def new_notebook_id(self, name):
        """Generate a new notebook_id for a name and store its mappings."""
        # TODO: the following will give stable urls for notebooks, but unless
        # the notebooks are immediately redirected to their new urls when their
        # filemname changes, nasty inconsistencies result.  So for now it's
        # disabled and instead we use a random uuid4() call.  But we leave the
        # logic here so that we can later reactivate it, whhen the necessary
        # url redirection code is written.
        #notebook_id = unicode(uuid.uuid5(uuid.NAMESPACE_URL,
        #                 'file://'+self.get_path_by_name(name).encode('utf-8')))
        
        notebook_id = unicode(uuid.uuid4())
        
        self.mapping[notebook_id] = name
        self.rev_mapping[name] = notebook_id
        return notebook_id
Generate a new notebook_id for a name and store its mappings.