How do Expires headers and cache manifest rules work together?
- by Robert K
I find the W3C's official Offline Web Applications specification to be rather vague about how the cache manifest interacts with headers such as ETag, Expires, or Pragma on cached assets. I know that the manifest should be checked with each request so that the browser knows when to check the other assets for updates. But because the specification doesn't define how the cache manifest interacts with normal cache instructions, I can't predict precisely how the browser will react.
Will assets with a future expiration date be refreshed (no matter the cache headers) when the cache manifest is updated? Or, will those assets obey the normal caching rules?
Which caching mechanism, HTTP cache versus cache manifest, will take precedence, and when?
