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Re: Comments on draft-ietf-http-negotiation-00.txt

From: Paul Sutton <paul@ukweb.com>
Date: Thu, 20 Feb 1997 13:16:57 +0000 (GMT)
To: Koen Holtman <koen@win.tue.nl>
Cc: http-wg@cuckoo.hpl.hp.com
Message-Id: <Pine.LNX.3.95.970220130140.7803E-100000@aardvark.localnet>
X-Mailing-List: <http-wg@cuckoo.hpl.hp.com> archive/latest/2500
On Wed, 19 Feb 1997, Koen Holtman wrote:
> Roy T. Fielding:
> >I really don't care whether or not they are part of TCN -- what is important
> >is that TCN not screw-over other forms of negotiation (namely, agent-driven)
> >that also use the Alternates information, but without any need for
> >contortions due to transparency.
> Ah, so *that* is your problem.  Well, I see Alternates as intimately
> connected to TCN, while the concept of a variant list is more general.  In
> the TCN spec, the Alternates header acts as a flag to proxies that this
> response is transparently negotiated.  If you want to use variant lists
> outside of TCN, you should put them in another header.

I must admin I would prefer it if Alternates is defined in the tcn draft
as valid for any response where the server has multiple representations of
the resource (whether or not a tcn rvsa algorithm was used). 

I would also like to be able to respond with 300 Multiple Choices and
ad-hoc responses after the server has applied _any_ algorithm (where both
of these include an Alternates header, but where this does _not_
necessarily indicate that a rvsa algorithm from the Negotiate request
header, if any, was used). 

Perhaps (and I haven't thought this through) the variant-validator should
have it's own header rather than being stuck onto the end of the ETag, and
that this header (say "TCN-Etag") should indicate authoritatively whether
tcn was used on the server. It could also be used to indicate what version
of rvsa was used.

> If you think that the 1.1 spec reserves Alternates for all forms of
> agent-driven negotiation, and that TCN should use some other kind of flag if
> it needs one, then say so.

I agree with this idea.

Paul Sutton, Technical Director, UK Web ---- http://www.ukweb.com/~paul/
Editor, Apache Week .. the latest Apache news http://www.apacheweek.com/
Received on Thursday, 20 February 1997 05:19:27 UTC

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