W3C home > Mailing lists > Public > public-ws-chor@w3.org > February 2004

RE: WSDL and pub/sub

From: Paul Denning <pauld@mitre.org>
Date: Thu, 12 Feb 2004 13:31:02 -0500
Message-Id: <6.0.0.22.0.20040212132946.01d74e68@localhost>
To: WS Choreography <public-ws-chor@w3.org>

See WS-Notification

http://xml.coverpages.org/ni2004-01-20-a.html

Paul

At 01:22 PM 2004-02-12, Burdett, David wrote:

>Steve
>
>Giving this a bit of thought makes me think that the essence of pub-sub is 
>...
>
>1. The publisher sets up a service that accepts subscriptions requests and 
>changes for some other service that actually publishes documents/messages.
>
>2. The subscriber then requests subscription to a service by sending a 
>messge which then gets either accepted or rejected.
>
>3. When the subscriber makes the request, they must include some kind of 
>"delivery address" that identifies where documents/messages etc, generated 
>by the publisher must be sent
>
>4. If the request is accepted, then the publisher will return some kind of 
>"identifier" for the subscription that can later be used when changing or 
>cancelling the subscription
>
>5. The publisher starts publishing documents. This is a one-way message 
>although it might be delivered reliably
>6. The publisher continues publishing documents until: a) the subscription 
>is cancelled, or b) the subscription runs-out, e.g. a certain period of 
>time has passed, a specific number of messages/documents have been 
>received, the subscriber hasn't paid.
>
> From a CDL perspective, the "delivery address" is what the Overview Model 
> calls a "Channel". This means that to use it, we need to have a way of 
> representing the Channel in XML and decie how it should be included in 
> the message. My thoughts would be the body.
>
>The rest sounds to me like a pretty regular Choreography Definition with 
>dependencies, e.g. you can't cancel a subscription unless you managed to 
>subscribe to it successfully.
>
>Another question is should such a Pub-Sub Choreography be standardized as 
>I am sure the need for Pub-Sub goes beyond WS Chor. For example you could 
>imagine a definition that allowed you to manage a subscription to any web 
>service then later cancel it. However you would need standard XML docs to 
>be used as Message Content for the Interactions in the Pub Sub.
>
>Also where should such a spec be developed ... by WSDL, by WS Chor? I'm 
>not sure I know the answer to that one.
>
>David
>
>
>-----Original Message-----
>From: Steve Ross-Talbot 
>[<mailto:steve@enigmatec.net>mailto:steve@enigmatec.net]
>Sent: Thursday, February 12, 2004 5:41 AM
>To: WS Choreography
>Subject: Fwd: WSDL and pub/sub
>
>
>How does this leave our stuff wrt the Barros usecase?
>
>Cheers
>
>Steve T
>
>Begin forwarded message:
>
> > From: "Jonathan Marsh" <jmarsh@microsoft.com>
> > Date: 11 February 2004 20:44:41 GMT
> > To: "Steve Ross-Talbot" <steve@enigmatec.net>
> > Subject: RE: WSDL and pub/sub
> >
> > WSDL 2.0 part 3 [1] describes some message exchange patterns that can
> > be
> > used as part of a pub/sub solution.  Look at all the "out-*" patterns
> > starting at section 3.4.  A complete pub/sub solution is not provided,
> > as the address and mechanics of "sub"ing and providing the address for
> > the "pub" to be delivered are not standardized in WSDL (perhaps this is
> > an orchestration problem?).  Note that the HTTP and SOAP bindings don't
> > support these message exchange patterns yet, but we have an issue open
> > on whether we should rectify this.
> >
> > Hope this helps.
> >
> > [1]
> > 
> <http://dev.w3.org/cvsweb/~checkout~/2002/ws/desc/wsdl20/wsdl20->http://dev.w3.org/cvsweb/~checkout~/2002/ws/desc/wsdl20/wsdl20- 
>
> > patterns.
> > html#out-only
> >
> >> -----Original Message-----
> >> From: Steve Ross-Talbot 
> [<mailto:steve@enigmatec.net>mailto:steve@enigmatec.net]
> >> Sent: Tuesday, February 10, 2004 10:07 AM
> >> To: Jonathan Marsh
> >> Subject: WSDL and pub/sub
> >>
> >> Jonathan,
> >>
> >> I seem to recollect that you indiciated that WSDL2.0 includes an MEP
> > or
> >> some such facility to represent pub/sub as a means of communication.
> >> Could you verify this? And could you point me to the appropriate
> >> description? This is something that the Choreography WG would very
> > much
> >>   like to have so that a single message could be sent to multiple
> >> sources without needing to bind to those sources.
> >>
> >>
> >> Best Regards
> >>
> >> Steve Ross-Talbot
> >> co-Chair W3C Web Services Choreography
> >>
> >> O: +44 207 397 8207
> >> C: +44 7855 268 848
> >> www.enigmatec.net
Received on Thursday, 12 February 2004 13:31:00 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Saturday, 18 December 2010 01:00:51 GMT