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Re: Expect: 100-continue and proxies

From: Adrien de Croy <adrien@qbik.com>
Date: Fri, 14 May 2010 23:20:34 +1200
Message-ID: <4BED3202.3060502@qbik.com>
To: Henrik Nordström <henrik@henriknordstrom.net>
CC: Joe Orton <joe@manyfish.co.uk>, ietf-http-wg@w3.org

On 14/05/2010 9:52 p.m., Henrik Nordström wrote:
> mån 2010-02-22 klockan 09:36 +0000 skrev Joe Orton:
> '
>> Ah, I wasn't clear here: httpd/mod_proxy will, given a request
>> containing "Expect: 100-continue":
>> 1) send the request including the Expect header to the next hop
>> 2) generate and send a "100 Continue" to the client
> 2 there is a clear violation. Intermediaries MUST NOT generate 1xx
> responses.

does this really apply to all 1xx responses, or just 100-continue (which 
is the only one defined for Expects)?

Just thinking about my I-D about progress notifications, which relies on 
intermediaries potentially inserting 102 or other (as yet undefined 1xx 
code) to indicate progress state.

On that note, is  there any interest in resuscitating this I-D?  It's 
still a major problem (AV scanning at an HTTP gateway).  In fact the 
problem just keeps getting worse.



>> 3) read the request body from the client and forward it to the next hop
>> 4) read the response from the next hop and forward it to the client
>> So I guess this seems to comply with the letter of 2616 ("MUST forward
>> the request, including the Expect header field") but not the spirit:
>> that Expect is handled end-to-end, not hop-by-hop.
> Err.
> Expect is supposed to be handled hop-by-hop but sent end-to-end. There
> is severaly MUST NOT forward the request clauses attached to Expect.
> 1xx responses is end-to-end.
> 417 responses is used at hop-by-hop Expect processing to signal that the
> expectation can not be met if needed.
> Regards
> Henrik

Adrien de Croy - WinGate Proxy Server - http://www.wingate.com
Received on Friday, 14 May 2010 11:21:17 UTC

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