[Zope] help! url <-> object mapping?

[Mark Anquoe]

I am relatively new to zope. Thank you in advance for any help.
here is my situation:

user enters url
zope maps url to object
zope stitches together a frames html page according to my structure of 
inherited attributes.
one of the html pages in the returned frameset needs to change itself 
depending on what type of object was asked for by the initial url request.

I know I can get the initial requested url through the request object

request = container.REQUEST

and I know that all these objects have meta_type attributes.
But how do I find a reference to the object to which zope has mapped the 
requested url that I can then test for its meta_type?
I keep coming back to this bit of code in the page:

fullpath = request.get('full')
if not fullpath:
  fullpath = '0:%s' % url_quote(request.URL1)

bookmarkid = context.db.get_link_id(fullpath)

something related to the unique ID looks promising, but I have found no 
api that details the various methods available to call on the context or 
db objects.

any help is appreciated.

thank you.