This document explains all middleware components that come with Django. For information on how to use them and how to write your own middleware, see the middleware usage guide.
UpdateCacheMiddleware
¶FetchFromCacheMiddleware
¶Enable the site-wide cache. If these are enabled, each Django-powered page will
be cached for as long as the CACHE_MIDDLEWARE_SECONDS
setting
defines. See the cache documentation.
CommonMiddleware
¶Adds a few conveniences for perfectionists:
Forbids access to user agents in the DISALLOWED_USER_AGENTS
setting, which should be a list of strings.
Performs URL rewriting based on the APPEND_SLASH
and
PREPEND_WWW
settings.
If APPEND_SLASH
is True
and the initial URL doesn’t end
with a slash, and it is not found in the URLconf, then a new URL is
formed by appending a slash at the end. If this new URL is found in the
URLconf, then Django redirects the request to this new URL. Otherwise,
the initial URL is processed as usual.
For example, foo.com/bar
will be redirected to foo.com/bar/
if
you don’t have a valid URL pattern for foo.com/bar
but do have a
valid pattern for foo.com/bar/
.
If PREPEND_WWW
is True
, URLs that lack a leading “www.”
will be redirected to the same URL with a leading “www.”
Both of these options are meant to normalize URLs. The philosophy is that
each URL should exist in one, and only one, place. Technically a URL
foo.com/bar
is distinct from foo.com/bar/
– a search-engine
indexer would treat them as separate URLs – so it’s best practice to
normalize URLs.
Sends broken link notification emails to MANAGERS
if
SEND_BROKEN_LINK_EMAILS
is set to True
.
Handles ETags based on the USE_ETAGS
setting. If
USE_ETAGS
is set to True
, Django will calculate an ETag
for each request by MD5-hashing the page content, and it’ll take care of
sending Not Modified
responses, if appropriate.
XViewMiddleware
¶Sends custom X-View
HTTP headers to HEAD requests that come from IP
addresses defined in the INTERNAL_IPS
setting. This is used by
Django’s automatic documentation system.
Depends on AuthenticationMiddleware
.
GZipMiddleware
¶Compresses content for browsers that understand GZip compression (all modern browsers).
It is suggested to place this first in the middleware list, so that the compression of the response content is the last thing that happens.
It will NOT compress content if any of the following are true:
Content-Encoding
header.Accept-Encoding
header
containing gzip
.Content-Type
header
contains javascript
or starts with anything other than text/
.
We do this to avoid a bug in early versions of IE that caused decompression
not to be performed on certain content types.You can apply GZip compression to individual views using the
gzip_page()
decorator.
ConditionalGetMiddleware
¶Handles conditional GET operations. If the response has a ETag
or
Last-Modified
header, and the request has If-None-Match
or
If-Modified-Since
, the response is replaced by an
HttpNotModified
.
Also sets the Date
and Content-Length
response-headers.
SetRemoteAddrFromForwardedFor
¶This middleware was removed in Django 1.1. See the release notes for details.
LocaleMiddleware
¶Enables language selection based on data from the request. It customizes content for each user. See the internationalization documentation.
MessageMiddleware
¶MessageMiddleware
was added.Enables cookie- and session-based message support. See the messages documentation.
SessionMiddleware
¶Enables session support. See the session documentation.
AuthenticationMiddleware
¶Adds the user
attribute, representing the currently-logged-in user, to
every incoming HttpRequest
object. See Authentication in Web requests.
CsrfViewMiddleware
¶Adds protection against Cross Site Request Forgeries by adding hidden form fields to POST forms and checking requests for the correct value. See the Cross Site Request Forgery protection documentation.
TransactionMiddleware
¶Binds commit and rollback to the request/response phase. If a view function runs successfully, a commit is done. If it fails with an exception, a rollback is done.
The order of this middleware in the stack is important: middleware modules running outside of it run with commit-on-save - the default Django behavior. Middleware modules running inside it (coming later in the stack) will be under the same transaction control as the view functions.
See the transaction management documentation.
XFrameOptionsMiddleware
¶XFrameOptionsMiddleware
was added.Simple clickjacking protection via the X-Frame-Options header.
Jul 07, 2017