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Re: What does WSDL describe?

From: Mark Baker <distobj@acm.org>
Date: Sun, 26 Oct 2003 21:36:46 -0500
To: Savas Parastatidis <Savas.Parastatidis@newcastle.ac.uk>
Cc: www-ws-desc@w3.org
Message-ID: <20031026213646.N9730@www.markbaker.ca>

On Mon, Oct 27, 2003 at 02:03:38AM -0000, Savas Parastatidis wrote:
> <while-trying-to-avoid-another-REST-vs-WS-discussion>

Yah, me too.  I'm just in "explain state transfer and REST" mode.  I'm
not trying to bash other styles.

> I am only describing the exchange of messages and that we can do without
> the concept of an operation.

Sort of, I'd say ...

You claim there's no operation, but there really is one, because there
remains a notion of "success" and "failure".  You just have to ask
"success and failure of what?".  The answer to that question is your
operation, whether or not you choose to include it in your message.

I think it's useful to make the operation explicit rather than implicit
though; it's more extensible.  Otherwise you end up with an implicit
operation per IP port.  i.e. sending data to port X might be defined to
mean "process this data", while sending data to port Y might be defined
to mean "store this data".  Better to just make the operation explicit
and bind to a single port, the way the Web does with HTTP on port 80.

So it's true that you can get a whole lot done with just the "process
this state" implicit operation in your example - heck, EDI was built
around that operation (AFAICT).  But at least one more would be nice;
an operation for *retrieving* the state of things.

> It's the conceptual model for web services
> that I am talking about and its no-relationship to RPC, procedures,
> objects with methods, etc.

Sure.  That's what I've been talking about for the past four years or
so while criticizing SOA.

> All these within the concepts of WSA where
> you have the additional protocols for adding extra functionality, the
> communication protocol independence, modularity, etc.

Sorry, I don't understand what you mean there.

Mark.
-- 
Mark Baker.   Ottawa, Ontario, CANADA.        http://www.markbaker.ca
Received on Sunday, 26 October 2003 21:38:06 GMT

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