Re: The role of media types for XML content

Mark Baker <distobj@acm.org> Fri, 10 June 2005 14:54 UTC

Received: from above.proper.com (localhost.vpnc.org [127.0.0.1]) by above.proper.com (8.12.11/8.12.9) with ESMTP id j5AEsdGJ018610; Fri, 10 Jun 2005 07:54:39 -0700 (PDT) (envelope-from owner-ietf-xml-mime@mail.imc.org)
Received: (from majordom@localhost) by above.proper.com (8.12.11/8.12.9/Submit) id j5AEsdWV018609; Fri, 10 Jun 2005 07:54:39 -0700 (PDT)
X-Authentication-Warning: above.proper.com: majordom set sender to owner-ietf-xml-mime@mail.imc.org using -f
Received: from bork.markbaker.ca (static-80-155.dsl.cuic.ca [216.126.80.155] (may be forged)) by above.proper.com (8.12.11/8.12.9) with ESMTP id j5AEsc47018603 for <ietf-xml-mime@imc.org>; Fri, 10 Jun 2005 07:54:38 -0700 (PDT) (envelope-from distobj@acm.org)
Received: from mbaker by bork.markbaker.ca with local (Exim 3.36 #1 (Debian)) id 1Dgkuj-0004p1-00; Fri, 10 Jun 2005 10:55:17 -0400
Date: Fri, 10 Jun 2005 10:55:17 -0400
From: Mark Baker <distobj@acm.org>
To: MURATA Makoto <murata@hokkaido.email.ne.jp>
Cc: ietf-xml-mime@imc.org
Subject: Re: The role of media types for XML content
Message-ID: <20050610145517.GD11241@markbaker.ca>
References: <20050609213820.2A95.MURATA@hokkaido.email.ne.jp> <20050609151226.GZ11241@markbaker.ca> <20050610075729.3CBD.MURATA@hokkaido.email.ne.jp>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <20050610075729.3CBD.MURATA@hokkaido.email.ne.jp>
User-Agent: Mutt/1.5.6+20040907i
Sender: owner-ietf-xml-mime@mail.imc.org
Precedence: bulk
List-Archive: <http://www.imc.org/ietf-xml-mime/mail-archive/>
List-ID: <ietf-xml-mime.imc.org>
List-Unsubscribe: <mailto:ietf-xml-mime-request@imc.org?body=unsubscribe>

Hey,

On Fri, Jun 10, 2005 at 08:04:28AM +0900, MURATA Makoto wrote:
> Mark,
> 
> (I do think that this topic belongs to the ietf-xml-mime ML.  I am 
> ccing to the ietf-types but will not do so any more.)

Sounds good.

For those on ietf-xml-mime and not on ietf-types, my original
message can be found here;

http://eikenes.alvestrand.no/pipermail/ietf-types/2005-June/000817.html

> I think that you have presented some requirements which are not
> addressed by any of the existing mechanisms. 
> 
> > But I believe the security problem is just one manifestation of the
> > layering problem inherrent in using intrinsic dispatch (of which XML
> > namespace dispatch in one kind); that an extrinsic dispatch mechanism,
> > like media types, cleanly separates the "what" - the raw data - from
> > the "how" - the semantics with which that data is to be interpreted.
> 
> I do not think that media types are good enough for multi-namespace 
> documents and that W3C should develop something different.

I think media types are fine for multi-namespace documents.  I just
think that XML, by itself, doesn't provide a sufficiently rich framework
to address the root cause of the need for an explosion of media types
with these documents.

Consider RDF/XML documents, almost all of which are comprised of data
from several independent namespaces.  Yet a single media type,
application/rdf+xml, suffices for (almost[1]) all RDF/XML documents.

>Although 
> your example can be addressed by specialized media types, my example 
> (schemas embedded within XHTML are referenced by XPointer) cannot.

Can you elaborate on that example please?  I don't think I've seen any
schemas embedded in XHTML before.

Cheers,

 [1] http://esw.w3.org/topic/RdfAndMediaTypes

Mark.
-- 
Mark Baker.  Ottawa, Ontario, CANADA.          http://www.markbaker.ca
Coactus; Web-inspired integration strategies   http://www.coactus.com