R085 Is For Static Description of Endpoint URIs (aka Design Time)

Umit,

The notes in the thread [1] are long and contain several issues, so I'm 
starting a new thread to discuss the subject issue. Here is the text of 
R085 taken from [2]:

R085
The description language SHOULD allow describing Messages that include 
references (URIs) to typed referents, both values and Services. (From PP. 
Last discussed 11 April, 2002.)

I'll parse this.

"The description language" == WSDL

"SHOULD allow describing Messages that include references (URIs) to typed 
referents," == a Web service message may contain a URI, in which case WSDL 
should be able to describe the type of thing identified by the URI

"both values" == the URI could refer to a document, in which case we 
should be able to describe its data type, e.g. MIME type or  XSD

"and Services" == the URI could refer to a Web service, in which case we 
should be able to describe to its WSDL interface and binding

This requirement clearly states that the WSDL document should be able to 
describe the type of a Service refered to by a URI. This is static typing.

This requirement does NOT state that the Message should be 
self-describing, i.e. that by looking at the message instance that 
contains the URI we can also find the additional type information, i.e. 
WSDL interface and binding. That would be dynamic typing.

However, I agree that the dynamic case is important and hence 
WS-Addressing [3]. IMHO, it would make sense for the WG to address that 
case.

Note that we haven't really addressed the "values" part of R085. However, 
a URI to a document could be modelled as a simple Web service that had a 
retrive operation for the document, e.g. if the URI uses the http: schema 
then retrieve is mapped to GET.

[1] http://lists.w3.org/Archives/Public/www-ws-desc/2003Jun/0143.html 
[2] http://www.w3.org/TR/ws-desc-reqs/#messages
[3] http://www-106.ibm.com/developerworks/webservices/library/ws-add/

Arthur Ryman,
WebSphere Studio Development Lead,
Web Services, XML and Data Tools

phone: 905-413-3077, TL 969-3077
assistant: 905-413-2411, TL 969-2411
fax: 905-413-4920, TL 969-4920
intranet: http://w3.torolab.ibm.com/~ryman/