Web Services Description Requirements

The Web Services folks have published a last-call requirements document [1]
for Services Description

Some initial comments:

The spec is hard to read - with no scenarios explaining what requirements
mean in practice, and no explanation of the interaction of requirements, it
takes a fair bit of pondering the implications and guessing at what the group
is thinking a requirement really means.

There are a couple that seem important to us:

R110 The description language SHOULD allow indicating how long a Web Service
is going to take to process the request. This is just a hint to the Client,
and the Web Service would not be obligated to respect what it advertised.
(From WV. Special case of R117.)

(Apart from the fact that obligated should be replaced by obliged, this is
important for people who have trouble understanding what is going on, and
need to be told that they can expect to wait, or have their user agent do
something else to keep them busy...)

R026 The description language MUST provide human-readable comment
capabilities.  (From the Charter. Last discussed 28 Feb 2002.)

R123 The content model for human-readable comment capabilities MUST be open.
(From RD. Last discussed 11 June 2002.)

I think these two allow, for example, an XHTML description of what the
service does, plus an SVG diagram of how it works, or some MathML expressing
the way it processes some inputs, or whatever. I think that's important to

To help me think about this I used a few mental sketches of scenarios:

Screen scraping for information in RDF - trying to construct a calendar from
various kinds of input.

Asking a service to provide a view of a page that matched a particular users

Trying to put two or three services together in a chain - including finding
the right services that can be chained together. Again, the use case I was
thinking of is making a version of a page that meets a particular user's


[1] Requirements document http://www.w3.org/TR/ws-desc-reqs/



Charles McCathieNevile  http://www.w3.org/People/Charles  tel: +61 409 134 136
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Received on Thursday, 14 November 2002 10:21:49 UTC