Re: Submitted new I-D: Cache Digests for HTTP/2

[Stefan Eissing <[e-mail]>]

Is PUSHing a HEAD request, unconditional, not what you are looking for?

> Am 10.02.2016 um 02:50 schrieb Kazuho Oku <[e-mail]>:
> 
> Hi,
> 
> 2016-02-09 20:46 GMT+09:00 Alcides Viamontes E <[e-mail]>:
>>>> Not something that we've implemented yet, but it's a valid scenario.
>> 
>> Pushing 304 works both in Chrome and Firefox:
>> https://drive.google.com/open?id=0B2F2m0rSqGCVWFJnTzRWOWFWQmc , we have been
>> doing it for some time.
> 
> My understanding is that handling of pushed 304 in Chrome and Firefox
> is unreliable.
> 
> When sending a push, a server cannot be 100% certain if the client has
> the resource cached.  In other words, there is always a possibility
> that the pushed response will be considered as a response to a
> non-conditional HTTP request on the client side.
> 
> In other words, browsers that support 304 push should, when matching a
> pushed 304 response against a HTTP request, check that the request is
> conditional, and use the pushed response only if the request was
> conditional (additional checks might be necessary).  Otherwise, the
> pushed 304 request must be ignored, and the browser should pull the
> unconditional HTTP request.
> 
> However, my understanding is that both Chrome (48.0.2564.103) and
> Firefox (44.0.1) don't do the check; they consider pushed 304
> responses to be a response to a unconditional HTTP request.
> Therefore, there is a chance that you would fail to deliver the
> correct content if you use 304 push today.
> 
> -- 
> Kazuho Oku
>