How to use Django with FastCGI, SCGI, or AJP¶

Prerequisite: flup¶

Before you can start using FastCGI with Django, you’ll need to install flup, a Python library for dealing with FastCGI. Version 0.5 or newer should work fine.

Starting your FastCGI server¶

FastCGI operates on a client-server model, and in most cases you’ll be starting the FastCGI process on your own. Your Web server (be it Apache, lighttpd, or otherwise) only contacts your Django-FastCGI process when the server needs a dynamic page to be loaded. Because the daemon is already running with the code in memory, it’s able to serve the response very quickly.

A Web server can connect to a FastCGI server in one of two ways: It can use either a Unix domain socket (a “named pipe” on Win32 systems), or it can use a TCP socket. What you choose is a manner of preference; a TCP socket is usually easier due to permissions issues.

To start your server, first change into the directory of your project (wherever your manage.py is), and then run the runfcgi command:

./manage.py runfcgi [options]

If you specify help as the only option after runfcgi, it’ll display a list of all the available options.

You’ll need to specify either a socket, a protocol or both host and port. Then, when you set up your Web server, you’ll just need to point it at the host/port or socket you specified when starting the FastCGI server. See the examples, below.

./manage.py runfcgi protocol=scgi

./manage.py runfcgi method=threaded host=127.0.0.1 port=3033

./manage.py runfcgi method=prefork socket=/home/user/mysite.sock pidfile=django.pid

./manage.py runfcgi daemonize=false socket=/tmp/mysite.sock maxrequests=1

kill `cat $PIDFILE`

#!/bin/bash

# Replace these three settings.
PROJDIR="/home/user/myproject"
PIDFILE="$PROJDIR/mysite.pid"
SOCKET="$PROJDIR/mysite.sock"

cd $PROJDIR
if [ -f $PIDFILE ]; then
    kill `cat -- $PIDFILE`
    rm -f -- $PIDFILE
fi

exec /usr/bin/env - \
  PYTHONPATH="../python:.." \
  ./manage.py runfcgi socket=$SOCKET pidfile=$PIDFILE

Apache setup¶

To use Django with Apache and FastCGI, you’ll need Apache installed and configured, with mod_fastcgi installed and enabled. Consult the Apache documentation for instructions.

Once you’ve got that set up, point Apache at your Django FastCGI instance by editing the httpd.conf (Apache configuration) file. You’ll need to do two things:

• Use the FastCGIExternalServer directive to specify the location of your FastCGI server.
• Use mod_rewrite to point URLs at FastCGI as appropriate.

# Connect to FastCGI via a socket / named pipe.
FastCGIExternalServer /home/user/public_html/mysite.fcgi -socket /home/user/mysite.sock

# Connect to FastCGI via a TCP host/port.
FastCGIExternalServer /home/user/public_html/mysite.fcgi -host 127.0.0.1:3033

<VirtualHost 12.34.56.78>
  ServerName example.com
  DocumentRoot /home/user/public_html
  Alias /media /home/user/python/django/contrib/admin/media
  RewriteEngine On
  RewriteRule ^/(media.*)$ /$1 [QSA,L,PT]
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteRule ^/(.*)$ /mysite.fcgi/$1 [QSA,L]
</VirtualHost>

lighttpd setup¶

lighttpd is a lightweight Web server commonly used for serving static files. It supports FastCGI natively and, thus, is a good choice for serving both static and dynamic pages, if your site doesn’t have any Apache-specific needs.

Make sure mod_fastcgi is in your modules list, somewhere after mod_rewrite and mod_access, but not after mod_accesslog. You’ll probably want mod_alias as well, for serving admin media.

