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RE: SOAP MIME Type

From: John J. Barton <John_Barton@hpl.hp.com>
Date: Mon, 12 May 2003 11:59:14 -0700
Message-Id: <5.1.1.6.2.20030512110300.02735fb0@hplex1.hpl.hp.com>
To: noah_mendelsohn@us.ibm.com, "David Orchard" <dorchard@bea.com>
Cc: "'Don Box'" <dbox@microsoft.com>, "'Mark Baker'" <distobj@acm.org>, "'John Kemp'" <john.kemp@earthlink.net>, "'Mark Nottingham'" <mark.nottingham@bea.com>, "'Xml-Dist-App@W3. Org'" <xml-dist-app@w3.org>

Ok here is a bit of a philosophical argument on the URI vs MIME issues.
I agree with Noah that this subject deserves more thought.  I understand the
desire to push for a URI-based system for identifying content, but the
systemic consequences of this choice may be both undesired and boring.
That is, its an ok thing, but its also just a way-point.  Let me see if I can
help the next stage:

The two extreme solutions to distributed systems that we know work
are 1)  loosely coupled public agreement (think web pages).  2) tightly
coupled private agreement (think RPC et al).  The first solution is
centralized; the second one is not.  Centralization is valuable even
if it is costly: it seems to be the only way to get breadth in electronic
communications. The ultimate ability of the decentralized solution to enable
wide-spread electronic communications is both logically and experimentally
limited. After all we cannot talk unless we first agree on the meaning of our
words.  The more of us agree, the more interchange we can have.  The
tightly coupled solution requires us all to acquiesce to a monolithic
proprietary meaning to communicate; the loosely coupled solution allows
variety and diversity.

I think that Noah's "what is it?"  question very nicely captures the path
forward from here.  We make progress by slicing the meaning of our
communications finely and working out the common parts.  Just read
his question backwards and you see our progress: its UTF8, ok; its
XML, ok; its SOAP, ok; its ...hmmm...now we need work.

If at this point we cut over and say that no agreements are made
about the layers above SOAP, then we stop making progress. To me
logical path forward does not involve MIME/IANA because that layer
only tells me what kind of message packaging handler to invoke.
It is a part of the stack before UTF8, so it should not be involved in
the meaning of SOAP message.  When I want to decide on the vocabulary,
then I want to be in the SOAP layer.  In that layer I want to add a
"RequestForMaterial",  some generic notion of an "Order", and on top
of that I want to add "OfferToExchangeValue", some generic notion of
purchase.  Then I have a central agreement on "purchase order" that
can be used by everyone, precisely because it is a central agreement.

Ok this does not get your purchase order app written for next Tuesday
I agree.

John.

At 01:34 PM 5/12/2003 -0400, noah_mendelsohn@us.ibm.com wrote:

>Not wanting to overcomplicate this, but I have felt for some time that the
>current MIME type system is way too limited to do what we may be about to
>ask of it.  For example, consider a purchase order in a SOAP envelope.
>Before we get to assigning it a type, let's ask what is it?   Well, in
>some fundamental sense, it's a purchase order.  Note that you can't find
>that out from the root QName.  Of course, it's equally fundamentally a
>SOAP message. And it's an XML document.  And it's, by the way, a UTF 8 or
>UTF-16 encoding of Unicode.  If it has a routing header it's also  a
>"routable message".
>
>I honestly view the natural semantics of these things as more of a "mixin"
>sort of model.  It seems to me that we keep trying to take little slices
>through this mixin space, and then we always find out we need something
>else.  I have no constructive suggestions for exactly what to do,
>organizationally or technically, except that I think it might be useful to
>step back and gather some requirements and use cases before inventing new
>mechanisms.
>
>I don't want to cross-post, but David you are welcome to relay this or
>point it out to the TAG if useful.  Both lists are public.  Thanks.
>
>------------------------------------------------------------------
>Noah Mendelsohn                              Voice: 1-617-693-4036
>IBM Corporation                                Fax: 1-617-693-8676
>One Rogers Street
>Cambridge, MA 02142
>------------------------------------------------------------------
>
>
>
>
>
>
>
>"David Orchard" <dorchard@bea.com>
>Sent by: xml-dist-app-request@w3.org
>05/10/2003 02:08 PM
>
>
>         To:     "'Mark Nottingham'" <mark.nottingham@bea.com>, "'Don Box'"
><dbox@microsoft.com>, "'John Kemp'" <john.kemp@earthlink.net>
>         cc:     "'Mark Baker'" <distobj@acm.org>, "'Xml-Dist-App@W3. Org'"
><xml-dist-app@w3.org>, (bcc: Noah Mendelsohn/Cambridge/IBM)
>         Subject:        RE: SOAP MIME Type
>
>
>
>Yeah, that darned TAG ought to solve some of these issues. :-)
>
><snip/>
> > That having been said, there's no regular way to turn a QName
> > into a URI
> > [1], which I think is what Don wants to do. So, in the
> > meantime, we could
> > do something like
> >  XML-Dialect: "http://example.com/foo.xsd"; localname="Bar"
> > making the localname parameter optional, so that we can drop
> > it once the
> > QName mapping issue is solved to everyone's satisfaction.
> >
> > This also has bearing on TAG issue 9 [2], and should be
> > considered in that
> > context.
> >
> > 1. http://www.w3.org/2001/tag/ilist#rdfmsQnameUriMapping-6
> > 2. http://www.w3.org/2001/tag/ilist#uriMediaType-9
>
>Cheers,
>Dave

______________________________________________________
John J. Barton          email:  John_Barton@hpl.hp.com
http://www.hpl.hp.com/personal/John_Barton/index.htm
MS 1U-17  Hewlett-Packard Labs
1501 Page Mill Road              phone: (650)-236-2888
Palo Alto CA  94304-1126         FAX:   (650)-857-5100
Received on Monday, 12 May 2003 14:59:19 GMT

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