on 06/06/2006 14:50 Joshua Slive said the following:
On 6/6/06, Matthew Claridge <mclaridge@xxxxxxxxxxxxx> wrote:on 06/06/2006 14:30 Joshua Slive said the following: > On 6/6/06, Matthew Claridge <mclaridge@xxxxxxxxxxxxx> wrote:>> We've looked into mod_expiry, but this doesn't really work, because as>> soon as the expiry time is reached the browser starts requesting it>> again and a new expiry is never set until the server actually sends the >> image, so we can make this work with huge expiry times, but thats just >> not practical as it means the images are never requested even if we've>> changed them. > > > Two issues here: > > 1. The server should indeed be updating the Expires and Cache-Control > headers even on 304 responses. See RFC2616 section 10.3.5. If it is > not doing that, it is a bug. (It may also be a bug in the client that > ignores the updated Cache-Control.) > > 2. A good practice is to set very-long expire (Cache-Control: max-age) > headers on your images and then *never* change them. If you need to > update the content, use a different filename. Of course, I believe > most browsers and caches tend to ignore expiry dates more than a day > or so in the future anyway.Thanks for this. I originally thought your first point was correct and that this was a bug. Certainly it was reported as a bug in version 1.1.1 However, the docs for v2 state that once the expiry has passed, that copy of the file is considered invalid and a new copy of the file MUST be obtained from the server. This will of course never happen because the server just sends 304s :-)The documentation you quote is just a general statement to help people understand how cache-control works. It is not an authoratative documentation on http caching rules. That is contained RFC2616. In this context, "a new copy" should also include a 304 response with an updated expiry time. Have you actually tested this? It should be easy enough to just make sure that apache is updating cache-control headers in 304 responses. No point arguing theoretically over something that is so easy to test.
Fair enough....I'm just reading it wrong :-)Apache does send a Cache-control header of "max-age=0", which if I'm right means it isn't updatiing the expiry time?
Matt --------------------------------------------------------------------- The official User-To-User support forum of the Apache HTTP Server Project. See <URL:http://httpd.apache.org/userslist.html> for more info. To unsubscribe, e-mail: users-unsubscribe@xxxxxxxxxxxxxxxx " from the digest: users-digest-unsubscribe@xxxxxxxxxxxxxxxx For additional commands, e-mail: users-help@xxxxxxxxxxxxxxxx
|