[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]
Subject: RE: [sca-bindings] ISSUE 2 - Callback support over the Web Service binding
Hi Michael, I have already raised it in the assembly. Java and C++ would share exactly the same problem , and the assembly has wording about dynamic callbacks.... Best Regards Peter -----Original Message----- From: Michael Rowley [mailto:mrowley@bea.com] Sent: Thursday, 4. October 2007 17:34 To: Peshev, Peter; Simon Nash; sca-bindings@lists.oasis-open.org Subject: RE: [sca-bindings] ISSUE 2 - Callback support over the Web Service binding Peter, I believe this should be an issue for SCA-J. Could you raise it there? Michael -----Original Message----- From: Peshev, Peter [mailto:peter.peshev@sap.com] Sent: Wednesday, October 03, 2007 3:40 AM To: Simon Nash; sca-bindings@lists.oasis-open.org Subject: RE: [sca-bindings] ISSUE 2 - Callback support over the Web Service binding Hi When speaking about redirecting the callback, by API it is possible to redirect it to another component, whose services could be lacking binding.ws and instead having only some other binding /*let's say binding.jms due to the current lack of other bindings in the OASIS TC :) */. If that should be a supported scenario (outbound one binding, inbound another) that looks that the callbackId-s should be something SCA specific, and hardly rely on some WS-standard. I am little bit confused in which TC (java, assembly, bindings) that should be addressed. Any thoughts / comments? Btw, I personally dislike refirecting the callback since that is actually dynamic appearance of wires (invocation paths) via java code usage. That introduces hidden dependencies among components, which cannot be analyzed and displayed by any tooling (except some heuristic code parsing), cannot be overridden by the assembler via SCDL files and somewhat hinders the main focus of component reuse and SOA. In addition such dynamic redirecting is likely to complicate any implementation which spans beyond one JVM. Best Regards Peter -----Original Message----- From: Simon Nash [mailto:NASH@uk.ibm.com] Sent: Tuesday, 2. October 2007 13:51 To: sca-bindings@lists.oasis-open.org Subject: Re: [sca-bindings] ISSUE 2 - Callback support over the Web Service binding Using the wsa:ReplyTo header for the callback endpoint does not seem to exactly match SCA callback semantics, which allow callback messages to be directed to a different endpoint from the endpoint that receives the reply to the original request (by calling setCallbackObject() with a ServiceReference). Using wsa:ReplyTo also requires a message ID to be added to the original request and the same message ID to be returned on the reply and any callbacks in the wsa:RelatesTo header. This is more of an observation than a problem, though it does require extra state to be maintained for the message IDs being exchanged. In Tuscany, we did not use wsa:Reply To. Instead we used the WS-Addressing wsa:To endpoint reference with reference parameters to represent the callback endpoint (as a wsa:EndpointReference), the callback ID, and the conversation ID for stateful callbacks. I did not propose a specific solution when opening this issue because I wanted to open this up to as many suggestions and options as possible. The discussion around wsa:ReplyTo has been interesting. Perhaps someone will have an idea on we can overcome the semantic mismatch that I mentioned above. I agree that defining a new header for SCA callbacks would be undesirable. Even the use of SCA-specific reference parameters seems less than ideal, but without them I'm not sure how additional information like the callback ID could be transmitted. We can't use wsa:MessageID for this, because of the statement in the WS-Addressing spec that "No two messages with a distinct application intent may share a [message id] property." Perhaps the callback ID could be mapped into a wsa:MessageID by adding a unique discriminator, so different callback requests could use distinct message IDs from which the same callback ID could be extracted. Simon Simon C. Nash, IBM Distinguished Engineer Member of the IBM Academy of Technology Tel. +44-1962-815156 Fax +44-1962-818999 Khanderao Kand <khanderao.kand@oracle.com> 01/10/2007 22:47 To Michael Rowley <mrowley@bea.com> cc sca-bindings@lists.oasis-open.org Subject Re: [sca-bindings] ISSUE 2 - Callback support over the Web Service binding Michael Rowley wrote: > One problem with using WS-Addressing wsa:ReplyTo is that it is usually > used to send the response message of a request/response pair. I don't > think that WS-Address forbids its use for subsequent messages > (callbacks), but it would at least be unconventional. > [khanderao] IMHO WS-Addressing does not make any assumptions on the number of returned messages. It is upto the integration scenario to have one or many. > However, if we can't use wsa:ReplyTo, that would seem to imply that we > have to devise our own header to use, but that would be getting > dangerously close to inventing a wire-level protocol, which we don't > want to be doing. > [khanderao] Introducing SCA specific correlation / replyTo parameters would not be essential. As far as possible we should be using the available standards, like WSA / WS-Coordination etc.. > Michael > > -----Original Message----- > From: Eric Johnson [mailto:eric@tibco.com] > Sent: Monday, October 01, 2007 12:16 PM > To: sca-bindings@lists.oasis-open.org > Subject: Re: [sca-bindings] NEW ISSUE: Callback support over the Web > Service binding > > Created as: http://www.osoa.org/jira/browse/BINDINGS-2 > > -Eric. > > Simon Nash wrote: > >> TARGET: >> >> Web Service Binding specification, section TBD >> >> DESCRIPTION: >> >> The Web Service binding provides no example or suggestion for how SCA >> callback semantics could be carried over Web services. There is an >> example in section 2.2.3 for how conversation semantics could be >> supported. It would be good to give some guidance (somewhere in the >> > range > >> between example and normative) for what could be done for callbacks. >> > One > >> possibility is to make use of the capabilities provided by >> > WS-Addressing. > >> PROPOSAL: >> >> None yet. >> >> >> >> >> >> >> Unless stated otherwise above: >> IBM United Kingdom Limited - Registered in England and Wales with >> > number > >> 741598. >> Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 >> > 3AU > >> >> >> >> >> >> Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]