Forum OpenACS Development: Re: Best-in-class interoperability?

Posted by Andrew Grumet on
they struck me as possible examples of ways in which the
OACS/dotLRN community could extend its competitive edge
in web services and, in doing so, mitigate the liability
of the relatively unknown technology stack.

I can't speak to the JSR, but historically OKI has taken a dim view of XML over HTTP. I've sat in meetings with the architects of the OSIDs in which they're referred to Web Services as an "implementation detail". Again, historically, they've very calculatedly specified things at the level of the technology stack. Here's the test: if you have a method call that returns and object that itself has method calls, and that is opaque (i.e. can't be expressed in terms of simple strings, numbers, booleans, etc) then the spec will not lend itself well to cross-platform interoperability.

The XOSIDs are interesting because now lots of different technology-stack-dependent implementations can be built. From the article Dave B. linked to...

"Note that implementing an OSID in such a language doesn't mean that it will then be interoperable with OSID adapters that have been written in other languages."

That is, you can now build an island of compatibility for each stack. The best comparison may be drawn to something we have already: our ACS Service Contracts paradigm, and the set of contracts that have been defined and their implementations.

But...the linked article also hints...

"Which of course raises the older question of how OSIDs relate to Web Services in practice. Part of the answer will be demonstrated at alt-i-lab in Sheffield..."

Maybe they've found an interesting way to transform the XOSIDs to WSDL. Doing this would would be expensive and something of a "dirty trick" for a number of reasons (would require DCOM-like architecture, which the SOAP guys were pointedly trying to get away from), but it would be interesting if they did it this way and were able to pull it off.

Of course all this isn't to say that better interoperability through XML and HTTP isn't a good thing. The best opportunties seem to be in places with well specc'ed XML formats and protocols that are truly cross-platform, such as IMS CP (lors*) and IMS Enterprise (user sync) and RSS and XMLRPC. I'll believe it when I see it, but everything I've seen in three years of brushing up against OKI is that they are pretty deeply Web Services unfriendly.