RE: [xml-dev] best practice for providing newsfeeds ?

["Bullard, Claude L (Len)" <clbullar@ingr.com>]

And a similar approach is what X3D/VRML takes to 
the Universal Media library for handling library 
objects for web3D although the unique names are 
looser.  

http://www.web3d.org/WorkingGroups/media/course/index.htm

This has been successfully implemented 
for the new Vizx3D editor and Flux browsers.

http://www.vizx3d.com

For example:

"texture ImageTexture {
  url [
    "urn:web3d:media:textures/nature/grass_1.jpg",
    "http://www.web3d.org/WorkingGroups/media/textures/nature/grass_1.jpg";
  ]
}
All Universal Media URNs begin with "urn:web3d:media:", which is, in
essence, a variable that is dynamically mapped at runtime to the folder on
the user's hard drive that contains Universal Media textures, sounds, and 3D
objects. In other words, at runtime the VRML browser converts the name
"urn:web3d:media:" into an actual folder path where the media elements can
be found. This is necessary because Universal Media is a cross-platform
system, and so hard-coded references to media are not practical or even
possible: Every end user configuration offers a potentially unique path
leading to Universal Media, which the browser must resolve at runtime. URNs
solve this problem, as explained in the Universal Media Working Group's
"VRML, URNs, and Universal Media" Recommended Practice document."

len



From: jcowan@reutershealth.com [mailto:jcowan@reutershealth.com]

IMHO the urn:newsml: scheme is a huge win in this respect.  The details
are at http://www.ietf.org/rfc/rfc3085.txt , but the general scheme is
this:

	urn:newsml:example.com:20040203:SLUG:1

Of these six parts, "urn" and "newsml" are fixed.  The third part is a
domain
which the issuer of the item owns.  The fourth part gives an ISO 8601 date,
such that the issuer owned the domain during the whole of that date.  This
allows for the fact that more than one entity can control a domain name
at different times.

The fifth part is a string that taken jointly with the third and fourth
parts makes a string to the issuer.  The sixth part is a version
number, which must be positive (zero is forbidden) and which must increase
with every new version (it need not increase by 1), possibly followed by "A"
or
"U", which mean that this item is metadata-only or a diff respectively;
otherwise,
it is a replacement.

With this scheme, there is a globally unique URI for every version of every
item, but it is trivial to find the latest (or earliest, or whatever)
version
of a particular item identified by the first five parts.

Reuters Health URNs look like this:

	urn:newsml:reutershealth.com:20040203:elin001:1

The domain-valid date doubles as the date of first publication, and the
slug specifies the newswire and an arbitrary three-digit number within that
newswire: taken jointly with "reutershealth.com", this represents a unique
story.  This particular one is the first and only version.