There is nothing stopping a WS application returning a WSDL or even a BPEL fragment to indicate its next valid call. So the fixed-endpoints thing isn't a limiting thing of WS, it could be argued that in a goal oriented choreography that a more formal document exchange is liable to be more effective (e.g. vendor managed inventory) as it enables the async exchanges which implies some form of long term commitment to endpoints.
Steve 2008/8/31 Alan Dean <[EMAIL PROTECTED]>: > Michael, > > I think that, from the perspective of REST, the statement that the > participants "may not change the Internet locations of the end-points > (w/o breaking the contract)" is incorrect. > > Whilst this may well be true of WS-*, the uniform interface constraint > of REST means that the application state is surfaced via hypermedia - > not fixed endpoints. > > Regards, > Alan Dean > > On Sat, Aug 30, 2008 at 7:40 PM, Michael Poulin <[EMAIL PROTECTED]> wrote: >> I think Rob is right about "URI and HTTP verb semantics" (?) >> >> Now, if we get back to WS-CDL and its Global Contract, we end up with the >> contract for entire choreography with frozen set of URI/Ls. That is, the >> participants may not change the messages only but also may not change the >> Internet locations of the end-points (w/o breaking the contract) unless >> they >> start to operate with DNS aliases. Am I right? >> >> - Michael >> >> ----- Original Message ---- >> From: Rob Eamon <[EMAIL PROTECTED]> >> To: [email protected] >> Sent: Saturday, August 30, 2008 5:18:56 PM >> Subject: [service-orientated-architecture] Re: Distinction between >> "Choreography" and "Orchestration" >> >> I'm not a REST practitioner, but would this be covered via a >> combination of URI and HTTP verb semantics? URI would indicate the >> appropriate resource, eg. Order, Payment, etc. PUT/POST would "place >> order", "amend order" and "make payment" (I'm unclear on whether put >> or post would be appropriate here), DEL would cancel. >> >> Minimizing/eliminat ing the mixing of the verb/action into the >> document being exchanged would seem to be a good thing to strive for. >> >> -Rob >> >> --- In service-orientated- architecture@ yahoogroups. com, "Ashley at >> Metamaxim" <ashley.mcneile@ ...> wrote: >>> >>> To bring this whole thing back to the REST vs. SOAP issue: >>> >>> All the approaches to choreography that I have seen, including but >>> not limited to WS-CDL, require that the choreography integration >>> infrastructure be able to identify the messages exchanged between >>> the participants at the "business semantics" level: i.e., >>> that "Place Order", "Amend Order", "Cancel Order", "Make Payment" >>> etc. are distinguishable as such to the choreography management >>> mechanism. >>> >>> Does this mean that REST, whose messages conform to a standardised >>> vocabulary (GET, PUT, POST, DELETE) that does not expose the >>> messages' business semantics, is incompatible with choreography? >>> >>> Any thoughts on this? >>> >>> Rgds >>> Ashley >
