3 ms·

Meant to say that there's no conditional with immutable. Corrected, thanks.

• duskwuff 10y ago
  I still don't think that's accurate. My experience is that a future Expires date -- even relatively near-future -- is sufficient to prevent an If-Modified-Since request. (Which is what I think you mean by "304 request".)
  • jjoe 10y ago
    It's up to the client to decide based on Last-Modified (if previously sent by the server) and its own implementation. But I guess browsers are going to be a tad bit aggressive especially if Last-Modified is absent. Hence the overly aggressive 304s.
  • bzbarsky 10y ago
    For normal loads, yes. The problem people are trying to solve here is that users hit the relaod button. A lot. And if you hit the reload button, that will send If-Modified-Since for everything on the page, no matter what Expires says, because the user intent is to ignore Expires headers. That's what the immutable thing is about: indicating that even in the reload scenario the Expires is authoritative and no If-Modified-Since request should be sent.
    • duskwuff 10y ago
      Aha. The forced If-Modified-Since on reload is the piece I was missing. Thanks.