Subject: Namespace consistency

From: Jim Whitehead <[email-masked]>
Date: Thu, 10 Sep 1998 11:32:02 -0700

Larry Masinter writes:
># DAV compliant
>#   resources MUST maintain the consistency of the HTTP URL namespace.
>
>Is there a definition of what 'the consistency of the HTP URL namespace'
>means? It's not defined anywhere, and this sentence only gives an example.

This does appear to be an omission in the specification.

By consistency, we meant:

No gaps: Given HTTP URL U, for all unique HTTP URL Ux, where Ux is
constructed from U by removing all characters to the right of a "/", Ux MUST
be the HTTP URL of a WebDAV collection.

So, if there is an HTTP URL:

http://www.foo.bar.org/a/b/c

Then

http://www.foo.bar.org/a/b/
http://www.foo.bar.org/a/

MUST be HTTP URLs of WebDAV collection resources.

There are two ways to maintain this consistency when a new resource is
created:

a) create intermediate collections automatically
b) refuse to create a resource if intermediate collections do not yet exist.

The example in Section 4.3 implies we were recommending option b).

Also, consistency implies:

100% containment: Given HTTP URL U, U MUST be a member URL of the collection
whose URL, Uc, is contructed by removing the trailing path segment of U.
Exception: when U is the top-level resource, "/", of a namespace (i.e., the
first slash after the domain name in an HTTP URL), it belongs to no
collection, since it is the URI of the root collection.

- Jim

---

From: Fisher Mark <[email-masked]>
Date: Mon, 14 Sep 1998 12:32:16 -0500

>I have been meaning to complain about this for a while but didn't because
>it seems to be trivial.  I was having a hard time imagining anyone being so
>picky as to insist on this point (and, perhaps, denying me the covetted
>"100 % Pure DAV" sticker for my server?) but perhaps it's better to face it
>now.  In fact, this very issue has been raised in some discussions internal
>to Xerox.  People have said to me "We would like to support DAV methods in
>this subtree but we don't want to support them on the root but the protocol
>says we MUST do it, so can we still use DAV?".  So Howie isn't the only one
>worrying about it.
>
>I say, strike the restriction.

Based on my experiences as a webmaster, I'd agree.  I really don't see any
prospect of webmasters wanting to have only root-based subtrees (like
<URL:http://www.foo.com/bar/>) be DAV-compliant.  DAV will work and play
better with others if it can be restricted to non-root-based subtrees.  Not
that some servers won't want to be set up using DAV for all document
management -- just that some (probably the majority) will not use DAV for
all document management, for various political/social/technical reasons.
> ==========================================================
> Mark Leighton Fisher          Thomson Consumer Electronics
> [email-masked]          Indianapolis, IN
> "Browser Torture Specialist, First Class"
>

---

From: Yaron Goland <[email-masked]>
Date: Tue, 15 Sep 1998 00:01:45 -0700

My reading of the DAV spec is that both Jim's statement (the parents of a
DAV resource do not have to be a DAV resource) and Larry's language (the
child of a DAV resource doesn't have to be a DAV resource) are BOTH correct
and BOTH supported by the spec. The language in the spec is phrased as "If a
resource is DAV compliant THEN ....."

In the particular case Larry lists my understanding of the spec is that if
http://a/b/c IS DAV compliant then http://a/b/c/d.cgi WOULD be listed as a
member of http://a/b/c EVEN THOUGH it isn't itself DAV compliant. The
requirement for listing is only on http://a/b/c because it is DAV compliant
but this puts no onus on http://a/b/c/d.cgi to be DAV compliant.

				Yaron

> -----Original Message-----
> From: Larry Masinter [mailto:[email-masked]]
> Sent: Monday, September 14, 1998 8:44 PM
> To: Jim Davis; WebDAV WG
> Subject: RE: Namespace consistency
> 
> 
> 
> > > I think we should require all collections below a DAV-compliant
> > >resource to also be DAV-compliant.  So, while it's OK to not be
> > >DAV-compliant looking up a hierarchy tree, looking down 
> the tree from a
> > >DAV-compliant location should always be DAV-compliant. 
> > 
> > Strongly agree.
> 
> So a DAV-compliant resource can't be, say, a CGI script? Even in
> 'advanced DAV'?
> 
> If I have http://a/b/c/ and I want to add a CGI such that
>  http://a/b/c/d is indirectly http://a/b/c/d.cgi, where
> 'd.cgi' computes a query, you might have http://a/b/c/d?e .
> Now, is http://a/b/c/d.cgi a 'member' of http://a/b/c/ ?
> 
> Larry
> --
> http://www.parc.xerox.com/masinter
>  
> > 
> > 
>