I, for one, would appreciate more details to better understand the needs. I'm not clear where the mime type fits in.
well, say you have an output filter that should only operate on a particular mime-type - like the mod_blanks that keeps coming up here. ideally, the filter should be able to do at least few things: remove (or weaken) the ETag, alter Last-Modified, and do it's filtering. the first two need to happen in filter_init because of default_handler and its logic, but with an unknown content-type the filter is in a quandry - if it calls update_mtime but doesn't run (not html) then it affected the cache status unnecessarily, but if it doesn't call update_mtime() then default_handler might return 304 before the filter can insert itself. the etag issue is similar.
this is a real life scenario, btw - something I've been working on :)
> Is it that > filter_init isn't called for AddOutputFilterByType filters?
I hadn't tried that, it would be interesting to see what ends up happening on AddOutputFilterByType filters when the content is a cgi script and content-type differs from DefaultType.
could be easily solved by moving ap_meets_conditions logic to it's own filter, which was the original proposal before filter_init won. as I use
Hmm. Would that filter be a CONTENT_SET (or PROTOCOL?) filter? If it thinks the response shouldn't be sent, would it throw away the response (so far) and send down the 'right' bits for a 304? Might work, but that seems rather late to make that decision. -- justin
well, I was thinking something along the lines of the C-L filter (whatever that is :) basically, if everybody calls update_mtime but leaves set_last_modified for the filter then each handler and filter gets the chance to add its criterion to Last-Modified without worrying about another module sending a premature 304. no_local_copy could be used when one participant knows what it is doing negates all caching.
granted, yes it seems late in the process if you're taking the time to compress a flat file only to send a 304 after, but as output filters get more complex, the non-content altering deflate model becomes the only circumstance I can think of where you actually desire the current behavior.
--Geoff
