Rails - Apr 2006 - rails url to object reference

Hi all

Is there a quick utility to go from a url to an object reference, e.g.
http://rails/users/show/1 --> @user, but not through a browser ...?

I don''t want to access the object to look at it - I want the url string
itself to be interpreted - like for a wiki name in a wiki page

What would be best would be a function like:

return_object_ref(urlstring)

where urlstring = ''http://rails/users/show/4'' or whatever.

Anyone know if such a thing exists?

Many thanks in advance

CHEERS> SAM