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Re: Design Issue: HEADERS+PRIORITY "MUST be used" for each stream that is created??

From: Roberto Peon <grmocg@gmail.com>
Date: Sat, 27 Apr 2013 14:44:00 -0700
Message-ID: <CAP+FsNdNxykDTDNmFrq4JfQDtLhH3Swtx9O3mxXd1PNRz97Eog@mail.gmail.com>
To: James M Snell <jasnell@gmail.com>
Cc: Martin Thomson <martin.thomson@gmail.com>, "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
The WS case may actually require headers as we do need to announce (per WS
'connection') the URL of the endpoint to which it is attaching/connecting.

On Fri, Apr 26, 2013 at 1:54 PM, James M Snell <jasnell@gmail.com> wrote:

> Well, until that case is made, we don't have very many good reasons to
> allow DATA frames with preceding headers-bearing frames. Also, keep in
> mind that it's perfectly legal to send a HEADERS frame with an empty
> set of HEADERS. It the WebSockets case does not require any preceding
> headers (which I rather doubt), it would still be simple enough to
> send an empty HEADERS frame to establish the stream before sending the
> DATA frames.
> On Fri, Apr 26, 2013 at 1:49 PM, Martin Thomson
> <martin.thomson@gmail.com> wrote:
> > On 26 April 2013 13:43, James M Snell <jasnell@gmail.com> wrote:
> >> I think I disagree on that point and say that I think it's much safer
> >> if we require that streams be initiated with only headers-bearing
> >> frames.
> >>
> >> Imagine, for instance, that a sender sends along a DATA frame with a
> >> new, previously unused stream identifier. Without an associated
> >> headers frame I have absolutely no context with which to determine
> >> what I need to do with that DATA frame. Likewise if I receive an
> >> RST_STREAM that references a previously unused stream identifier. If
> >> there's absolutely nothing that I can reliably do with it, or not
> >> reliable way that I can interpret it without additional context, then
> >> we should not allow it.
> >
> > I believe that this is exactly the scenario that the websockets
> > binding will take advantage of.  (Maybe there is some need to expose
> > some header information there, but that's a case that needs to be made
> > for that specific use of the framing layer.)
Received on Saturday, 27 April 2013 21:44:27 UTC

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