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RE: What is DASL for?

From: Julian Reschke <julian.reschke@gmx.de>
Date: Sun, 9 Jun 2002 16:42:32 +0200
To: "Alan Kent" <ajk@mds.rmit.edu.au>, "WebDAV" <w3c-dist-auth@w3.org>
Message-ID: <JIEGINCHMLABHJBIGKBCMEKPELAA.julian.reschke@gmx.de>

> From: w3c-dist-auth-request@w3.org
> [mailto:w3c-dist-auth-request@w3.org]On Behalf Of Alan Kent
> Sent: Thursday, May 30, 2002 12:59 AM
> To: WebDAV
> Subject: What is DASL for?
> This might sound like a very naive question, but I am trying to understand
> the use cases for DASL. That is, what sorts of problems are people trying
> to solve? Being an open framework to drop any sort of query you like into
> it to me does not improve interoperability in the long term.
> ...
> Hence my question of what is the goal:
> * To enable searching of content? (Similar goals to say google)

It's important to understand that DASL consists of

a) a framework for the HTTP SEARCH method, enabling different kinds of query
grammars, and

b) one specific (and mandatory) query grammar, specialized in searching on
WebDAV properties (it has a single function for content matching, but this
is optional).

> * To enable searching through a file system to find files that match
>   certain properties (more like "Find Files" under windows") in a
>   way that is faster than the client doing PROPFIND etc on each
>   individual file.


> If the latter, I would implement the query engine without using indexes,
> and just do the file system walk at the server end and check the various
> conditions to find matching resources.

Well, that's up to you. Even if a DAV:basicsearch query affects both dead
(stored) and live (computed) properties, it may be able to come up with a
better query strategy that does not require a tree walk. See for instance
Elias' paper at [1].

[1] <http://dav.cse.ucsc.edu/dasl/mod_dav_dasl.pdf>
Received on Sunday, 9 June 2002 10:43:01 UTC

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