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Re: Proposal for Describing Web Services that Refer to Other Web Services: R085

From: Arthur Ryman <ryman@ca.ibm.com>
Date: Fri, 25 Apr 2003 15:02:57 -0400
To: "Amelia A. Lewis" <alewis@tibco.com>
Cc: Mark Baker <distobj@acm.org>, www-ws-desc@w3.org, www-ws-desc-request@w3.org
Message-ID: <OFC30DC026.B27C8D16-ON85256D13.00669A62@torolab.ibm.com>

Thx. I think you correctly conveyed the intent of the proposal.

I am personally a fan of URIs, but I don't think the WSD WG is in a 
position to dictate system architecture. The mission of the WG is to 
provide a technology that can be used to describe what people are doing. I 
think it is valid to design WSDL so that it is easy to describe Web 
services that conform to Web architecture, and possible to describe Web 
services that do not conform to Web architecture. That is why the proposal 
is to allow both xsd:anyURI and other domain specific complex types. If 
those complex types solve a real problem they will become standardized. If 
developers see the benefit of pure URI addressing then the complex types 
will fade away.

The WSDL spec at a minimum should require WSDL processors to understand 
xsd:anyURI. Organizations like WS-I can define profiles that augment the 
addressing scheme with other complex types if there is a demand. As long 
as WSDL enables that, we have done our job.

Arthur Ryman

"Amelia A. Lewis" <alewis@tibco.com>
Sent by: www-ws-desc-request@w3.org
04/25/2003 12:07 PM

        To:     Mark Baker <distobj@acm.org>
        cc:     www-ws-desc@w3.org
        Subject:        Re: Proposal for Describing Web Services that Refer to Other Web Services: 


On Fri, 25 Apr 2003 11:53:04 -0400
Mark Baker <distobj@acm.org> wrote:
> Look, I was *agreeing* with Amelia; there exist lots of services whose
> identifiers do not contain sufficient information to interact with the
> service.
> But for *all* of those systems, it is possible to design a URI scheme
> (perhaps more than one) such that all the necessary information *is*
> contained in the URIs (either by value or by reference to a standard,
> as I mentioned).

This, though, is where I think we part company.  While it is *possible*
to design such schemes, it is not always practical.  In particular, when
other means already exist and are preferred, efforts to promote a
URI-based syntax tend to stall, stagnate, and fail.

*Can* be != is.  Also != *should* be, in my opinion.

> I think I also mentioned that every successful large scale distributed
> system (that I've looked it anyhow, which is many) has this property.

Depends on what you mean.  If you mean that all successful large scale
distributed systems use URIs for addressing, I do not agree.  If you
mean that they all use standardized addressing, it almost goes without

This discussion started from a question of whether WSDL addressing
syntax ought to permit only URI, or ought to permit more complex address
definition types.  As Mike Champion pointed out, in order to work with
stuff that currently exists, some of which cannot be identified by URI,
provision ought to be made to permit more complex types.  This was the
point in Arthur Ryman's original proposal that I believe you originally
objected to.  I objected to your objection, on the grounds that while
URI *might* one day be universal, at present it is not.

Summary: to support services that are not URI-locatable, it should be
possible to use more complex addressing syntax, rather than restricting
address syntax to URI alone.

Amelia A. Lewis
Architect, TIBCO/Extensibility, Inc.
Received on Friday, 25 April 2003 15:03:11 UTC

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