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Call for volunteers: DAV Searching and Locating

From: Jim Whitehead <ejw@ics.uci.edu>
Date: Mon, 17 Apr 2000 13:10:12 -0400
To: WebDAV WG <w3c-dist-auth@w3.org>
Given the number of people on this mailing list, there are undoubtedly some
that haven't heard about the DAV Searching and Locating (DASL) group. I'm
writing to let you know a little bit about the group, and to encourage you
to sign up for the mailing list, and to participate in the development of
the DASL protocol.

The goal of DASL is to develop a protocol for remotely searching WebDAV
repositories. The DASL protocol will provide a new navigation mechanism,
adding to the existing hypertext point-and-click navigation, and
hierarchical collection navigation (introduced by WebDAV), for getting to
the resources you want to remotely author.  It differs from search engines
in that a search against an Internet search engine typically searches a
cached, and often stale view of the Internet, while DASL searches a single
repository (or group of cooperating repositories) using the exact contents
as of the moment of the search, providing a very fresh search result.

DASL becomes increasingly important as DAV repositories start to hold large
numbers of documents (tens, hundreds, and millions of documents), where
hypertext and hierarchical navigation do not work as effectively.  Thus,
DASL is a critical piece of technology as WebDAV matures, and more documents
are available via WebDAV.

Furthermore, DASL enables new kinds of applications to be created using
WebDAV.  Consider the Napster program. Napster, using a proprietary,
non-open network protocol, provides a centralized metadata database, which
remote clients search to find the location of a MP3 (or other) file. Once
the file is found, the Napster client downloads the file from the same
machine running the client, using the Napster protocol. Using DASL, it would
be possible to construct a Napster clone using off-the-shelf DAV
technology -- we could call it "DAVster".  A DAVster client would register
the resources (MP3 songs) it wanted to share with a remote DAV server,
storing only metadata on the remote server -- the shared resource (song)
itself would be located on an HTTP server someplace on the net, either on
the user's local machine, or, better yet, on a remote Web server.  When it
wanted to see what else was available, the DAVster client would perform a
DASL search against the metadata server.  The search response would give the
locations, as URLs, of the resources (songs) matching the query.  The
DAVster client would then do an HTTP GET against the returned URL(s) to
retrieve the desired resource (MP3 song).  Since HTTP is being used, it is
possible to take advantage of HTTP caching as well, reducing bandwidth
consumption, a current problem with Napster.

For more information on DASL, you can consult the DASL home page:

The DASL mailing list is: www-webdav-dasl@w3.org   To join the mailing list,
send a message to www-webdav-dasl-request@w3.org (that is, the name of the
list address, with "-request" added), with a message subject of "subscribe"
(that is, the subject line in your mail software should say "subscribe").

Much work has already taken place on DASL, but recently this work has slowed
down.  We need just a few more volunteers to help resolve a relatively small
set of open issues, and to review the protocol specification.  I think it's
pretty close to completion, and the work will go much faster once you add
your efforts to this cause.  So, if you have a few spare cycles, please
consider joining the DASL working group, and helping this protocol to

- Jim
Received on Monday, 17 April 2000 13:10:53 UTC

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