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Re: Choreography and the Semantic Web

From: Christopher B Ferris <chrisfer@us.ibm.com>
Date: Mon, 12 Aug 2002 10:40:58 -0400
To: Mark Baker <distobj@acm.org>
Cc: www-ws-arch@w3.org
Message-ID: <OFC610E06E.E317672C-ON85256C13.00482135-85256C13.0050939F@rchland.ibm.com>

Please see below.


Christopher Ferris
Architect, Emerging e-business Industry Architecture
email: chrisfer@us.ibm.com
phone: +1 508 234 3624

Mark Baker <distobj@acm.org> wrote on 08/11/2002 03:11:35 PM:

> A machine processable version of a form should work the same way.  The
> difference is that there's no human to punt to, so the server has to
> declare the type of document that it wants in return, rather than
> expecting a user to infer the type.  For example, it should say "send
> me a description of a person" (where "description of a person" is an
> RDF type identified by a URI), instead of "send me data", where the
> type of data is expressed only in a human-processable manner.

Huh? I don't understand your point here. Are you implying that WSDL
can only say "send me data"? 

> The main difference between this approach and WSDL is that WSDL
> focuses on operations *and* data types, whereas the REST approach
> focuses on just data types, and fixes the operation.  Another way to
> look at that, is that receiving some WSDL lists the methods, but it
> doesn't tell you which method to invoke, meaning that the agent is
> expected to know that a priori.  Or as Paul has said, WSDL is
> principally a design-time artifact, not a runtime one like a form.

Right. The key point of the phrase being 'design time'. Personally,
I think that design-time and runtime aspects of WSDL should be more 
delineated and preferably separated, but that's another issue. The
key point is that, for many, it is the absence of design-time artifacts
that make it difficult to write software that replaces the human/user 

By providing a) an ability to standardize on semantic expression of a 
and b) the ability of a service to expose to the world "here's what I 
here's how you can interact with me" that can be used at design-time is an
important aspect currently missing from the Web.

> > HTML, by virtue of being a very general format for human consumption
> > (i.e. all resources can have an HTML representation), solved this
> > problem for humans because there came an expectation that if you said
> > "Accept: text/html", you'd get something for the vast majority of
> > resources.  What we need, is a similar format/model for machines, such
> > as RDF.
> > 
> > <cbf>
> > So, what I read into this is you are saying "throw out WSDL and SOAP
> > and use RDF instead". What's wrong with replacing the 
> > you suggest above with application/soap+xml and/or 
> > </cbf>
> SOAP and WSDL do very different things than RDF does.  SOAP and WSDL
> can't be used to express the state of any resource; you can't use them
> to say "the temperature is 33 degress celsius", for example.


> I think that should answer Mike's question too.
> MB
> -- 
> Mark Baker, CTO, Idokorro Mobile (formerly Planetfred)
> Ottawa, Ontario, CANADA.               distobj@acm.org
> http://www.markbaker.ca        http://www.idokorro.com
Received on Monday, 12 August 2002 10:42:37 UTC

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