On Thu, 17 Nov 2011 02:54:54 +0200, Ghassan Gharabli wrote:
Hello, I was wondering what would we do with this URL http://www.youtube-nocookie.com/gen_204?attributionpartner=vevo if we want to cache it. I'e been looking and found that its expire header has an invalid date ! . I thought I can cache it since it has no-cache but as I can see the object can be cached & cant be served without validation. Isthere any other way that I can force it to cache ?
RFC 2048 (HTTP/1.0) requires that invalid Expires: headers are treated as already expired regardless of their value. Under HTTP/1.1 this could be cached and served stale.
However ... the status code is 204. Merely passing the URL to the web server changes some state there. Caching this could present clients with a lie, indicating that some server state has been changed when the server has not even been contacted. Also, the presence of no-cache and absence of max-stale means the server must be contacted on every re-use. Since there is no reply body content involved there is zero benefit from caching this. In fact a net loss in cache efficiency as one entry gets filled with an object which is guaranteed to be fully replaced on every usage.
Amos
