- From: Yaron Goland <yarong@microsoft.com>
- Date: Tue, 18 Aug 1998 17:52:24 -0700
- To: "'Jim Davis'" <jdavis@parc.xerox.com>, WebDAV <w3c-dist-auth@w3.org>
- Cc: Larry Masinter <masinter@parc.xerox.com>
I thought the reason references don't solve the problem is that in the cases where all the security/scalability/consistency matters are resolved it still isn't possible for a resource to declare "I am contained in the following collections." Yaron > -----Original Message----- > From: Jim Davis [mailto:jdavis@parc.xerox.com] > Sent: Tuesday, August 18, 1998 5:08 PM > To: WebDAV > Cc: Larry Masinter > Subject: RE: Hierarchical URLs and Collections > > > At 01:01 PM 8/18/98 PDT, Larry Masinter wrote: > > [I suggest] that there > >be a DAV:parents property and that interoperable clients ... use > > PROPFIND of DAV:parents in order > >to walk up the hierarchy, rather than just trying to parse the URL > >tree. It's simple, backward compatible, doesn't cost much in terms of > >server implementation, and much more resiliant. > > This proposal resembles some proposals that were discussed in > the context > of so-called 'strong' references, and which were found > problematic then. > > 1) for the common case (internal membership) it adds no > value, because one > can find the parent container by mere syntax. > > 2) for the uncommon case (referential membership), it's > problematic, because: > 1. Security: When I create a referential resource whose > target is another > resource I may not have the access to the target resource to > set the back > pointer. > 2. Privacy: I may not want the target to know I am linking to it > 3. Scalability: If the target is very very popular it won't scale. > > Also, I don't see that it addresses the actual concerns > raised by the DMS > community, as opposed to those that came up as side issues in the long > discussion. In my opinion, referential resources suffice to > completely and > fully support such DMS systems. > > Furthermore, if it turns out that supporting such a property is a good > idea, then I suggest the right thing is for the DMS vendor to > implement it, > gain some experience, then propose it for a future version of > WebDAV. In > fact, we should look closely at the DMA API, which defines > two models of > containment, Direct and Referential. WebDAV has the former, and your > proposal is like the latter. To support Referential > containment requires > general graph manipulation (as Y. Goland pointed out) and/or > transactions > (which DMA has, sort-of). > > But anyway, unless someone can show why referential resources > do not solve > the DMS vendor's problems fully, we should close this issue. > > Jim > > > > > ------------------------------------ > http://www.parc.xerox.com/jdavis/ > 650-812-4301 >
Received on Tuesday, 18 August 1998 20:52:07 UTC