I've heard from OCLC staff that this is something they'd _like_ to do, 
but I don't believe they have it yet.

The trick here is that traditional library metadata practices make it 
_very hard_ to tell if a _specific volume/issue_ is held by a given 
library.  And those are the most common use cases for OpenURL.

If you just want to get to the title level (for a journal or a book), 
you can easily write your own thing that takes an OpenURL, and either 
just redirects straight to worldcat.org on isbn/lccn/oclcnum, or 
actually does a WorldCat API lookup to ensure the record exists first 
and/or looks up on author/title/etc too. 

Umlaut already includes the 'naive' "just link to worldcat.org based on 
isbn, oclcnum, or lccn" approach, functionality that was written before 
the worldcat api exists. That is, Umlaut takes an incoming OpenURL, and 
provides the user with a link to a worldcat record based on isbn, 
oclcnum, or lccn.

Jonathan

Tom Keays wrote:
> I know it is possible to sent OpenURL requests to the WorldCat Registry
> service and have it chose a local OpenURL resolver based on what IP address
> you are coming from.
>
> WorldCat OpenURL endpoint: http://worldcat.org/registry/gateway
>
> What I don't know is if WorldCat has an OpenURL resolver or can itself act
> as an endpoint for an OpenURL? I realize this is not the usual use case;
> normally an OpenURL would be searching against a knowledgebase of the
> holdings of a specific institution. With WorldCat, the OpenURL would have
> the holdings of all the constituent member libraries as its "knowledgebase".
> So, the purpose of this would be to discover where a given item represented
> by the OpenURL was held. A secondary purpose would be as a source of
> bibliographic citation information This could be quite useful discovery
> tool, especially for materials that are not widely held.
>
> Ditto the same question for OpenLibrary.
>
> Tom
>