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RE: Rationale for Dropping the <soap:body use=...> Attribute

From: Martin Gudgin <mgudgin@microsoft.com>
Date: Wed, 25 Sep 2002 13:18:34 -0700
Message-ID: <92456F6B84D1324C943905BEEAE0278E02A9FFC8@RED-MSG-10.redmond.corp.microsoft.com>
To: "Anne Thomas Manes" <anne@manes.net>, "Jacek Kopecky" <jacek@systinet.com>, <ryman@ca.ibm.com>
Cc: "WS Description WG" <www-ws-desc@w3.org>

Anne, 

I don't think reducing scope was the main reason. A awful lot of interop
problems are attributable to SOAP Encoding in SOAP 1.1 and/or
use='encoded' in WSDL 1.1

The WS-I BP WG was satisfied that use='encoded' was unnecessary. And we
are not just making a recommendation that you SHOULD say use='literal',
we are saying you MUST say use='literal'.

Martin


> -----Original Message-----
> From: Anne Thomas Manes [mailto:anne@manes.net] 
> Sent: 19 September 2002 06:31
> To: Jacek Kopecky; ryman@ca.ibm.com
> Cc: WS Description WG
> Subject: RE: Rationale for Dropping the <soap:body use=...> Attribute
> 
> 
> 
> One more point:
> 
> WS-I has chosen to not include Encoded in the Basic profile. 
> That isn't quite the same thing as saying that they have made 
> the recommendation to use only Literal. This was a hefty 
> topic of debate, and one of the primary reasons why they 
> decided not to include Encoded was to reduce the scope of the 
> Basic profile.
> 
> Anne
> 
> > -----Original Message-----
> > From: www-ws-desc-request@w3.org 
> [mailto:www-ws-desc-request@w3.org]On
> > Behalf Of Jacek Kopecky
> > Sent: Thursday, September 19, 2002 8:07 AM
> > To: ryman@ca.ibm.com
> > Cc: WS Description WG
> > Subject: Re: Rationale for Dropping the <soap:body use=...> 
> Attribute
> >
> >
> >
> >  Arthur,
> >  just two points:
> >
> >  1. By constraining oneself to XML Schema as the abstract 
> type system, 
> > one constrains oneself to the tree data model inherent in 
> XML Schema, 
> > other data models being out of reach (describing other data 
> models in 
> > XML Schema is at best a kludge). For example - what if I want to 
> > transfer some specific RDF data in a service? How do I describe the 
> > service using only XML Schema?  It is true that the real 
> > representation need not be XML, but this is an orthogonal topic.
> >
> >  2. WS-I doesn't seem to support SOAP Encoding in their activities, 
> > and if I understand you correctly, they are in fact 
> creating their own 
> > graph encoding. It is understandable for them, but I don't 
> think it is 
> > possible for WSDL 1.2 not to support SOAP Encoding properly, since 
> > SOAP Encoding is part of SOAP 1.2 - the product of a peer 
> W3C Working 
> > Group - and the WS-Desc WG has sent no comments against 
> SOAP Encoding 
> > in the Last Call phase.
> >
> >                    Jacek Kopecky
> >
> >                    Senior Architect, Systinet Corporation
> >                    http://www.systinet.com/
> >
> >
> >
> > On Wed, 2002-09-18 at 19:35, ryman@ca.ibm.com wrote:
> > >
> > > Jacek,
> > >
> > > I think it's useful to seperate the discussion into two parts:
> > >
> > > 1) abstract (binding neutral) definition of messages in WSDL
> > > 2) format of messages in the SOAP binding
> > >
> > > Concerning 1) I am in favour of just using XML schema. In fact, 
> > > there is also discussion that the <message> element be 
> removed and 
> > > that
> > messages be
> > > directly defined using schema, i.e. without <part>s. Allowing 
> > > different schema languages is a step in the opposite direction.
> > >
> > > Concerning 2) the WS-I.org recommendation is to just use literal. 
> > > Also, WS-I.org is working on an algorithm to encode 
> graphs in a way
> > that can be
> > > described using a literal schema. So if the concrete message
> > format is XML,
> > > then I see little benefit in allowing the concrete schema to be
> > different
> > > than the abstract schema. However, there are important 
> cases where 
> > > the concrete message format is not XML. For example, in 
> HTTP GET the 
> > > input parameters are url encoded. (e.g. the input gets encoded as
> > symbol=IBM and
> > > not as <symbol>IBM</symbol>). Also, if the message 
> includes binary 
> > > resources, then we can describe them abstractly as some 
> restriction 
> > > of xsd:hexBinary, but the concrete message format could be a MIME
> > type such as
> > > image/jpeg using SOAP with attachments.
> > >
> > > To summarize:
> > > - First, we should view the message definition as 
> abstract and use 
> > > XML Schema as the abstract data type language. This establishes a 
> > > proper layering in WSDL by isolating the message 
> definition from the 
> > > bindings. -Second, we should define the concrete message 
> format in 
> > > the binding. -Third, evidence from WS-I.org tells us that for the 
> > > SOAP
> > binding, we can
> > > live with literal only for concrete XML messages.
> > > -Fourth, using literal only doesn't mean that the 
> abstract message 
> > > definition is always concrete since there are other important 
> > > non-XML formats such as url encoding and MIME.
> > >
> > > Arthur Ryman
> > >
> > >
> > >
> >
> >
> > >                       Jacek Kopecky
> >
> >
> > >                       <jacek@systinet.c        To:       Arthur
> > Ryman/Toronto/IBM@IBMCA
> >
> > >                       om>                      cc:       WS
> > Description WG <www-ws-desc@w3.org>
> >
> > >                                                Subject:  Re:
> > Rationale for Dropping the <soap:body use=...> Attribute
> >
> > >                       09/18/2002 12:11
> >
> >
> > >                       PM
> >
> >
> > >
> >
> >
> > >
> >
> >
> > >
> > >
> > >
> > >  Arhur,
> > >  if you want an abstract schema at the wsdl:message 
> level, that's OK 
> > > with me and it's understandable. On the other hand, if 
> you want to 
> > > remove the use attribute by saying that "literal XML 
> Schema" is the 
> > > only possible way in SOAP, I disagree because that either 
> results in 
> > > ugly
> > > *and* ambiguous data structure schemata or in disallowing 
> other data
> > > models altogether (with SOAP Data Model among them).
> > >  I think that especially because the parts of 
> wsdl:message should be
> > > described abstractly, we may need different data models 
> right here,
> > > otherwise we'll say that, abstractly, WSDL only describes 
> services that
> > > can transfer trees with very raw untyped references.
> > >  So, either let's keep use="encoded" or let's allow 
> different schema
> > > languages (other than XML Schema), and I prefer the 
> latter because it
> > > agrees with the requirement "abstract description of wsdl:message
> > > parts".
> > >  Best regards,
> > >
> > >                    Jacek Kopecky
> > >
> > >                    Senior Architect, Systinet Corporation
> > >                    http://www.systinet.com/
> > >
> > >
> > >
> > >
> >
> >
> 
> 
Received on Wednesday, 25 September 2002 16:20:11 GMT

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