OK anyway declaring it 'immutable' clarifies intent in a manner that's consistent with the wording quoted, so I'm in favor of it.
On Wed, Nov 29, 2017 at 10:18 AM, Otto van der Schaaf <[email protected]> wrote: > Quoting one of the comments from Patrick McManus: > > *"The core concept is that without immutable the concepts of fresh and > current are* > *not clearly separated. http caching allows for fresh (i.e. cache > replayable) data * > *that isn’t the most current representation of a resource – and of course > firefox * > *normally uses that. But when you press refresh we in the past have > revalidated * > *even fresh things (i.e. with a high max age) to check to see if they were > still the * > *most current. immutable lets the cache know that there is never more than > 1 * > *version of that resource, so we only need to worry about freshness and > never * > *re-validate under those circumstances."* > > From what I understand the behavior of browsers should change when pages > are > reloaded, for any resources linked that have cache-control: immutable. > > But.. I just tested, and I can not confirm that Chrome actually uses > revalidation > when I reload pages with cache-extended resources over at modpagespeed.com > . > It pulls them from its cache instead. > So it looks like this needs some more testing with other browsers, and > perhaps > proxies, to see if there are clear advantages. > > Otto > > > On Wed, Nov 29, 2017 at 3:31 PM Joshua Marantz <[email protected] > > > wrote: > > > This sounds like a reasonable idea to me. I agree that .pagespeed. URLs > > are a good candidate for this, as long as the hash is matching and > > therefore we are sending 1-year caching directives. > > > > However I'm confused why about why revalidation would be needed in such > > cases, even without 'immutable', unless the item has been in cache for >1 > > year. > > > > > > On Thu, Nov 23, 2017 at 3:33 PM, Otto van der Schaaf <[email protected] > > > > wrote: > > > > > Hi all, > > > > > > I wanted to discuss emitting the "immutable" cache-control directive in > > > responses for requests to .pagespeed. urls. > > > > > > After reading up on this fairly new cache-control directive, think we > may > > > be able to avoid revalidations by doing so. > > > The RFC mentions versioned urls as a candidate for doing this, which I > > > think also includes our fingerprinted .pagespeed. urls > > > (these have a hash that changes when any of the underlying resources > > > change) > > > > > > Rough implementation: > > > https://github.com/pagespeed/mod_pagespeed/compare/oschaaf- > > > cc-immutable?expand=1 > > > > > > Context: > > > https://hacks.mozilla.org/2017/01/using-immutable- > > > caching-to-speed-up-the-web/ > > > https://tools.ietf.org/html/rfc8246 > > > > > > Would love to hear thoughts on this! > > > > > > Otto > > > > > >
