Ticket #14514: static-files.patch

=====================
Managing static files
=====================

.. currentmodule:: django.contrib.staticfiles

.. versionadded:: 1.3

Django developers mostly concern themselves with the dynamic parts of web
applications -- the views and templates that render anew for each request. But
web applications have other parts: the static media files (images, CSS,
Javascript, etc.) that are needed to render a complete web page.

For small projects, this isn't a big deal, because you can just keep the media
somewhere your web server can find it. However, in bigger projects -- especially
those comprised of multiple apps -- dealing with the multiple sets of static
files provided by each application starts to get tricky.

That's what ``django.contrib.staticfiles`` is for: it collects media from each
of your applications (and any other places you specify) into a single location
that can easily be served in production.

.. note::

    If you've used the `django-staticfiles`_ third-party app before, then
    ``django.contrib.staticfiles`` will look very familiar. That's because
    they're essentially the same code: ``django.contrib.staticfiles`` started
    its life as `django-staticfiles`_ and was merged into Django 1.3.
    
    If you're upgrading from ``django-staticfiles``, please see `Upgrading from
    django-staticfiles`_, below, for a few minor changes you'll need to make.

.. _django-staticfiles: http://pypi.python.org/pypi/django-staticfiles/

Using ``django.contrib.staticfiles``
====================================

Here's the basic usage in a nutshell:

    1. Put your media somewhere that staticfiles will find it..

       Most of the time this place will be in a ``static`` directory within your
       application, but it could also be a specific directory you've put into
       your settings file. See the the documentation for the
       :setting:`STATICFILES_DIRS` and :setting:`STATICFILES_FINDERS` settings
       for details on where you can put media.

    2. Add some ``staticfiles``-related settings to your settings file.

       First, you'll need to make sure that ``django.contrib.staticfiles`` is in
       your :setting:`INSTALLED_APPS`.

       Next, you'll need to edit :setting:`STATICFILES_ROOT` to point to where
       you'd like your static media stored. For example::

            STATICFILES_ROOT = "/home/jacob/projects/mysite.com/static_media"

       You may also want to set the :setting:`STATICFILES_URL` setting at this
       time, though the default value (of ``/static/``) is perfect for local
       development.

       There are a number of other options available that let you control *how*
       media is stored, where ``staticfiles`` searches for files, and how files
       will be served; see :ref:`the staticfiles settings reference
       <staticfiles-settings>` for details.

    3. Run the :djadmin:`collectstatic` management command::

            ./manage.py collectstatic

       This'll churn through your static file storage and move them into the
       directory given by :setting:`STATICFILES_ROOT`.

    4. Deploy that media.

       If you're using the built-in development server, you can quickly
       serve static media locally by adding::

            from django.contrib.staticfiles.urls import staticfiles_urlpatterns
            urlpatterns += staticfiles_urlpatterns()

       to the bottom of your URLconf. See :ref:`staticfiles-development` for
       details.

       When it comes time to deploy to production, :ref:`staticfiles-production`
       covers some common deployment strategies for static files.

       However you choose to deploy those files, you'll probably need to refer
       to them in your templates. The easiest method is to use the included
       context processor which will allow template code like:

          .. code-block:: html+django

               <img src="{{ STATICFILES_URL }}images/hi.jpg />

       See :ref:`staticfiles-in-templates` for more details, including an
       alternate method (using a template tag).

Those are the basics. For more details on common configuration options, read on;
for a detailed reference of the settings, commands, and other bits included with
the framework see :doc:`the staticfiles reference </ref/contrib/staticfiles>`.

.. _staticfiles-in-templates:

Referring to static files in templates
======================================

At some point, you'll probably need to link to static files in your templates.
You could, of course, simply hardcode the path to you assets in the templates:

.. code-block:: html

    <img src="http://media.example.com/static/myimage.jpg" />

Of course, there are some serious problems with this: it doesn't work well in
development, and it makes it *very* hard to change where you've deployed your
media. If, for example, you wanted to switch to using a content delivery network
(CDN), then you'd need to change more or less every single template.

A far better way is to use the value of the :setting:`STATICFILES_URL` setting
directly in your templates. This means that a switch of media servers only
requires changing that single value. Much better!

``staticfiles`` inludes two built-in ways of getting at this setting in your
templates: a context processor and a template tag.

