Target-Selector

Tim Ellison OTT (Tim_Ellison@oti.com)
Wed, 22 Dec 1999 10:48:40 -0500


From: Tim_Ellison@oti.com (Tim Ellison OTT)
To: ietf-dav-versioning@w3.org ('Delta V')
Message-ID: <1999Dec22.104500.1250.1425599@otismtp.ott.oti.com>
Date: Wed, 22 Dec 1999 10:48:40 -0500
Subject: Target-Selector


I'd like to propose a change to the Target-Selector as described in the 
protocol spec.

Presently, the valid values are:
     workspace "<URI>"
     id "<revision id>"
     label "<label>"
     metadata

The change would accomodate the situation where the client wants to select 
collection revisions using a workspace, and the final resource using a label 
or id.  Without such a change the "id" target selector is of little/no use 
for selecting resources in collections (the collection will not have the 
same id as the "leaf" resource).

The change would also allow the client to select a revision based directly 
upon an activity and provides extensibility for other selection schemes.

target selector = Target-Selector ":" URI [ LWS "; finally" URI ]

The use of URIs gives us extensibility for defining new selection 
mechanisms, and the optional "finally" clause allows clients to specify a 
different selector for the leaf.  (I don't see any benefit for N selection 
methods.)

Example URIs would be id:some_id, label:some_label, metadata:, and 
http://machine/resource where 'resource' is a workspace or activity or 
something else (the server gets to figure out which by looking at the 
resource type).  Specifying a resource that cannot be used for selection 
results in a bad request.

Example target selectors would be:
  Target-Selector: http://foo.com/mywork
  Target-Selector: http://foo.com/mywork ; finally id:Rev12FP
  Target-Selector: label:bar ; finally http://foo.com/actif1

Comments?
Tim