==========================================
How to use Django with Apache and mod_wsgi
==========================================

Deploying Django with Apache_ and `mod_wsgi`_ is a tried and tested way to get
Django into production.

.. _Apache: http://httpd.apache.org/
.. _mod_wsgi: http://www.modwsgi.org/

mod_wsgi is an Apache module which can host any Python WSGI_ application,
including Django. Django will work with any version of Apache which supports
mod_wsgi.

.. _WSGI: http://www.wsgi.org

The `official mod_wsgi documentation`_ is fantastic; it's your source for all
the details about how to use mod_wsgi. You'll probably want to start with the
`installation and configuration documentation`_.

.. _official mod_wsgi documentation: http://modwsgi.readthedocs.org/
.. _installation and configuration documentation: http://modwsgi.readthedocs.org/en/develop/installation.html

Basic configuration
===================

Once you've got mod_wsgi installed and activated, edit your Apache server's
``httpd.conf`` file and add the following. If you are using a version of Apache
older than 2.4, replace ``Require all granted`` with ``Allow from all`` and
also add the line ``Order deny,allow`` above it.

.. code-block:: apache

    WSGIScriptAlias / /path/to/mysite.com/mysite/wsgi.py
    WSGIPythonPath /path/to/mysite.com

    <Directory /path/to/mysite.com/mysite>
    <Files wsgi.py>
    Require all granted
    </Files>
    </Directory>

The first bit in the ``WSGIScriptAlias`` line is the base URL path you want to
serve your application at (``/`` indicates the root url), and the second is the
location of a "WSGI file" -- see below -- on your system, usually inside of
your project package (``mysite`` in this example). This tells Apache to serve
any request below the given URL using the WSGI application defined in that
file.

The ``WSGIPythonPath`` line ensures that your project package is available for
import on the Python path; in other words, that ``import mysite`` works.

The ``<Directory>`` piece just ensures that Apache can access your
:file:`wsgi.py` file.

Next we'll need to ensure this :file:`wsgi.py` with a WSGI application object
exists. As of Django version 1.4, :djadmin:`startproject` will have created one
for you; otherwise, you'll need to create it. See the :doc:`WSGI overview
documentation</howto/deployment/wsgi/index>` for the default contents you
should put in this file, and what else you can add to it.

.. warning::

    If multiple Django sites are run in a single mod_wsgi process, all of them
    will use the settings of whichever one happens to run first. This can be
    solved by changing::

        os.environ.setdefault("DJANGO_SETTINGS_MODULE", "{{ project_name }}.settings")

    in ``wsgi.py``, to::

        os.environ["DJANGO_SETTINGS_MODULE"] = "{{ project_name }}.settings"

    or by :ref:`using mod_wsgi daemon mode<daemon-mode>` and ensuring that each
    site runs in its own daemon process.

Using a virtualenv
==================

If you install your project's Python dependencies inside a `virtualenv`_,
you'll need to add the path to this virtualenv's ``site-packages`` directory to
your Python path as well. To do this, add an additional path to your
``WSGIPythonPath`` directive, with multiple paths separated by a colon (``:``)
if using a UNIX-like system, or a semicolon (``;``) if using Windows. If any
part of a directory path contains a space character, the complete argument
string to ``WSGIPythonPath`` must be quoted:

.. code-block:: apache

    WSGIPythonPath /path/to/mysite.com:/path/to/your/venv/lib/python3.X/site-packages

Make sure you give the correct path to your virtualenv, and replace
``python3.X`` with the correct Python version (e.g. ``python3.4``).

.. _virtualenv: http://www.virtualenv.org

.. _daemon-mode:

Using mod_wsgi daemon mode
==========================

"Daemon mode" is the recommended mode for running mod_wsgi (on non-Windows
platforms). To create the required daemon process group and delegate the
Django instance to run in it, you will need to add appropriate
``WSGIDaemonProcess`` and ``WSGIProcessGroup`` directives. A further change
required to the above configuration if you use daemon mode is that you can't
use ``WSGIPythonPath``; instead you should use the ``python-path`` option to
``WSGIDaemonProcess``, for example:

.. code-block:: apache

    WSGIDaemonProcess example.com python-path=/path/to/mysite.com:/path/to/venv/lib/python2.7/site-packages
    WSGIProcessGroup example.com

If you want to serve your project in a subdirectory
(``http://example.com/mysite`` in this example), you can add ``WSGIScriptAlias``
to the configuration above:

.. code-block:: apache

    WSGIScriptAlias /mysite /path/to/mysite.com/mysite/wsgi.py process-group=example.com

See the official mod_wsgi documentation for `details on setting up daemon
mode`_.

