Deprecate GzipMiddleware

[Aymeric Augustin]

Per ​PEP 3333:

applications and middleware must not apply any kind of Transfer-Encoding to their output, such as chunking or gzipping; as "hop-by-hop" operations, these encodings are the province of the actual web server/gateway.

Since WSGI has become by far the most common way to deploy Django — I don't even know any other way — Django should stop providing GzipMiddleware.

This idea was approved by a BDFL on IRC:

20-00:10:33     jacobkm Oh and +1 on deprecating gzip middleware

[Claude Paroz]

​https://github.com/django/django/pull/455

[Tomáš Ehrlich]

Doesn't merge cleanly against master, since docs/releases/1.5.txt is probably intensively updated before release.
Patch works anyway.

[Aymeric Augustin]

If it doesn't merge then it isn't ready for checkin :)

I created a ticket instead of doing it myself because I think this deserves a serious discussion. Even though gzipping at the application level in wrong in theory, tons of people are doing it and it works in practice.

I'd like to see a discussion on django-developers before proceeding with this deprecation.

[Tomáš Ehrlich]

Oh, I'm sorry, the problem with merge was only in docs/releases/1.5.txt and it was trivial one.

[Aymeric Augustin]

Since filing this bug, I've come across a use case for GzipMiddleware.

It requires running Django with USE_ETAGS = True behind nginx, with gzip compression enabled. In this situation, nginx will remove the etag (in modern versions) or keep it unchanged (in older versions). To get the correct behavior — ie. gzipping if the client supports it, and a different etag for the gzipped and non-gzipped version — you have to do the compression in Django.

Related: #19705 and #16035.

[Tim Graham]

Should we mark this as "won't fix" then?

[alubbock]

This is an old ticket, but I thought it worth noting that recent versions of nginx will now downgrade the Django-generated etag to a "weak" etag rather than deleting it altogether when using nginx's gzip. At least for nginx users, this seems to remove the need for gzip middleware.