RE: XML Schema comment on WSDL 2.0

Thank you for your comment - we tracked this as a Last Call comment LC90
[1].  Though we investigates solutions to this problem, the vendors
represented in the Working Group did not express any interest in
providing implementation support during our CR period, even if we
defined such functionality as an extension (for which we developed an
existence proof [2]) within our Recommendation.  Accordingly we were
forced to close this issue without action.

 

If we don't hear otherwise within two weeks, we will assume this
satisfies your concern.

 

[1] http://www.w3.org/2002/ws/desc/4/lc-issues/issues.html#LC90

[2] http://lists.w3.org/Archives/Public/www-ws-desc/2005May/0042.html

 

 

________________________________

From: public-ws-desc-comments-request@w3.org
[mailto:public-ws-desc-comments-request@w3.org] On Behalf Of Biron,Paul
V
Sent: Wednesday, November 24, 2004 2:27 PM
To: 'public-ws-desc-comments@w3.org'
Cc: W3C XML Schema IG
Subject: XML Schema comment on WSDL 2.0

 

The following is a comment on the WSDL 2.0 last call [1] from the XML
Schema WG.  We very much appologize about the lateness of this comment.

Paul Biron, for the XML Schema WG 
[1] http://www.w3.org/TR/2004/WD-wsdl20-20040803 

Problem statement 

It is not uncommon for schema designers to architect systems with
multiple schemas for a single namespace, with different defintions of
identically (Q)named schema components (elements, types, etc.).  A WSDL
description currently allows only a single schema (in <wsdl:types>) and
thus a single set of type components available for reference (e.g., in
<wsdl:input>, <wsdl:output> and <wsdl:fault>).  Therefore, WSDL is not
currently able to describe a service where input and output share the
same namespace but use conflicting schemas.

Use cases 

1. The prototypical case of multiple schemas for a single namespace is
XHTML.  All flavors of XHTML share the same namespace but there are
three separate (and conflicting) schemas: strict, transitional and
frameset.  It is not currently possible to use WSDL to describe a
service that takes XHTML transitional documents as input and output's an
equivalent XHTML strict document.

2. Another case of multiple schemas for a single namespace arises from
the common strategy of versioning a vocabulary by keeping the namespace
constant and indicating the vocabular version as part of the document
content (e.g., with a @version attribute, etc.).  XSLT is the
prototypical case of this versioning strategy.  It is not currently
possible to use WSDL to describe a service that takes an XSLT 1.0
stylesheet as input and outputing an similar XSLT 2.0 stylesheet (and
vice versa).

3. Other cases of multiple schemas for a single namespace arise for any
number of reasons, and the particular reasons why people have
architected their vocabularies so as to have multiple schemas all
sharing the same namespace are what really matters here.  What does
matter is that people are doing this and that all of these cases have
one thing in common: that WSDL as it stands cannot be used to describe
interactions where there is ANY conflict between the different input and
output schemas for the same namespace.

Proposed solution 

A possible solution to the above problem would be to provide a means of
partitioning <wsdl:types> into a) input; b) output; c) fault and d)
(possibly) "all" sections.  Declarations within <wsdl:input> could
reference only those components in the "input" partition (or the "all"
partition if that were allowed); declarations within <wsdl:output> could
reference only those components in the "output" partition, etc.  Another
more general solution might be to

allow an arbitrary number of "labled" partitions (or, more correctly,
schemas) 
which could then be referenced by any component in the WSDL description.


The XML Schema WG considers this issue important but realizes that it is
late in your rec-cycle.  We hope you will consider the issue carefully
and perhaps together we can arrive at a solution that works for
everyone.