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Re: [uriMediaType-9] New Internet Draft: Resrep Type

From: Mark Baker <distobj@acm.org>
Date: Wed, 27 Mar 2002 14:56:53 -0500 (EST)
Message-Id: <200203271956.OAA03468@markbaker.ca>
To: GK@NineByNine.org (Graham Klyne)
Cc: sean@mysterylights.com (Sean B. Palmer), www-tag@w3.org
Graham,

> Rather than defining new header field names, an alternative could be to 
> define media feature tags for use with the already-defined Content-features 
> [1] header.

Perhaps Repr-Type could used a feature tag, but Resource-Type cannot
because it is not an attribute of the content, it is an attribute of the
resource that the URI identifies.  It's my understanding that
Content-Features, as with other Content-* headers, describes resource
representations, not the resources themselves.

Also, a reason to be careful of feature tags is that they circumvent
reification in HTTP header assertions.  For example, if I wanted to say
that the negotiated content varied by some attribute that was expressed
as a feature tag rather than as an HTTP header, I cannot use the HTTP
Vary header.  Ditto for Connection, Man, Opt, or any other header with
headers as a subject.  Not that this is a concern for this draft, just
pointing out the potential downside.

MB
-- 
Mark Baker, Chief Science Officer, Planetfred, Inc.
Ottawa, Ontario, CANADA.      mbaker@planetfred.com
http://www.markbaker.ca   http://www.planetfred.com
Received on Wednesday, 27 March 2002 14:51:50 GMT

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