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Re: HTTP/2 Push deployed on webtide.com

From: Greg Wilkins <gregw@intalio.com>
Date: Tue, 19 Aug 2014 09:55:04 +1000
Message-ID: <CAH_y2NHwVay7ZLSh16V8eB0tmyLQS_fyvdRbUhifHv7XCWdB0w@mail.gmail.com>
To: Simone Bordet <sbordet@intalio.com>
Cc: HTTP Working Group <ietf-http-wg@w3.org>
Note that there is a thread on the Servlet EG list regarding an API for
push:

https://java.net/projects/servlet-spec/lists/jsr340-experts/archive/2014-08/message/1

where I've been asked some questions to describe "the rationalization used
by the httpbis wg"

Since I can't speak for the WG, I thought I'd echo my thoughts here
regarding the push mechanism to check that I'm not misrepresenting anything:

   - Push is a server-side coordinated mechanism in as much as the server
   must decide to push a resourced based only on information that it already
   has.   Specifically h2 provides no information on the contents or status of
   downstream caches.
   - Servers are free to innovate push strategies, with some of the
   following having been suggested:
      - Use knowledge from the web application/framework to determine what
      are associated resources.
      - Use heuristics derived from referrer headers and timing to infer
      what are associated resources
      - Use sessions to track what resources a client has
      requested/received to avoid unnecessary pushes
      - Use the presence of if-modified headers to infer the status of a
      client cache to avoid unnecessary pushes.
      - There are no functional problems other than increased latency of
   not pushing an associated resource
   - There are no functional problems other than wasted bandwidth of
   pushing an unnecessary resource:
      - Clients can reset a pushed stream if they determine it is
      unnecessary.   Thus is a server attempts to push a resource that
is already
      cached by the client, a RST will prevent wasting too much bandwidth.


Hopefully nothing controversial or misrepresented there?

cheers



On 18 August 2014 18:57, Simone Bordet <sbordet@intalio.com> wrote:

> Hi,
>
> the Jetty team has deployed h2-14 with HTTP/2 Push functionality on
> https://webtide.com, see
> https://webtide.com/http2-push-with-experimental-servlet-api/.
>
> We are very interested in comments about how to make HTTP/2 Push
> better, so please try it out and tell us (also see discussion bullets
> towards the end of blog post).
>
> Thanks !
>
> --
> Simone Bordet
> ----
> http://cometd.org
> http://webtide.com
> http://intalio.com
> Developer advice, training, services and support
> from the Jetty & CometD experts.
> Intalio, the modern way to build business applications.
>
>


-- 
Greg Wilkins <gregw@intalio.com>
http://eclipse.org/jetty HTTP, SPDY, Websocket server and client that scales
http://www.webtide.com  advice and support for jetty and cometd.
Received on Monday, 18 August 2014 23:55:32 UTC

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