|Mittwoch, 15. Januar 2003|
Fujitsu, along with Sun, NEC, Oracle and Sonic Software published a proposal for reliable messaging with SOAP. I assume this has been reported all over blogland already, but I am a bit "connection challenged" right now since I've been on the road, so I couldn't really do much blog reading. I've had time to look at this spec offline, though, and I think it is indeed interesting -- because it is so familiar.
Comparing WS-Reliability to the 2 year old BizTalk Framework 2.0, which first defined the reliability mechanism also known as SRMP -- SOAP Reliable Messaging Protocol, shows that there's unfortunately very little new to see in WS-Reliability, with the notable exception of ordered delivery of message sequences through the use of unique message identifiers. What's also interesting -- and doesn't really make me happy -- is that we're seeing the invention of yet another message header with message-id. WS-Routing, for instance, already defines one and I don't get why there needs to be yet another header to establish message identity with WS-Routing being around for such a long time already. I would think that reliable messaging is something that doesn't really work without a solid understanding of where to send a message, so it certainly could and probably should pick up that header instead of defining its own.
A bigger problem is, though, that WS-Reliability carries forward quite a few shortcomings of the BizTalk Framework and introduces a whole set of new problems due to the spec's choice of language.
What I find also very noteworthy is that the authors say that they have yet to address synchronization between sender and receiver and establishing a common understanding by sender and receiver about whether the message was properly delivered (meaning that the send/ack cycle was fully completed). I assume that once they do so, they'll throw the synchronous, piggybacked reply on top of HTTP out of the window, because this creates an in-doubt situation for the acknowledging party.
12:33:36 AM comments