[cm2187]

Server push can’t be free. You need the web server to somehow know what resources will be required by the page and I still don’t understand how it doesn’t defeat browser caching but I presume it must involve some non trivial configuration.

[johncolanduoni]

Server push also isn’t required to reap most of the benefits. In the places where I’ve tried it I’ve not seen any benefit over link preload headers + HTTP2 without push. Many CDNs that support HTTP2 haven’t bothered to support server push at all, I suspect due to the limited advantages compared to the extra complexity.

[youngtaff]

Pretty sure server push is being deprecated - current implementation is 'only half a feature', as clients lack the ability to tell the server what's already in cache.

In theory the client can cancel the response for a resource it's already got but by the time the response bytes reach the client it's really too late

[cm2187]

Yeah and if the client volunteers the list of all it has in cache it would result in some massive requests and a kind of quasi-cookie.

I always found this feature interesting but weird.

[VBprogrammer]

Random thought. But isn't this a potential use for a bloom filter?

[youngtaff]

Yes bloom filters were a potential for Cache Digests, original prototype for Cache Digests used Golomb coded set as memory representation is smaller than Bloom filter

https://github.com/h2o/h2o/issues/421

But then Cache Digests moved onto Cuckoo Filters - https://github.com/httpwg/http-extensions/pull/413

[zaarn]

Your webapp needs to start the push, browsers will interrupt it if they find the resource is already in cache after it has parsed the HTML.