In one of our sites, we are getting related content through an ajax call where the url is the sent to the file. I'm currently assuming that the url is the alias of the document, which obviously isn't always the case, and I need to resolve this by finding a way to match the URL provided to search for the proper document node/alias.

I've been trying to find something in the Developer's Guide that helps in this, but I have been unsuccessful thus far. Can someone help point me in the right direction?