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Re: WSD Requirements: add a requirement about safe and idempotent characteristics

From: Mark Baker <distobj@acm.org>
Date: Tue, 26 Nov 2002 14:13:26 -0500
To: www-ws-arch@w3.org
Message-ID: <20021126141326.J16590@www.markbaker.ca>

Hi Hugo,

On Mon, Nov 25, 2002 at 04:52:35PM -0500, Hugo Haas wrote:
> I would therefore like to submit the following requirements to the
> 	The description language MUST be able to indicate the
> 	characteristics of an operation as a Web interaction. The
> 	description of a service MUST indicate whether an operation is
> 	safe. A service SHOULD be exposed as a Web method, in a
> 	similar way as the Web Method Specification Feature[2].
> Any comments?

I personally don't think this is necessary.  It's not enough for an
application to know that an operation is safe or idempotent, it has to
know what the operation *means*, and safety and idempotency are just
a small part of that meaning.  For example, the HTTP OPTIONS
operation/method is safe and idempotent, as is HTTP GET, but they mean
something very different.  Without the full meaning of the operation
available to them, intermediaries don't have enough information to know
whether they can cache responses, or transcode, or whatever their task
might be.

I think that WSD issue #64[1] covers your concern.  If it were resolved
such that HTTP methods, including GET, were given their rightful status
as WSDL operations, then that's all a developer has to know, and they
can write software that uses GET as it's defined in RFC 2616; any "safe"
or "idempotent" flag would be superfluous.


 [1] http://dev.w3.org/cvsweb/~checkout~/2002/ws/desc/issues/wsd-issues.html#x64

Mark Baker.  Ottawa, Ontario, CANADA.   http://www.markbaker.ca

   Will distribute objects for food
Received on Tuesday, 26 November 2002 14:09:31 UTC

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