On 5/17/07, Ruediger Pluem <[EMAIL PROTECTED]> wrote:
But it already does in the case of the Expires header. If the Expires header is missing or bogus and no max-age field is present (valid or invalid), we set one with the expires date the cache calculated (either heuristic or default). And this creates the next question for me: Why always use the default expire setting in the case of a bogus max-age? In the case of a bogus Expire header we try to calculate a heuristic expiration date using the Last-Modified header (if present and valid). I think we should handle Expires and max-age in the same way here.
My concern with falling back to the Last-Modified date on a bogus Cache-Control max-age field is that the server was *trying* to tell us something via the max-age field. So, falling back to Last-Modified seems wrong-ish. I'd rather just stay silent here and go with our default value. BTW, I'm not a fan of us inventing Expires headers in this section of code - I'd think it'd be far cleaner to off-load Expires response header generation to mod_expires and leave the cache out of it entirely - inventing Expires values deep inside of mod_cache seems unclean. mod_cache, IMO, should just respect what it is told and not change how things appear to downstream folks. (mod_expires is more than capable of inserting in the Expires header if the admin wants it.)
> shouldn't tweak the value under any circumstances. > > I can be convinced that's the wrong approach and that we should indeed > normalize it in the event of an error, but my gut says letting is just > pass-through seems right. -- justin But shouldn't the client have the same expiration expectation as the cache? In the case of an invalid max-age field I would see it as a correct decision by a client to ignore it completely for its local cache and thus possibly do not cache it at all.
Since the cache is not authoritative, I think it's slightly sketchy for us to tweak any downstream value based on our local policy decisions. Does my position make sense? I'm of the opinion that we should go one of two ways: - mod_cache shouldn't touch the response - so it stops setting Expires or anything like that which affects cachability - mod_cache always tweaks the response - so my CC: max-age fix needs to mimic what we do for Expires. WDYT? -- justin
