Don Box on WS-Transfer:

Stage 3. Wow, I can model my entire universe using less verbs/operations than I have fingers on one hand.  Why would I ever author another WSDL portType?  

I was puzzled for a while; then I went to check the spec, which contains XSD like this:

  <xs:complexType name="AnyXmlOptionalType">
      <xs:sequence>        
           <xs:any minOccurs="0"/>      
      </xs:sequence>
  </xs:complexType>

  <xs:complexType name="AnyXmlType">
      <xs:sequence>       
           <xs:any minOccurs="1"/>      
      </xs:sequence>    
  </xs:complexType>

And here’s the WSDL for the Resource portType:

  <wsdl:portType name="Resource">   
      <wsdl:documentation>        
          This port type defines a resource that may be read, written, and deleted.
      </wsdl:documentation>
      <wsdl:operation name="Get">
          <wsdl:input message="tns:Empty"/>
          <wsdl:output message="tns:AnyXml"/>
      </wsdl:operation>
      <wsdl:operation name="Put">
          <wsdl:input message="tns:AnyXml"/>
          <wsdl:output message="tns:OptionalXml"/>
      </wsdl:operation>
      <wsdl:operation name="Delete">
          <wsdl:input message="tns:Empty"/>
          <wsdl:output message="tns:Empty"/>
      </wsdl:operation>
  </wsdl:portType>

I wasn’t even aware that there was a standard portType in that spec before - now I can’t help but wonder what, exactly, this WSDL buys me. I had hoped that in contrast to the default REST model, WS-Transfer would enhance the uniform API idea by restricting resource representations to those that conform to a meaningful schema …

I can’t help feeling that this is a significant departure of former mainstream WS-* thinking; essentially, it looks like we’re supposed to finally get around WSDL tools features with close ties to XML Schema by no longer really using them.

Which, IMO, is a Good Thing™.