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Re: [apps-discuss] Re-review of draft-snell-http-prefer-15

From: James M Snell <jasnell@gmail.com>
Date: Tue, 16 Oct 2012 12:33:34 -0700
Message-ID: <CABP7RbeU5vmUHb8FsHfnQf+Eyj1fYOGaL-f4robrOOQE3aNZEg@mail.gmail.com>
To: Jan Algermissen <jan.algermissen@nordsc.com>
Cc: Mark Nottingham <mnot@mnot.net>, Barry Leiba <barryleiba@computer.org>, HTTP Working Group <ietf-http-wg@w3.org>, Apps Discuss <apps-discuss@ietf.org>
On Sat, Oct 13, 2012 at 2:08 PM, Jan Algermissen <jan.algermissen@nordsc.com
> wrote:

>
> On Oct 13, 2012, at 10:39 PM, Mark Nottingham wrote:
>
> >
> > On 14/10/2012, at 6:11 AM, James M Snell <jasnell@gmail.com> wrote:
> >
> >>> Right, but what's the difference between:
> >>>
> >>>  Prefer: wait=10
> >>> and
> >>>  Prefer: return-asynch, wait=10
> >>>
> >>> ? "return asynch" really says "give me a 202" which is nonsense; the
> client doesn't control the status code, the server does.
> >>>
> >>
> >> That's why it's a Prefer header and not Expect. The server retains
> control. "Prefer: wait=10" could just as easily result in the server simply
> throwing up it's hands and saying, "sorry, can't do it"
> >
> > And what does return-async(h) bring to the party?
>
> I cannot see that either. In fact, I cannot even imagine a server paying
> attention to the '10', given the juggling between estimating the task
> duration and comparing to the wait time.
>
> Maybe
>
>   Prefer: wait
>
> just does the job?
>

No, wait simply tells the server how long the client expects processing of
the request to take and does not communicate any information about the
preferred response. I could, for instance, have a theoretical "Prefer:
wait=120, respond-giveup" that could be interpreted as "I prefer you give
up if you can't process this request in less than 2 minutes".

- James


>
> Jan
>
>
> >
> > The server can still throw up its hands with a 4xx or 5xx, and the
> client has to deal with that.
> >
> >
> >
> > --
> > Mark Nottingham   http://www.mnot.net/
> >
> >
> >
> >
>
>
Received on Tuesday, 16 October 2012 19:34:22 GMT

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