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Re: #158: Proxy-Connection and Keep-alive

From: Amos Jeffries <squid3@treenet.co.nz>
Date: Tue, 29 Nov 2011 19:01:08 +1300
Message-ID: <4ED47524.5060900@treenet.co.nz>
To: ietf-http-wg@w3.org
On 29/11/2011 1:29 a.m., Willy Tarreau wrote:
> On Tue, Nov 29, 2011 at 12:42:15AM +1300, Amos Jeffries wrote:
>> We seem not to have any troubles nowdays emitting only Connection. The
>> problems are on satisfying the sources who send Proxy-Connection still.
>> IMO it would be nice to have a guideline to point at stating that
>> Connection overrides Proxy-Connection and the latter should be ignored
>> for processing and never emitted.
> The issue for a client is that emitting nothing does not behave equally on
> all proxies. Older Squid assume a close and newer 1.1 products will behave
> with an implicit keep-alive. In theory sending "Connection: keep-alive" is
> useless, except that in this case it can be the solution for those products.
> Probably that the guideline should say that a client should explicitly send
> "Connection: keep-alive" if it does not know whether the proxy is 1.1 or 1.0
> and not use Proxy-Connection at all. I'm insisting on this point because
> just saying that Connection overrides Proxy-Connection can be confusing
> since the default behaviour for the Connection header differs from what
> clients have expected for a long time with Proxy-Connection.
> I would thus suggest the following rule for clients :
> Proxy's HTTP version                 Desired behaviour
>                                persistent             close
> 1.0                    Connection: keep-alive       nothing/close
> Unknown                Connection: keep-alive       Connection: close
> 1.1                    nothing/keep-alive           Connection: close
> However the issue remains for responses. In the example I sent this morning,
> my old squid 2.6-stable13 was only returning Proxy-Connection: keep-alive
> and no "connection" header. This will force clients to still consider the
> Proxy-Connection in responses from 1.0 proxies. The real issue precisely is
> exactly this case, where Connection is absent and Proxy-Connection returns
> something which differs from the implicit connection mode (1.0 without header
> means close).
> So we can't totally ignore this header but we should be able to prevent it
> from being emitted at least.
> Regards,
> Willy

Okay I'm with you on all points there.

How about is for prose:
  Proxy-Connection is now obsolete. Clients must not produce it on 
HTTP/1.1 requests or responses.
  NP: existing software still uses a mixture of HTTP/1.0 and obsolete 
Proxy-Connection keep-alive mechanisms which differ in behaviour from 
HTTP/1.1. Clients should always explicitly send Connection: keep-alive 
or Connection: close when contacting servers having HTTP/1.0 or unknown 
HTTP version numbers.

Received on Tuesday, 29 November 2011 06:01:47 UTC

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