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.
- class UpdateCacheMiddleware¶
- class FetchFromCacheMiddleware¶
- class 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.
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.
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.
View metadata middleware¶
- class XViewMiddleware¶
- class GZipMiddleware¶
Compresses content for browsers that understand gzip compression (all modern browsers).
GZip compression can be applied to individual views using the gzip_page() decorator.
Conditional GET middleware¶
- class 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.
Reverse proxy middleware¶
- class SetRemoteAddrFromForwardedFor¶
This middleware was removed in Django 1.1. See the release notes for details.
- class LocaleMiddleware¶
Enables language selection based on data from the request. It customizes content for each user. See the internationalization documentation.
- class MessageMiddleware¶
Enables cookie- and session-based message support. See the messages documentation.
- class SessionMiddleware¶
Enables session support. See the session documentation.
- class AuthenticationMiddleware¶
Adds the user attribute, representing the currently-logged-in user, to every incoming HttpRequest object. See Authentication in Web requests.
CSRF protection middleware¶
- class CsrfMiddleware¶
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.
- class 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.