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Re: Is it a good idea to make your WADL available?

From: Mark Baker <distobj@acm.org>
Date: Tue, 5 Sep 2006 15:35:50 -0400
Message-ID: <c70bc85d0609051235r3e4bd8f0p44f9b1dd5925ffc3@mail.gmail.com>
To: public-web-http-desc@w3.org

+1, on all counts.

The frustrating thing here from my POV, is that WADL is very nearly a
forms language; consumable at runtime in order to direct a hypermedia
application.  It just needs a few tweaks, as well as to make clear
what's authoritative and what isn't.

Consider the news search example from the spec ...

The "request" stanza is an authoritative description of the parameters
needed to search news, so that's good... though I think it would help
to ground the parameters in URI space to provide a hook for automata
to infer parameters types (as I did with RDF Forms) - as is, it's only
good for human consumption (right back at ya, Sanjiva 8-), unless a
registry of parameter names and associated meanings is presumed (I
assume not).

The "response" stanza is non-authoritative though, because the
response message itself is authoritative.  As Noah discussed, there's
sometimes value in providing this information, but the costs of
counting on it need to be understood.  And as Mark seemed to imply
(and I agree), sometimes it's possible for those costs to exceed the
benefits.  For one, I'd definitely recommend removing schema from
there, as they're notoriously brittle since authors don't typically
account for extensibility  (another major complaint of mine against

The only other thing that WADL would require would be an integration
story; how to embed a WADL document inside documents containing other
languages.  It would imagine it could look something like XForms' - in
fact WADL would be competitive with XForms.


On 9/5/06, Mark Nottingham <mnot@mnot.net> wrote:
> On 2006/09/05, at 5:57 AM, Marc Hadley wrote:
> > Personally, even if the above turns out to be the dominant
> > paradigm, I still think there's utility in setting out a map of the
> > available resources and their supported methods and representations
> > and with APP and OpenSearch we already have existence proof that
> > such descriptions are useful. I just hope we can avoid a plethora
> > of such description languages.
> Well, *this* Mark agrees. However, as I tried to explain in my
> previous message WRT maps, it's the way that it's used -- on the
> server side as well as client side -- that's important.
> This reminds me too much of WS-* land to be a coincidence. A bunch of
> vendors threw a slew of tools over the wall, wrote a few papers about
> how things *should* be done, but the tools didn't really support
> those lofty thoughts too well. End users got confused and often ended
> up going with what was most familiar (RPC, etc.).
> Don't get me wrong -- I think WADL is the bee's knees, and very much
> want to see it succeed. However, looking at the landscape of possible
> ways it could help, and possible ways it could hurt, I'm inclined to
> be conservative -- possibly because I'm very directly accountable for
> the recommendations I make :)
> That's why I primarily see it as a modelling tool / convenience for
> design time, rather than something to give to clients. Not because
> those clients will misuse it -- as Marc pointed out earlier, they'll
> always find some way to misuse it -- but because it will lead people
> on the server side into the temptation of relying on it.
> Of course, the availability of compelling client-side tools that
> encourage good practice might help convince me otherwise.
> Cheers,
> --
> Mark Nottingham     http://www.mnot.net/
Received on Tuesday, 5 September 2006 19:36:04 UTC

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