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RE: Firewall sample application and requirements

From: Champion, Mike <Mike.Champion@SoftwareAG-USA.com>
Date: Wed, 29 May 2002 11:00:35 -0400
Message-ID: <9A4FC925410C024792B85198DF1E97E403456543@usmsg03.sagus.com>
To: www-ws-arch@w3.org



> -----Original Message-----
> From: Mark Baker [mailto:distobj@acm.org]
> Sent: Wednesday, May 29, 2002 10:06 AM
> To: Champion, Mike
> Cc: www-ws-arch@w3.org
> Subject: Re: Firewall sample application and requirements

> As I see it, you and David seem to believe that while REST is useful for
> some things, that there are things (substantial things, that are worth
> worrying about) that Web services can do that can't be reasonably done
> within the constraints of REST.  Is that true?

That is my current working assumption, yes.  I personally would be happy to
be convinced that it is wrong, but you're not doing a great job of that :~)
But irrespective my personal philosophy, it's very clear that a LOT of
people in the industry find a compelling use case for things that apparently
do not fall within the constraints of REST, so to declare them out of scope
for the WSA at the requirements phase strikes me as a complete non-starter.
I suspect we'd lose about 3/4 of our participants if this were to happen,
because this WG would be seen as irrelevant to the problem it was chartered
to address!  

> 
> I want us to meet our charter directive, to integrate cleanly with Web
> architecture.

The Charter says all sorts of things, it's our job to turn that into
concrete requirements.  For example:

"The same way programmatic interfaces have been been available since the
early days of the World Wide Web via HTML forms, programs are now accessible
by exchanging XML data through an interface, e.g. by using SOAP Version 1.2,
the XML-based protocol produced by the XML Protocol Working Group. The
services provided by those programs are called Web services."  

That sounds an awful lot like what we're talking about here -- POSTing
messages that use a protocol based on SOAP 1.2.  SOAP 1.2 talks about
methods, so you can't plausibly argue that this is out of scope for the WSA.
One could plausibly argue that best practice is to not use the concept of a
"method" inside the data being POSTed, and we might well draft the
architecture document to adovate this best practice, but that's not under
discussion now. 

The Charter also says: 

"The Web services architecture will need to be cleanly integrated in the Web
architecture: Web services should be addressable resources, results of
operations which do not have side-effects should be cacheable, etc."

This leaves considerable room for discussion on what "addressable resources"
means -- are the "methods" themselves addressable, or is every legal
invocation of a method directly addressable?   Again, we're talking about
requirements now, not drafting language to describe best practices.
Arguments that the WSA should strongly favor REST will have to stand or fall
on their own merits at the appropriate time; they can't be won by
language-lawyering the Charter.

We've circled back to where we started (several times, I think), and it's
time to just vote on the draft requirements wording and get this behind us.
Received on Wednesday, 29 May 2002 11:01:11 GMT

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