Re: Proposal for Describing Web Services that Refer to Other Web Services: R085

Sergey,

You are defining a dynamic binding discovery protocol, which is  beyond 
the scope of R085. Recall that R085 is a WSDL requirement. It states that 
a WSDL document must describe the endpoint. If you feel that dynamic 
discovery is important, then I suggest you submit this to the WG as a new 
requirement, and give a good motivating example. IMHO, I think it is 
useful to dynamically retrieve the WSDL associated with an endpoint, not 
just retrieve the binding.

I see a small problem with your proposed implementation. You say that the 
binding is obtained by performing a retrieval on the URI of the endpoint. 
However, you can't retrieve the URI unless you know the binding. You have 
to assume some binding, e.g. if the URI uses http: then do a GET (possibly 
with something appended to the URI, e.g. ?WSDL).

Arthur Ryman




"Sergey Beryozkin" <sberyozkin@zandar.com>
Sent by: www-ws-desc-request@w3.org
05/01/2003 11:48 AM

 
        To:     Arthur Ryman/Toronto/IBM@IBMCA
        cc:     <www-ws-desc@w3.org>
        Subject:        Re: Proposal for Describing Web Services that Refer to Other Web Services: 
R085

 


Hello,

I'd just like to return again to the question of whether dynamic bindings
should be disallowed by the proposal[1]or not. Proposal [1] says @binding
attribute is declared statically in the WSDL document, this probably 
covers
the majority of cases.

How practical/usefult would it be to add @binding optional attribute to 
the
endpoint reference definition :

<wsdl:endpoint name="partURI" part="return"
xpath="/p:Parts/Part/@xlink:href" interface="tns:partInterface"
binding="dynamic"/>

@binding attribute can have 2 values, "static" (default) and "dynamic". 
When
@binding is "dynamic", the runtime *may*, but has not to, try to retrieve 
a
binding definition from the newly created URI (perhaps with an extra
path/request parameter to indicate that it's not the representation which 
is
requested).
If dynamic binding discovery is not attempted/fails, a binding statically
referenced (as shown in [1]) will be used.
If dynamic binding is used then a wsdl doc is returned. This returned wsdl
must contain a binding for a given interface (probably identified the way
shown in [1]), and may/should also contain a <service> element. One issue
here is that the returned wsdl has to know about portTypes/interfaces
referenced in the original wsdl doc, and a such, these portTypes must be
grouped in a separate WSDL doc.

Thanks
Sergey Beryozkin

[1]
http://lists.w3.org/Archives/Public/www-ws-desc/2003Apr/att-0088/R085-2003-0
4-22.html