With a context processor
------------------------

The included context processor is the easy way. Simply make sure
``'django.contrib.staticfiles.context_processors.staticfiles'`` is in your
:setting:`TEMPLATE_CONTEXT_PROCESSORS`. It's there by default, and if you're
editing that setting by hand it should look something like::

    TEMPLATE_CONTEXT_PROCESSORS = (
        'django.core.context_processors.debug',
        'django.core.context_processors.i18n',
        'django.contrib.auth.context_processors.auth',
        'django.contrib.messages.context_processors.messages',
        'django.contrib.staticfiles.context_processors.staticfiles',
    )

Once that's done, you can refer to :setting:`STATICFILES_URL` in your templates:

.. code-block:: html+django

     <img src="{{ STATICFILES_URL }}images/hi.jpg />

If ``{{ STATICFILES_URL }}`` isn't working in your template, you're probably not
using :class:`~django.template.RequestContext` when rendering the template.

As a brief refresher, context processors add variables into the contexts of
every template. However, context processors require that you use
:class:`~django.template.RequestContext` when rendering templates. This happens
automatically if you're using a :doc:`generic view </ref/class-based-views>`,
but in views written by hand you'll need to explicitally use ``RequestContext``
To see how that works, and to read more details, check out
:ref:`subclassing-context-requestcontext`.

With a template tag
-------------------

The second option is the :ttag:`get_staticfiles_prefix` template tag. You can
use this if you're not using :class:`~django.template.RequestContext`, or if you
need more control over exactly where and how :setting:`STATICFILES_URL` is
injected into the template. Here's an example:

.. code-block:: html+django

    {% load staticfiles %}
    <img src="{% get_staticfiles_prefix %}images/hi.jpg" />

There's also a second form you can use to avoid extra processing if you need the
value multiple times:

.. code-block:: html+django

    {% load staticfiles %}
    {% get_staticfiles_prefix as STATIC_PREFIX %}

    <img src="{{ STATIC_PREFIX }}images/hi.jpg" />
    <img src="{{ STATIC_PREFIX }}images/hi2.jpg" />

.. _staticfiles-development:

Serving static files in development
===================================

The static files tools are mostly designed to help with getting static media
successfully deployed into production. This usually means a separate, dedicated
media server, which is a lot of overhead to mess with when developing locally.
Thus, the ``staticfiles`` app ships with a quick and dirty helper view that you
can use to serve media locally in development.

To enable this view, you'll add a couple of lines to your URLconf. The first
line goes at the top of the file, and the last line at the bottom::

    from django.contrib.staticfiles.urls import staticfiles_urlpatterns

    # ... the rest of your URLconf goes here ...

    urlpatterns += staticfiles_urlpatterns()

This will inspect your :setting:`STATICFILES_URL` and
:setting:`STATICFILES_ROOT` settings and wire up the view to serve static media
accordingly. Remember to run :djadmin:`collectstatic` when your media changes;
the view only serves static files that have been collected.

.. warning::

    This will only work if :setting:`DEBUG` is ``True``.

    That's because this view is **grossly inefficient** and probably
    **insecure**. This is only intended for local development, and should
    **never be used in production**.

For a few more details, including an alternate method of enabling this view,
see :ref:`staticfiles-development-view`.

.. _staticfiles-production:

Serving static files in production
==================================

The basic outline of putting static files into production a simple: run the
:djadmin:`collectstatic` command when static media changes, then arrange for the
collected media directory (:setting:`STATICFILES_ROOT`) to be moved to the media
server and served.

Of course, as with all deployment tasks, the devil's in the details. Every
production setup will be a bit different, so you'll need to adapt the basic
outline to fit your needs. Below are a few common patterns that might help.

Serving the app and your static files from the same server
----------------------------------------------------------

If you want to serve your media from the same server that's already serving your
app, the basic outline gets modified to look something like:

    * Push your code up to the deployment server.
    * On the server, run :djadmin:`collectmedia` to move all the media into
      :setting:`STATICFILES_ROOT`.
    * Point your web server at :setting:`STATICFILES_ROOT`. For example, here's
      of :ref:`how to do this under Apache and mod_wsgi <serving-media-files>`.

You'll probably want to automate this process, especially if you've got multiple
web servers. There's any number of ways to do this automation, but one option
that many Django developers enjoy is `Fabric`__.

__ http://fabfile.org/

Below, and in the following sections, we'll show off a few example fabfiles
(i.e. Fabric scripts) that automate these media deployment options. The syntax
of a fabfile is fairly streightforward but won't be covered here; consult `Fabric's documentation`__, for a complete explanation of the syntax..

