middleware.common.CommonMiddleware

class CommonMiddleware [source]

Adds a few conveniences for perfectionists:

• Forbids access to user agents in the DISALLOWED_USER_AGENTS setting, which should be a list of compiled regular expression objects.

• 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.

• 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.