id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
29241	ConditionalGetMiddleware and x-sendfile	TZanke	nobody	"We found a issue with ConditionalGetMiddleware in combination with apache x-sendfile (django-sendfile) and Django 1.11

In Django 1.10 we just use Last-Modified, which works fine. Now with Django 1.11 each response gets a ETag generated based on response.content. In the case of a x-sendfile response, the response.content is an empty string. So each time the file is accessed, the ETag generated by ConditionalGetMiddleware is the same. Regardless of the changed file/changed mtime.

So now the request has our Last-Modified header AND the Middleware generated ETag.
In get_conditional_response the ETag, which is always the same hash of empty string, is checked first and returns a 304. BUT the Last-Modification has changed and is ignored.

This looks like two bugs for me. First the ETag of the empty content string from x-sendfile respose. Second returning a 304 if ETag is the same but Last-Modified has changed."	Bug	new	Core (Cache system)	1.11	Normal		sendfile		Unreviewed	0	0	0	0	0	0