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RE: SEARCH for displayname

From: Julian Reschke <julian.reschke@gmx.de>
Date: Tue, 9 Sep 2003 15:24:59 +0200
To: "Wallmer, Martin" <Martin.Wallmer@softwareag.com>, "'Julian Reschke'" <julian.reschke@gmx.de>, <www-webdav-dasl@w3.org>
Message-ID: <JIEGINCHMLABHJBIGKBCAEIGIGAA.julian.reschke@gmx.de>
RE: SEARCH for displaynameHm.

It doesn't necessarily need to compute the scope *before* doing the query,
right?

Julian
--
<green/>bytes GmbH -- http://www.greenbytes.de -- tel:+492512807760

  -----Original Message-----
  From: Wallmer, Martin [mailto:Martin.Wallmer@softwareag.com]
  Sent: Tuesday, September 09, 2003 3:22 PM
  To: 'Julian Reschke'; Wallmer, Martin; www-webdav-dasl@w3.org
  Subject: RE: SEARCH for displayname


  Somehow the server must calculate the scope, before the internal query
takes place. Couldn't that be a place for the <include> <exclude> filtering?

  Martin
    -----Original Message-----
    From: Julian Reschke [mailto:julian.reschke@gmx.de]
    Sent: Dienstag, 9. September 2003 13:47
    To: Wallmer, Martin; www-webdav-dasl@w3.org
    Subject: RE: SEARCH for displayname


    Here are some concerns making it an extension to the scope:

    Many servers will actually store resources and their bindings
separately. DAV:basicsearch is a search on properties (and content), thus
internally the server may query for the resources, and only will manufacture
URIs for the resource objects as a final step before reporting the result.
If filtering by names happens *after* internal execution of the query, the
maxresults element cannot be passed to the query.

    So we really should also consider moving the feature into the query,
defining a new specific operator for it.

    Julian
    --
    <green/>bytes GmbH -- http://www.greenbytes.de -- tel:+492512807760

      -----Original Message-----
      From: Julian Reschke [mailto:julian.reschke@gmx.de]
      Sent: Monday, September 08, 2003 3:49 PM
      To: Wallmer, Martin; 'Julian Reschke'; www-webdav-dasl@w3.org
      Cc: Pill, Juergen; Nevermann, Dr., Peter; Hartmeier, Michael
      Subject: RE: SEARCH for displayname


      I'm adding it to the issues list for now. Maybe you want to experiment
with a scope element extension and report back to the list if this turns out
to work for you.


      Julian
      --
      <green/>bytes GmbH -- http://www.greenbytes.de -- tel:+492512807760

        -----Original Message-----
        From: Wallmer, Martin [mailto:Martin.Wallmer@softwareag.com]
        Sent: Monday, September 08, 2003 3:46 PM
        To: 'Julian Reschke'; Wallmer, Martin; www-webdav-dasl@w3.org
        Cc: Pill, Juergen; Nevermann, Dr., Peter; Hartmeier, Michael
        Subject: RE: SEARCH for displayname


        Hi,

        thats correct, however how is the state of that discussion?

        To summarize this issue:

        Using <href> in the where clause is not possible
        Using <displayname> is not sufficient, as it is no "MUST" property
        making 1:1 mapping between <displayname> and <href> is not possible

        Did I miss something?
        I'd like to go into discussion again with this issue.

        Best regards,
        Martin




        -----Original Message-----
        From: Julian Reschke [mailto:julian.reschke@gmx.de]
        Sent: Montag, 8. September 2003 15:15
        To: Wallmer, Martin; www-webdav-dasl@w3.org
        Cc: Pill, Juergen; Nevermann, Dr., Peter; Hartmeier, Michael
        Subject: RE: SEARCH for displayname



        > From: www-webdav-dasl-request@w3.org
        > [mailto:www-webdav-dasl-request@w3.org]On Behalf Of Wallmer,
Martin
        > Sent: Monday, September 08, 2003 12:53 PM
        > To: 'www-webdav-dasl@w3.org'
        > Cc: Pill, Juergen; Nevermann, Dr., Peter; Hartmeier, Michael
        > Subject: SEARCH for displayname
        >
        >
        > Hello,
        > A common usecase for DASL is to search documents with specific
names, for
        > example all documents with the ending "doc", or following a
certain naming
        > pattern (for example chapter*.pdf).

        Known issue, see

<http://lists.w3.org/Archives/Public/www-webdav-dasl/2002JanMar/0108.html>.

        > Thinking straightforward you would say something like:
        > ...
        > <where>
        >   <like>
        >     <prop>
        >       <displayname/>
        >     </prop>
        >     <literal>
        >       chapter%.pdf
        >     </literal>
        >   </like>
        > </where>
        > ...
        >
        > However, the WebDAV spec says for property "displayname":
        > -------------------
        > Purpose:
        > Provides a name for the resource that is suitable for presentation
to a
        > user.
        > Description:
        > The displayname property SHOULD be defined on all DAV compliant
resources.
        > If present, the property contains a description of the resource
that is
        > suitable for presentation to a user.
        > -------------------

        In general, this means that

        a) you can't rely on DAV:displayname being present (for instance, it
won't
        be on our server or on Apache/moddav unless you previously set it)
and

        b) you can't assume that there's any relationship between
DAV:displayname
        and the "resource name".

        > Regarding BIND, the server has no chance to maintain a useful
        <displayname>
        > information, as several paths may point to the same resource, for
example
        > /myplayground/test.pdf and /handbook/chapter1.pdf could both point
to the

        Wrong. If a server uses DAV:displayname to store "a description of
the
        resource that is
        suitable for presentation to a user" it's perfectly ok if it doesn't
vary on
        the request URL. After all, it's a description of the resource, not
of the
        URL.

        > same resource. Regarding our usecase, the URL
        > /handbook/chapter1.pdf should
        > be returned, or to speak more abstract, return the URL, where the
        > last path
        > segment matches the searchpattern.
        > Currently it is not possible to pose this kind of query with DASL.
I see 3
        > options to express this:
        > 1. a new language element in <where>
        > <where>
        >   <lastpathsegment>
        >     <literal>
        >       chapter%.pdf
        >     </literal>
        >   </lastpathsegment>
        > </where>
        >
        >
        > 2. a new live property, for example
        > <where>
        >   <like>
        >     <prop>
        >       <lastpathsegment/>
        >     </prop>
        >     <literal>
        >       chapter%.pdf
        >     </literal>
        >   </like>
        > </where>
        > 3. introduce a new element in <scope>
        >     <d:from xmlns:d="DAV:">
        >       <d:scope>
        >         <d:href>/handbook/</d:href>
        >         <d:depth>infinity</d:depth>
        >         <d:include>chapter%.doc</d:include>
        >       </d:scope>
        >     </d:from>
        >
        >
        >
        > 1. would affect only DASL. Not clear, if it should match exactly
or match
        the pattern.

        Probably we would want "like" matching.

        > 2. would possibly affect the WebDAV spec as well, PROPFIND should
return
        this property as well.

        That would introduce a property that varies on the request URL,
something I
        really don't like.

        > 3. would affect only DASL. As the last path segment deals with the
URI,
        the scope is not a too bad place.

        Sounds reasonable.

        > Any other options?

        We could try to express it as a special operator that matches
specific
        values of DAV:parent-set (as defined in the binding spec). However
that's
        not really different from option 1).

        I think extending "scope" makes a lot of sense.

        Julian

        --
        <green/>bytes GmbH -- http://www.greenbytes.de -- tel:+492512807760
Received on Tuesday, 9 September 2003 09:25:56 GMT

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