__ http://docs.fabfile.org/

So, a fabfile to deploy media to a couple of web servers might look something
like::

    from fabric.api import *

    # Hosts to deploy onto
    env.hosts = ['www1.example.com', 'www2.example.com']

    # Where your project code lives on the server
    env.project_root = '/home/www/myproject'

    def deploy_static():
        with cd(env.project_root):
            run('./manage.py collectstatic')

Serving static files from a dedicated media server
--------------------------------------------------

Most larger Django apps use a separate Web server -- i.e., one that's not also
running Django -- for serving media. This server often runs a different type of
web server -- faster but less full-featured. Some good choices are:

    * lighttpd_
    * Nginx_
    * TUX_
    * Cherokee_
    * A stripped-down version of Apache_

.. _lighttpd: http://www.lighttpd.net/
.. _Nginx: http://wiki.nginx.org/Main
.. _TUX: http://en.wikipedia.org/wiki/TUX_web_server
.. _Apache: http://httpd.apache.org/
.. _Cherokee: http://www.cherokee-project.com/

Configuring these servers is out of scope of this document; check each server's
respective documentation for instructions.

Since your media server won't be running Django, you'll need to modify the
deployment strategy to look something like:

    * When your media changes, run :djadmin:`collectstatic` locally.
    * Push your local :setting:`STATICFILES_ROOT` up to the media server
      into the directory that's being served. ``rsync`` is a good
      choice for this step since it only needs to transfer the
      bits of static media that have changed.

Here's how this might look in a fabfile::

    from fabric.api import *
    from fabric.contrib import project

    # Where the static files get collected locally
    env.local_static_root = '/tmp/static'

    # Where the static files should go remotely
    env.remote_static_root = '/home/www/media.example.com'

    @roles('media')
    def deploy_static():
        local('./manage.py collectstatic')
        project.rysnc_project(
            remote_dir = env.remote_static_root,
            local_dir = env.local_static_root,
            delete = True
        )

.. _staticfiles-from-cdn:

Serving static media from a cloud service or CDN
------------------------------------------------

Another common tactic is to serve media from a cloud storage provider like
Amazon's S3__ and/or a CDN (content delivery network). This lets you ignore the
problems of serving media, and can often make for faster-loading webpages
(especially when using a CDN).

When using these services, the basic workflow would look a bit like the above,
except that instead of using ``rsync`` to transfer your media to the server
you'd need to transfer the media to the storage provider or CDN.

There's any number of ways you might do this, but if the provider has an API a
:doc:`custom file storage backend </howto/custom-file-storage>` will make the
process incredibly simple. If you've written or are using a 3rd party custom
storage backend, you can tell :djadmin:`collectstatic` to use it by setting
:setting:`STATICFILES_STORAGE` to the storage engine.

For example, if you've written an S3 storage backend in
``myproject.storage.S3Storage`` you could use it with::

    STATICFILES_STORAGE = 'storages.backends.s3.S3Storage'

Once that's done, all you have to do is run :djadmin:`collectstatic` and your
media would be pushed through your storage package up to S3. If you later needed
to swich to a different storage provider, it could be as simple as changing your
:setting:`STATICFILES_STORAGE` setting.

For details on how you'd write one of these backends,
:doc:`/howto/custom-file-storage`.

.. seealso::

    The `django-storages`__ project is a 3rd party app that provides many
    storage backends for many common file storage APIs (including S3).

__ http://s3.amazonaws.com/
__ http://code.welldev.org/django-storages/wiki/S3Storage

Upgrading from ``django-staticfiles``
=====================================

``django.contrib.staticfiles`` began its life as `django-staticfiles`_. If
you're upgrading from `django-staticfiles`_ to ``django.contrib.staticfiles``,
you'll need to make a few changes:

    * Application files should now live in a ``static`` directory in each app
      (`django-staticfiles`_ used the name ``media``, which was slightly
      confusing).

    * The management commands ``build_static`` and ``resolve_static`` are now
      called :djadmin:`collectstatic` and :djadmin:`findstatic`.

    * The settings ``STATIC_URL`` and ``STATIC_ROOT`` were renamed to
      :setting:`STATICFILES_URL` and :setting:`STATICFILES_ROOT`.

    * The settings ``STATICFILES_PREPEND_LABEL_APPS``,
      ``STATICFILES_MEDIA_DIRNAMES`` and ``STATICFILES_EXCLUDED_APPS`` were
      removed.
      
    * The setting ``STATICFILES_RESOLVERS`` was removed, and replaced by the new
      :setting:`STATICFILES_FINDERS`.
      
    * The default for :setting:`STATICFILES_STORAGE` was renamed from
      ``staticfiles.storage.StaticFileStorage`` to
      ``staticfiles.storage.StaticFilesStorage``
      
Learn more
==========

This document has covered the basics and some common usage patterns. For
complete details on all the settings, commands, template tags, and other pieces
include in ``django.contrib.staticfiles``, see :doc:`the statcfiles reference
</ref/contrib/staticfiles>`.