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Re: Some general SPDY feedback / questions

From: James M Snell <jasnell@gmail.com>
Date: Thu, 9 Aug 2012 18:45:28 -0700
Message-ID: <CABP7RbdNWSm_qWwnnKks3NtKwWrNk5Sy_Tj85HjunZV3hx6aKg@mail.gmail.com>
To: "Adrien W. de Croy" <adrien@qbik.com>
Cc: Amos Jeffries <squid3@treenet.co.nz>, ietf-http-wg@w3.org, Mike Belshe <mike@belshe.com>
They're currently not forbidden but would be fairly pointless, so we may be
safe.
On Aug 9, 2012 5:09 PM, "Adrien W. de Croy" <adrien@qbik.com> wrote:

>
> do we even envisage sending entity headers on 1xx responses?
>
> I don't know if it's a good idea.
>
> in which case, we'd only get entity headers on the final response before
> the data.
>
> Adrien
>
>
>
> ------ Original Message ------
> From: "James M Snell" <jasnell@gmail.com>
> To: "Mike Belshe" <mike@belshe.com>
> Cc: "Amos Jeffries" <squid3@treenet.co.nz>;"ietf-http-wg@w3.org" <
> ietf-http-wg@w3.org>
> Sent: 10/08/2012 10:54:37 a.m.
> Subject: Re: Some general SPDY feedback / questions
>
>
> On Aug 9, 2012 2:26 PM, "Mike Belshe" <mike@belshe.com> wrote:
> >
> >
> [Snip]
> >
> >
> > When you do this, it opens up a new set of things to define:
> >    - what happens if a header is superseded later? can you send the same
> header twice?
>
> There is a definite trade off in complexity, that's for sure... but if we
> need to support 1xx responses I don't see another way to do it without
> increasing the complexity even further.
>
> Headers would essentially be single value, if a subsequent headers frame
> repeats a previously seen header, the value for that header is replaced. If
> the application has already processed that header, the application needs to
> figure out how to handle the situation.
>
> >    - when can a receiver know when headers are 'done'?  If you sent one
> set of cache-related headers, can you send further ones later?
>
> The headers are done once the first data frame is sent or the FIN is
> received.
>
> For cache headers, it would be important to note that repeated headers
> would replace the existing value, not add to the value, so subsequent cache
> control headers would supersede any that came before.
>
> >
> > I know these sound like edges, and even the spdy framer sort-of allows
> header frames at any time... but at the app layer, it creates a lot of new
> questions that http doesn't have today.  this is why in SPDY we just said
> "although the framing layer can do it, for HTTP's purposes, you (mostly)
> can't".
> >
>
> Understood, and the reasoning is sound, but there really doesn't appear to
> be another simpler way of supporting provisional responses. There is an
> increased burden on the developer to handle repeated headers properly but I
> doubt that burden is much more than what developers are already accustomed
> to.
>
> - James
>
> > Mike
> >
> >
> >
> >
> >>
> >>
> >> Amos
> >>
> >
>
>
Received on Friday, 10 August 2012 01:45:58 GMT

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