Savas responds, noting he and his co-authors had previously patched that portion of their paper. Great. Here it is;

There have been proposals for naming and uniformly providing access to resources, such as the REpresentational State Transfer (REST) [24] model. However, since REST depends on HTTP (or more accurately a protocol with HTTP-like semantics) it is protocol specific and hence unsuitable for heterogeneous systems like the Grid. It also requires a particular interface to be used with the exposed resource, hence coupling identity and interface. In practical terms, this means that HTTP proxies must be placed in front of non-HTTP aware resources (e.g. FTP).

My first comment is that it appears contradictory; the last sentence talks about how other protocols can be supported, yet the previous paragraph still claims it’s protocol specific.

Another comment concerns the last sentence of the first paragraph; I think Savas probably got that from something I said to him, but I should elaborate. Identity and interface are coupled only in the sense that there’s a default association of URI scheme to protocol. But that association is not to the exclusion of other protocols. Consider an ftp URI; alone in the wild, that URI maps to, basically, the FTP RETR method. But one can use that same identifier in the context of any system whose interaction semantics can subsume those of FTP, for example, HTTP. I wish there were another example of systems that it could have been subsumed by, but I can’t think of one. And FWIW, what’s special about HTTP here is that, for *all* URIs, HTTP is an answer to the question “Name a protocol, other than the one suggested by the URI scheme, which can be used to interact with the resource identified by this URI”. That’s why HTTP is so special (and another explanation for why protocol independence is such a harmful concept).

Good stuff though. I’m really very encouraged by this work, and WS-RF too, as from my POV, both seem to be getting closer to the sweet spot of the Web as large scale integration solutions.


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