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Re: #516 note about WWW-A parsing potentially misleading

From: Michael Sweet <msweet@apple.com>
Date: Wed, 30 Oct 2013 11:00:32 -0400
Cc: "ietf-http-wg@w3.org Group" <ietf-http-wg@w3.org>
Message-id: <D67DCE54-D4E1-4B0B-8BA5-12EDDFC91C77@apple.com>
To: Julian Reschke <julian.reschke@gmx.de>
Julian,

On Oct 30, 2013, at 10:50 AM, Julian Reschke <julian.reschke@gmx.de> wrote:
> On 2013-10-30 15:39, Michael Sweet wrote:
>> Julian,
>> 
>> This might be a case of what-is-defined vs. what-is-used, but in my experience user agents/clients don't support multiple WWW-Authenticate headers and often do not look past the first challenge in the value.
> 
> Multiple challenges in one header field: <http://greenbytes.de/tech/tc/httpauth/#multibasicunknown2> (fail for everyone except Safari and Konqueror)
> 
> Multiple header field instances: <http://greenbytes.de/tech/tc/httpauth/#multibasicunknown2mf> (seems to work interoperably)

I'm glad to see the multiple header situation has improved; my last experiments with this 3-4 years ago (trying to support simultaneous Basic and Negotiate auth for CUPS) were not successful at all...

>> Given that the current p1-messaging draft says that senders MUST NOT repeat headers (section 3.2.2) and that WWW-Authenticate is not listed as an exception like Set-Cookie, I think it would be appropriate/safe to drop the "or if more than one WWW-Authenticate header field is provided" part in p7-auth.
> 
> <http://greenbytes.de/tech/webdav/draft-ietf-httpbis-p1-messaging-24.html#rfc.section.3.2.2.p.2>:
> 
> "A sender MUST NOT generate multiple header fields with the same field name in a message unless either the entire field value for that header field is defined as a comma-separated list [i.e., #(values)] or the header field is a well-known exception (as noted below)."
> 
> So WWW-Authenticate does not need to be listed as exception because it *does* use the list syntax.
> 
> Best regards, Julian
> 

_________________________________________________________
Michael Sweet, Senior Printing System Engineer, PWG Chair
Received on Wednesday, 30 October 2013 14:59:59 UTC

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