RE: [wsrm] WSDL for WSRM ??

[Paolo Romano <Paolo.Romano@dis.uniroma1.it>]

I think I am a bit confused about how the interaction between the rm processor
and the final web service  should be described in wsdl.

Let me try to explain why I am confused: In the ws-rm wsdl we will describe
(apart from the ws-rm header blocks) the supported MEPs. In WSDL 1.1 the choice
is only between one-way and request-response, since sollicit-response and
notification MEPs (operations in WSDL terminology) are not interoperably
supported (WS-I states they MUST not be used in practice).

Suppose we choose to allow only one-way operations. This means that messages and
acknolowdgements will be exchanged asynchronously, carried by 2 separate HTTP
POSTs requests in opposite directions, and that the HTTP responses in both
directions will just carry the HTTP response code 202/200 without any SOAP
message.

Now, WS-RM headers will be inserted in the header of (possibly already) existing
SOAP messages used to allow applications interaction. These services will
already have their own WSDL description, which defines the supported operations
(MEPs) by the service, choosing between one-way or request-response.

Suppose the original "unreliable" web service has some operations which support
only the (synchronous) request response  MEP.
The SOAP node including both the ws-rm layer and the final webservice at this
point disagrees with the WS-RM supported MEP. In other words, the ws-rm layer
will simply respond by sending the HTTP 202 code and closing the TCP connection.
Then the request will be forwarded to the above layer, which instead expects the
underlying connection to be still open, because it is designed to respond
synchronously. The service requestor as well will see its connection closed in
an unexpected way, that is, without any response from the remote application.

There must be something that I am missing...

How can in general the ws-rm layer and the above layers be coupled to guarantee
compatibility, since they both have distinct WSDL definitions of their own
supported MEPs.

May be the sending application should use the MEP described in the WSDL of the
final receiving application, and specify it to the WS-RM sender processor (let's
say as a parameter). The  WS-RM sender processor could insert the specific MEP
to be used in an apposite ws-rm header block which will determine the behavior
of the WS-RM receiver. If, for example, the one-way MEP is chosen then the
receiving WS-RM processor will send just a response code. If, on the other hand,
the req/response MEP is chosen then the receiving WS-RM processor will wait for
a response to be returned from the above layer (say the application)?

I hope somebody can enlighten me...

Paolo

Scott Werden <scottw@wrq.com> ha detto:

>
> Using two one-way MEPs for the exchange has the advantage that it will work
> for bindings to any transport. The problem is that the ACK message can never
> be bound to a port with a soap:address element since the adress comes from
> the original reliable message. I suppose we can leave the the port binding
> out for the ACK.
>
> Scott
>
> > -----Original Message-----
> > From: Tom Rutt [mailto:tom@coastin.com]
> > Sent: Wednesday, June 25, 2003 12:33 AM
> > To: Sunil Kunisetty
> > Cc: Mark D. Hansen; WSRM-TC (E-mail)
> > Subject: Re: [wsrm] WSDL for WSRM ??
> >
> >
> > Sunil Kunisetty wrote:
> >
> > > Hi Mark,
> > >
> > > I mentioned that I'm going to look into annotating WSDL with
> > > RM operations, not MEPs though. If that's what you meant, I haven't
> > > had a chance to look into that yet. We could work together if
> > > you are interested too.
> > >
> > > Scott & Venkat also mentioned that they would chime in too.
> > >
> > > -Sunil
> > >
> > >"Mark D. Hansen" wrote:
> > >
> > >
> > >
> > >>I recall from the face-to-face meeting that a few of the
> > members of this committee were going to work on WSDL for the
> > message exchange patterns being defined.  Has anything
> > happened with that?  I've been working on it a little bit and
> > would be happy to help out as well.
> > >>
> > >>Mark Hansen
> > >>bus: (888) 360-7285
> > >>fax:  (914) 723-8671
> > >>email: khookguy@yahoo.com
> > >>
> > >>You may leave a Technical Committee at any time by visiting
> http://www.oasis-open.org/apps/org/workgroup/wsrm/members/leave_workgroup.ph
> p
> >>
> >>
> >
> >
> >You may leave a Technical Committee at any time by visiting
> http://www.oasis-open.org/apps/org/workgroup/wsrm/members/leave_workgroup.ph
> p
> >
> >
> >
> One approach is to have oneway MEP for each direction of interchange.
> The headers
> are defined as parts, and are bound  in the wsdl to the soap header.
> The body is a part which is bound to the soap body in the WSDL.
>
> This is what the BEA spec does for WSDL for Reliable Messaging.
>
> Tom Rutt
>
> --
> ----------------------------------------------------
> Tom Rutt		email: tom@coastin.com; trutt@fsw.fujitsu.com
> Tel: +1 732 801 5744          Fax: +1 732 774 5133
>
>
>
>
>
>
> You may leave a Technical Committee at any time by visiting
> http://www.oasis-open.org/apps/org/workgroup/wsrm/members/leave_workgroup.ph
> p
>
> You may leave a Technical Committee at any time by visiting
http://www.oasis-open.org/apps/org/workgroup/wsrm/members/leave_workgroup.php
>
>




--
Paolo Romano