
    fastcgi_split_path_info ^(.+?\.php)(/.*)$;
    if (!-f $document_root$fastcgi_script_name) {
        return 404;
    }

    # Mitigate https://httpoxy.org/ vulnerabilities
    fastcgi_param HTTP_PROXY "";

    fastcgi_pass 127.0.0.1:9000;
    fastcgi_index index.php;

    # include the fastcgi_param setting
    include fastcgi_params;

    # SCRIPT_FILENAME parameter is used for PHP FPM determining
    #  the script name. If it is not set in fastcgi_params file,
    # i.e. /etc/nginx/fastcgi_params or in the parent contexts,
    # please comment off following line:
    # fastcgi_param  SCRIPT_FILENAME   $document_root$fastcgi_script_name;
}

If you’re using unix socket change fastcgi_pass to:

fastcgi_pass unix:/var/run/php-fpm.sock;

Restart NGINX.

Testing

Create test.php on NGINX document root containing just:

<?php var_export($_SERVER)?>

In the browser try to request: # /test.php # /test.php/ # /test.php/foo # /test.php/foo/bar.php # /test.php/foo/bar.php?v=1

Pay attention to the value of REQUEST_URI, SCRIPT_FILENAME, SCRIPT_NAME, PATH_INFO and PHP_SELF.

Here’s the correct output for http://lemp.test/test.php/foo/bar.php?v=1

array (
  'USER' => 'www-data',
  'HOME' => '/var/www',
  'FCGI_ROLE' => 'RESPONDER',
  'QUERY_STRING' => 'v=1',
  'REQUEST_METHOD' => 'GET',
  'CONTENT_TYPE' => '',
  'CONTENT_LENGTH' => '',
  'SCRIPT_FILENAME' => '/var/www/test.php',
  'SCRIPT_NAME' => '/test.php',
  'PATH_INFO' => '/foo/bar.php',
  'REQUEST_URI' => '/test.php/foo/bar.php?v=1',
  'DOCUMENT_URI' => '/test.php/foo/bar.php',
  'DOCUMENT_ROOT' => '/var/www',
  'SERVER_PROTOCOL' => 'HTTP/1.1',
  'GATEWAY_INTERFACE' => 'CGI/1.1',
  'SERVER_SOFTWARE' => 'nginx/1.4.0',
  'REMOTE_ADDR' => '192.168.56.1',
  'REMOTE_PORT' => '44644',
  'SERVER_ADDR' => '192.168.56.3',
  'SERVER_PORT' => '80',
  'SERVER_NAME' => '',
  'HTTPS' => '',
  'REDIRECT_STATUS' => '200',
  'HTTP_HOST' => 'lemp.test',
  'HTTP_USER_AGENT' => 'Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:20.0) Gecko/20100101 Firefox/20.0',
  'HTTP_ACCEPT' => 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
  'HTTP_ACCEPT_LANGUAGE' => 'en-US,en;q=0.5',
  'HTTP_ACCEPT_ENCODING' => 'gzip, deflate',
  'HTTP_CONNECTION' => 'keep-alive',
  'PHP_SELF' => '/test.php/foo/bar.php',
  'REQUEST_TIME' => 1367829847,
)

Notes

  1. The location regex capable to handle PATH_INFO and properly check that the extension indeed .php (not .phps) whether there is PATH_INFO or not.

  2. The fastcgi_split_path_info regex capable to correctly handle request like /test.php/foo/blah.php or /test.php/.

  3. The if lets NGINX check whether the *.php does indeed exist to prevent NGINX to feeding PHP FPM non php script file (like uploaded image).

    Some guides recommend to use try_files instead of if, if you do that, beware of NGINX bug #321. I personally think if is more appropriate for this, even If Is Evil agree this is one of the 100% safe thing to use if with.

  4. The SCRIPT_FILENAME parameter is required as it is passed to PHP FPM to determine the script name.

    In the builds of NGINX for a lot of Linux distributions, this parameter has been added in fastcgi_params file, i.e. /etc/nginx/fastcgi_params``so the users could import all the CGI params via the ``include directive, i.e. include fastcgi_params . But for some distributions, such as CentOS, this parameter does not exist in fastcgi_params file.

    If this parameter is not set, PHP FPM responses 200 OK with empty content, and there is no error or warning. For more informaton about the CGI params, please refer to nginx beginners guide, $_SERVER in PHP and RFC3875.

  5. If you see a blank page in browser, please check if SCRIPT_FILENAME parameter is set.

  6. This guide run fine on php.ini with cgi.fix_pathinfo = 1 (the default).

    Some guide insist to change it to cgi.fix_pathinfo = 0 but doing that make PHP_SELF variable broken (not equal to DOCUMENT_URI).