.. _details on setting up daemon mode: http://code.google.com/p/modwsgi/wiki/QuickConfigurationGuide#Delegation_To_Daemon_Process

Apache environment variables
============================

If you want to specify a different Django settings file or additional variables
for your Django application via the Apache configuration, you would do it like
this:

.. code-block:: apache

    SetEnv DB_USER dbusername
    SetEnv DJANGO_SETTINGS_MODULE mysite.alternate-settings

The ``SetEnv`` directive creates Apache environment variables instead of OS
environment variables, so you will need to replace the default ``wsgi.py`` file
with::

    import os

    from django.core.wsgi import get_wsgi_application

    # A tuple of Apache environment variables to pass through to Django.
    env_variables_to_pass = ('DB_USER', )

    def application(environ, start_response):
        """
        Wrapper for the WSGI application that passes environment variables.
        """
        os.environ['DJANGO_SETTINGS_MODULE'] = environ.get('DJANGO_SETTINGS_MODULE', 'mysite.settings')
        for var in env_variables_to_pass:
            os.environ[var] = environ.get(var, '')
        return get_wsgi_application()(environ, start_response)

Now you can specify a new settings file in Apache using the
``SetEnv DJANGO_SETTINGS_MODULE ...`` line, and if that setting isn't
specified, it uses ``'mysite.settings'`` as a default. You'll want to change
``mysite.settings`` to reference your own ``settings.py`` module.

Additionally, you can use the ``env_variables_to_pass`` tuple to specify any
other Apache environment variables, such as database login credentials, that
should be passed along to the Django application as OS environment variables.

.. _serving-files:

Serving files
=============

Django doesn't serve files itself; it leaves that job to whichever Web
server you choose.

We recommend using a separate Web server -- i.e., one that's not also running
Django -- for serving media. Here are some good choices:

* Nginx_
* A stripped-down version of Apache_

If, however, you have no option but to serve media files on the same Apache
``VirtualHost`` as Django, you can set up Apache to serve some URLs as
static media, and others using the mod_wsgi interface to Django.

This example sets up Django at the site root, but explicitly serves
``robots.txt``, ``favicon.ico``, any CSS file, and anything in the
``/static/`` and ``/media/`` URL space as a static file. All other URLs
will be served using mod_wsgi:

.. code-block:: apache

    Alias /robots.txt /path/to/mysite.com/static/robots.txt
    Alias /favicon.ico /path/to/mysite.com/static/favicon.ico

    Alias /media/ /path/to/mysite.com/media/
    Alias /static/ /path/to/mysite.com/static/

    <Directory /path/to/mysite.com/static>
    Require all granted
    </Directory>

    <Directory /path/to/mysite.com/media>
    Require all granted
    </Directory>

    WSGIScriptAlias / /path/to/mysite.com/mysite/wsgi.py

    <Directory /path/to/mysite.com/mysite>
    <Files wsgi.py>
    Require all granted
    </Files>
    </Directory>

If you are using a version of Apache older than 2.4, replace
``Require all granted`` with ``Allow from all`` and also add the line
``Order deny,allow`` above it.

.. _Nginx: http://wiki.nginx.org/Main
.. _Apache: http://httpd.apache.org/

.. More details on configuring a mod_wsgi site to serve static files can be found
.. in the mod_wsgi documentation on `hosting static files`_.

.. _hosting static files: http://code.google.com/p/modwsgi/wiki/ConfigurationGuidelines#Hosting_Of_Static_Files

.. _serving-the-admin-files:

Serving the admin files
=======================

When :mod:`django.contrib.staticfiles` is in :setting:`INSTALLED_APPS`, the
Django development server automatically serves the static files of the
admin app (and any other installed apps). This is however not the case when you
use any other server arrangement. You're responsible for setting up Apache, or
whichever Web server you're using, to serve the admin files.

The admin files live in (:file:`django/contrib/admin/static/admin`) of the
Django distribution.

We **strongly** recommend using :mod:`django.contrib.staticfiles` to handle the
admin files (along with a Web server as outlined in the previous section; this
means using the :djadmin:`collectstatic` management command to collect the
static files in :setting:`STATIC_ROOT`, and then configuring your Web server to
serve :setting:`STATIC_ROOT` at :setting:`STATIC_URL`), but here are three
other approaches:

1. Create a symbolic link to the admin static files from within your
   document root (this may require ``+FollowSymLinks`` in your Apache
   configuration).

2. Use an ``Alias`` directive, as demonstrated above, to alias the appropriate
   URL (probably :setting:`STATIC_URL` + ``admin/``) to the actual location of
   the admin files.

3. Copy the admin static files so that they live within your Apache
   document root.

Authenticating against Django's user database from Apache
=========================================================

Django provides a handler to allow Apache to authenticate users directly
against Django's authentication backends. See the :doc:`mod_wsgi authentication
documentation </howto/deployment/wsgi/apache-auth>`.

If you get a UnicodeEncodeError
===============================

If you're taking advantage of the internationalization features of Django (see
:doc:`/topics/i18n/index`) and you intend to allow users to upload files, you must
ensure that the environment used to start Apache is configured to accept
non-ASCII file names. If your environment is not correctly configured, you
will trigger ``UnicodeEncodeError`` exceptions when calling functions like
the ones in :mod:`os.path` on filenames that contain non-ASCII characters.

To avoid these problems, the environment used to start Apache should contain
settings analogous to the following::

    export LANG='en_US.UTF-8'
    export LC_ALL='en_US.UTF-8'

Consult the documentation for your operating system for the appropriate syntax
and location to put these configuration items; ``/etc/apache2/envvars`` is a
common location on Unix platforms. Once you have added these statements
to your environment, restart Apache.