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
29562	Allow the cache template tag to take a function that adds context data	HongWeipeng	nobody	"There is a problem in using template fragment caching, that is, we need transfer `data` for template every time, even the data has been in cache.

If the data acquisition process is time consuming (such as 3 seconds), template caching has no helpful.

My idea is to allow provide a callback function to tell the cache how to get the data. and only call the function when cache expires.

Although custom tags can be used to get the data in the cache, custom tags don't seem to handle html code very well.

I have tried it many times and found out how to make the simplest changes to complete this feature and ensure its compatibility.

Can you see this RP please? [https://github.com/django/django/pull/10176]"	New feature	closed	Template system	dev	Normal	wontfix			Unreviewed	0	0	0	0	0	0