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RE: URIQA thwarted by WebDAV properties?

From: <Patrick.Stickler@nokia.com>
Date: Tue, 12 Oct 2004 15:21:56 +0300
Message-ID: <1E4A0AC134884349A21955574A90A7A50ADD31@trebe051.ntc.nokia.com>
To: <elh@cs.pdx.edu>
Cc: <www-rdf-interest@w3.org>



> -----Original Message-----
> From: ext Eric Hanson [mailto:elh@cs.pdx.edu]
> Sent: 12 October, 2004 14:43
> To: Stickler Patrick (Nokia-TP-MSW/Tampere)
> Cc: www-rdf-interest@w3.org
> Subject: URIQA thwarted by WebDAV properties?
> 
> 
> Patrick.Stickler@nokia.com (Patrick.Stickler@nokia.com) wrote:
> > > BTW2, apologies for the sensational subject. It made me 
> cringe when I
> > > read it back the next day.
> > 
> > Please don't apologise. These are very good questions and 
> it has been
> > very beneficial to be able to cover them. I wish I had time to write
> > more about URIQA, particularly about rational and experience putting
> > it to work. Challenging questions are a good impetus to address alot
> > of these key issues.
> > 
> > Bring it on!  ;-)
> 
> Oh oh, I have one! :-)

:-)


> Ok, for starters I am a big fan of URIQA and have been since the
> beginning.  I think it's an absolutely right-headed approach
> towards getting the SW baloon off the ground.
> 
> My problem with it is that of implementation, and can be summed
> up in three words:  Why not WebDAV?

When I was first looking at this problem, I did look at WebDAV,
but found an imperfect match of semantics and application scope.

Either the semantics of the WebDAV methods were not exactly
what was needed (albeit close) or included far more than I
wanted to impose on URIQA-like implementations.

There was also some ambiguity about whether what URIQA means
by 'resource' is what WebDAV means by 'resource' (all this 
predates AWWW by quite a few years).

I don't have my notes handy at the moment and don't want to go
into details based on a fuzzy memory. But in a nutshell, at the
time, it didn't fit what I was needing/trying to do.

> Consider the following almost one-to-one mapping from URIQA's
> adventurous forrays into HTTP extensions to WebDAV's.  All
> definitions straight from the specs:
> 
> URIQA MGET
>   Return a concise bounded description of the resource denoted by
>   the request URI...
> WebDAV PROPFIND
>   The PROPFIND method retrieves properties defined on the resource
>   identified by the Request-URI...
> 
> URIQA MPUT/MDELETE
>   Add the statements contained in a concise bounded description of
>   the resource, provided as input, to the (possibly empty) body of
>   knowledge maintained about the resource denoted by the request
>   URI.
>   Remove the statements contained in a concise bounded
>   description of the resource, provided as input, from the
>   existing knowledge maintained about the resource denoted by the
>   request URI.
> WebDAV PROPPATCH
>   The PROPPATCH method processes instructions specified in the
>   request body to set and/or remove properties defined on the
>   resource identified by the Request-URI.
> 
> URIQA handles a single kind of metadata, the CBD.  WebDAV can
> handle any metadata that can be represented as XML.  Seems like
> WebDAV addresses the bigger and more generally-applicable
> problem of metadata at large and URIQA's CBD could fit pretty
> nicely in here.
> 
> Not to mention all the extra stuff you get with WebDAV as well.
> When you move a resource, you can just use the MOVE operation to
> relocate the resource and its metadata seamlessly.
> 
> When you want to search the metadata, you can use the SEARCH
> operation.  It's extensible so you can use any search grammer
> you want to (think XQuery/RDQL/...)
> 
> And not to be outdone is the COPY operation.  It copies a
> resource and its metadata from one location to another in a
> single operation.  Even across hosts according to the spec,
> though nobody implements that.

The way you present it above does motivate me to have another
look at WebDAV, though I'm also beginning to get tinglings of
memories of how/why these didn't quite fit the URIQA model.

> Being somewhat new to the list I hope this doesn't get me drawn
> and quartered 

Hey, there's never any risk of that on *this* list...   ;-)

> but I think WebDAV is actually a much nicer
> approach to implementing the vision of the Semantic Web.  The
> web was designed for documents, but metadata is data and should
> be handled with a protocol designed for working with data.
> URIQA gets this right, but I think WebDAV gets it righter. :-)

If/as I get some time in the next week or so, I'll try to
revisit this and offer some comments. It's probably fair to
add a section about WebDAV into the FAQ section of URIQA
anyway...

Cheers,

Patrick


> Regards,
> Eric Hanson
> --
> http://www.aquameta.com/~eric/
> http://typekit.org/
> 
Received on Tuesday, 12 October 2004 12:24:12 GMT

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