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

From: Paul Downey <paul.downey@whatfettle.com>
Date: Wed, 6 Sep 2006 08:44:28 +0100
Message-Id: <85354110-86B0-4E08-BFD6-B4A207452BF2@whatfettle.com>
Cc: public-web-http-desc@w3.org
To: Mark Baker <distobj@acm.org>


On 5 Sep 2006, at 20:35, Mark Baker wrote:

>
> +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.

In many ways both WADL and 'Forms' are the same - they're just
Web pages at the end of a URI describing what you might like
to send to another URI. Actually WADL is better than many HTML
forms in that there likely to be some Javascript magic to subvert the
results - it's all declarative.

I think it's the temporal nature which is the issue here - how long
can you leave between grabbing a WADL (or a HTML form) and then
making GET/POST requests based upon that information?

> 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...

In many ways the 'authoritative' nature of metadata is an orthogonal  
issue
given there are similar issues for all metadata, including Content-type.
It's tempting to specify a policy for a WADL or a form 'yes, we're  
committed
to supporting this' but then that's just more metadata about, um,  
metadata.

> 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).

Sounds interesting, but I'm having a strong sense of F&P deja-vu!

> 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
> WSDL).

Yeah, XML Schema isn't great for *describing* messages. A bag of a
profile of XPath would be my starting point for a message contents
description language.

> 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.

A WADL microformat, even?

--
http://blog.whatfettle.com
Received on Wednesday, 6 September 2006 07:44:52 UTC

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