Add the following to your lighttpd config file:

server.document-root = "/home/user/public_html"
fastcgi.server = (
    "/mysite.fcgi" => (
        "main" => (
            # Use host / port instead of socket for TCP fastcgi
            # "host" => "127.0.0.1",
            # "port" => 3033,
            "socket" => "/home/user/mysite.sock",
            "check-local" => "disable",
        )
    ),
)
alias.url = (
    "/media" => "/home/user/django/contrib/admin/media/",
)

url.rewrite-once = (
    "^(/media.*)$" => "$1",
    "^/favicon\.ico$" => "/media/favicon.ico",
    "^(/.*)$" => "/mysite.fcgi$1",
)

# If the hostname is 'www.example1.com'...
$HTTP["host"] == "www.example1.com" {
    server.document-root = "/foo/site1"
    fastcgi.server = (
       ...
    )
    ...
}

# If the hostname is 'www.example2.com'...
$HTTP["host"] == "www.example2.com" {
    server.document-root = "/foo/site2"
    fastcgi.server = (
       ...
    )
    ...
}

Cherokee setup¶

Cherokee is a very fast, flexible and easy to configure Web Server. It supports the widespread technologies nowadays: FastCGI, SCGI, PHP, CGI, SSI, TLS and SSL encrypted connections, Virtual hosts, Authentication, on the fly encoding, Load Balancing, Apache compatible log files, Data Base Balancer, Reverse HTTP Proxy and much more.

The Cherokee project provides a documentation to setting up Django with Cherokee.

Running Django on a shared-hosting provider with Apache¶

Many shared-hosting providers don’t allow you to run your own server daemons or edit the httpd.conf file. In these cases, it’s still possible to run Django using Web server-spawned processes.

In your Web root directory, add this to a file named .htaccess:

AddHandler fastcgi-script .fcgi
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ mysite.fcgi/$1 [QSA,L]

Then, create a small script that tells Apache how to spawn your FastCGI program. Create a file mysite.fcgi and place it in your Web directory, and be sure to make it executable:

#!/usr/bin/python
import sys, os

# Add a custom Python path.
sys.path.insert(0, "/home/user/python")

# Switch to the directory of your project. (Optional.)
# os.chdir("/home/user/myproject")

# Set the DJANGO_SETTINGS_MODULE environment variable.
os.environ['DJANGO_SETTINGS_MODULE'] = "myproject.settings"

from django.core.servers.fastcgi import runfastcgi
runfastcgi(method="threaded", daemonize="false")

This works if your server uses mod_fastcgi. If, on the other hand, you are using mod_fcgid the setup is mostly the same except for a slight change in the .htaccess file. Instead of adding a fastcgi-script handler, you have to add a fcgid-handler:

AddHandler fcgid-script .fcgi
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ mysite.fcgi/$1 [QSA,L]

touch mysite.fcgi

Serving admin media files¶

Regardless of the server and configuration you eventually decide to use, you will also need to give some thought to how to serve the admin media files. The advice given in the mod_wsgi documentation is also applicable in the setups detailed above.

Forcing the URL prefix to a particular value¶

Because many of these fastcgi-based solutions require rewriting the URL at some point inside the Web server, the path information that Django sees may not resemble the original URL that was passed in. This is a problem if the Django application is being served from under a particular prefix and you want your URLs from the {% url %} tag to look like the prefix, rather than the rewritten version, which might contain, for example, mysite.fcgi.

Django makes a good attempt to work out what the real script name prefix should be. In particular, if the Web server sets the SCRIPT_URL (specific to Apache’s mod_rewrite), or REDIRECT_URL (set by a few servers, including Apache + mod_rewrite in some situations), Django will work out the original prefix automatically.

In the cases where Django cannot work out the prefix correctly and where you want the original value to be used in URLs, you can set the FORCE_SCRIPT_NAME setting in your main settings file. This sets the script name uniformly for every URL served via that settings file. Thus you’ll need to use different settings files if you want different sets of URLs to have different script names in this case, but that is a rare situation.

As an example of how to use it, if your Django configuration is serving all of the URLs under '/' and you wanted to use this setting, you would set FORCE_SCRIPT_NAME = '' in your settings file.