comments on the wsdl 2.0 working drafts

Here's my thoughts on the working drafts.  In general its an improvement 
over WSDL 1.1 but I still feel a need for simplification. 

Web Services Description Language (WSDL) Version 2.0 Part 1: Core Language Operation Style

I think having the interface writer specify the applicable style on an 
interface or operation is a bad approach.  Is the interface writer aware 
of the possible styles that exist?  In addition the style is optional, so 
tools will still need to function in the absence of the style attribute. 
Furthermore, specifying the style of the interface blurs the line between 
interface and binding.  I think a better approach would involve supporting 
extensible interface/message structure constraints via the binding.  Using 
this approach, when the wsdl processor encountered a binding that 
referenced an interface it would utilize the constraints associated with 
the specific binding to validate interface.

2.3 Interface Fault

Why are fault messages considered 'reusable' but input / output messages 
are not?  This seems inconsistent. A major improvement over WSDL 1.1 is 
the removal of the top level 'message' components.  From my experience 
there's little benefit to specifying 'named' messages.  If these do exist 
why are they specified within an interface?  IMHO the complexities 
introduced by named messages outweigh any convenience of reuse. 

2.5.2 XML Representation of Message Reference Component

I don't see any use in the inclusion of a 'messageLabel' attribute.  Are 
there any examples where this is not redundant (deducible from the 
context)? I think the inclusion of optional attributes/elements in the 
spec that have no clear usefulness is terribly detrimental and one of the 
regrettable weaknesses of wsdl 1.1

2.9.2 XML Representation of Binding Component

Seems odd that the binding lacks infault and outfault.  I'd assume that 
the structures should be symmetric?  These sort of mysterious differences 
make the spec feel clumsy.

2.9 Binding

I'm struck the variety of places where we expect the wsdl author to 
specify binding related information.  An interface has a 'style' (though 
optional).  The binding has a 'type' then there are 'extensibility 
attributes' used to specify a soap protocol.  Then there are 
'extensibility elements' and of course this does not include possible use 
of 'features' and 'properties'.  IMHO there are too many mechanisms at 
play here.  I'd suggest returning to the simplicity of the wsdl 1.1 and 
its use of the extensibility element.  Here's a summary of the constructs 
I feel should be removed and how ...
The binding's type attribute.  This could be deduced by the namespace of 
the child extensibility element (e.g. wsdl 1.1).
The binding's style attribute.  Unneeded .... see comments above on
The binding's extensibility attributes.  Don't encourage their use.  Why 
not just utilize the attributes of the extensibility elements (e.g. wsdl 

Web Services Description Language (WSDL) Version 2.0 Part 3: Bindings

I don't see any description or examples of how to specify the content of a 
SOAP header?  Is the editor's copy incomplete ... I must confess I 
couldn't make much sense of it.  I think having examples included in the 
Primer would go a long way to making the design clearer.



Craig Salter
Rational Studio XML Web Services
Internet:     Notes: Craig Salter/Toronto/IBM@IBMCA

Received on Friday, 8 October 2004 09:11:16 UTC