lustratus LiteBytes

Sometimes I get tired of being the guy in front of the train waving my flag and hoping I can stop or divert it.

I get called old-fashioned, blinkered, boring, misguided and a whole range of other names not suitable for printing here – but at the risk of getting another postbag of objections, I want to raise my flag again with respect to WOA (Web-oriented architecture).

I read Dion Hinchcliffe’s excellent article on WOA, discussing whether WOA was the future for SOA. The argument was essentially that SOA has not delivered the expected benefits, but WOA can. Essentially, WOA is all about arranging information in terms of resources that are accessed through HTTP in the same way as URLs. You have GET, PUT, POST and DELETE commands just like in most message-based SOA solutions. The resources are manipulated by components such as browsers etc, and it is the responsibility of the component to understand the representation and state changes of the information.

I have no problem at all with this – sounds great. My problem is the suggestion that this is the future of SOA – the implication that in some way SOA has failed and WOA, close cousin that it is, is the natural evolution. I have a couple of major grumbles here.

Perhaps the biggest is that WOA is all about a connectivity / integration architecture – a technical network really. The fundamental change with SOA from what people have done before is that SOA services are on business boundaries, not technical ones. Hence a SOA service is something that makes sense in business operations terms – eg Get Customer Details. Perhaps the implication is that in WOA the resources are also synonymous to business ops, but then how are they defined when the responsibility for understanding their representation and behaviour lies exclusively with the browser or other component accessing them?

Another particular gripe I have is that whereas SOA is based on a messaging bus to do the transfers, such as an ESB or a reliable messaging pipe like WebSphereMQ, in WOA all comms are done using HTTP, presumably with reliable delivery being provided through WSReliableMessaging ha ha. In fact, doing once and only once delivery of messages is really hard, and as we all know from the number of times we receive duplicate emails or none at all, HTTP is not brilliant at it. As for WSRM, as is often the case with standards developed to try to counter a dominant market de jure standard, the lowest common denominator approach required to get agreement across a range of parties renders the standard very questionable in terms of maturity.

Apart from that, I applaud WOA. As an analyst I am always delighted to see a new idea come to fruition, particularly with a new buzz word that has to be explained. After all, that is how analysts makes their businesses work! And to be serious, I see real value in WOA – but if people start looking at it as a replacement for SOA then I think users are in for a shock.

Steve