django/docs/ref/contrib/redirects.txt

121 lines
4.4 KiB
Plaintext

=================
The redirects app
=================
.. module:: django.contrib.redirects
:synopsis: A framework for managing redirects.
Django comes with an optional redirects application. It lets you store
redirects in a database and handles the redirecting for you. It uses the HTTP
response status code ``301 Moved Permanently`` by default.
Installation
============
To install the redirects app, follow these steps:
#. Ensure that the ``django.contrib.sites`` framework
:ref:`is installed <enabling-the-sites-framework>`.
#. Add ``'django.contrib.redirects'`` to your :setting:`INSTALLED_APPS` setting.
#. Add ``'django.contrib.redirects.middleware.RedirectFallbackMiddleware'``
to your :setting:`MIDDLEWARE` setting.
#. Run the command :djadmin:`manage.py migrate <migrate>`.
How it works
============
``manage.py migrate`` creates a ``django_redirect`` table in your database. This
is a lookup table with ``site_id``, ``old_path`` and ``new_path`` fields.
The :class:`~django.contrib.redirects.middleware.RedirectFallbackMiddleware`
does all of the work. Each time any Django application raises a 404
error, this middleware checks the redirects database for the requested
URL as a last resort. Specifically, it checks for a redirect with the
given ``old_path`` with a site ID that corresponds to the
:setting:`SITE_ID` setting.
* If it finds a match, and ``new_path`` is not empty, it redirects to
``new_path`` using a 301 ("Moved Permanently") redirect. You can subclass
:class:`~django.contrib.redirects.middleware.RedirectFallbackMiddleware`
and set
:attr:`~django.contrib.redirects.middleware.RedirectFallbackMiddleware.response_redirect_class`
to :class:`django.http.HttpResponseRedirect` to use a
``302 Moved Temporarily`` redirect instead.
* If it finds a match, and ``new_path`` is empty, it sends a 410 ("Gone")
HTTP header and empty (content-less) response.
* If it doesn't find a match, the request continues to be processed as
usual.
The middleware only gets activated for 404s -- not for 500s or responses of any
other status code.
Note that the order of :setting:`MIDDLEWARE` matters. Generally, you can put
:class:`~django.contrib.redirects.middleware.RedirectFallbackMiddleware` at the
end of the list, because it's a last resort.
For more on middleware, read the :doc:`middleware docs
</topics/http/middleware>`.
How to add, change and delete redirects
=======================================
Via the admin interface
-----------------------
If you've activated the automatic Django admin interface, you should see a
"Redirects" section on the admin index page. Edit redirects as you edit any
other object in the system.
Via the Python API
------------------
.. class:: models.Redirect
Redirects are represented by a standard :doc:`Django model </topics/db/models>`,
which lives in :source:`django/contrib/redirects/models.py`. You can access
redirect objects via the :doc:`Django database API </topics/db/queries>`.
For example:
.. code-block:: pycon
>>> from django.conf import settings
>>> from django.contrib.redirects.models import Redirect
>>> # Add a new redirect.
>>> redirect = Redirect.objects.create(
... site_id=1,
... old_path='/contact-us/',
... new_path='/contact/',
... )
>>> # Change a redirect.
>>> redirect.new_path = '/contact-details/'
>>> redirect.save()
>>> redirect
<Redirect: /contact-us/ ---> /contact-details/>
>>> # Delete a redirect.
>>> Redirect.objects.filter(site_id=1, old_path='/contact-us/').delete()
(1, {'redirects.Redirect': 1})
Middleware
==========
.. class:: middleware.RedirectFallbackMiddleware
You can change the :class:`~django.http.HttpResponse` classes used
by the middleware by creating a subclass of
:class:`~django.contrib.redirects.middleware.RedirectFallbackMiddleware`
and overriding ``response_gone_class`` and/or ``response_redirect_class``.
.. attribute:: response_gone_class
The :class:`~django.http.HttpResponse` class used when a
:class:`~django.contrib.redirects.models.Redirect` is not found for the
requested path or has a blank ``new_path`` value.
Defaults to :class:`~django.http.HttpResponseGone`.
.. attribute:: response_redirect_class
The :class:`~django.http.HttpResponse` class that handles the redirect.
Defaults to :class:`~django.http.HttpResponsePermanentRedirect`.