def get_canonical_path(resource_key, pk=None):
        """
        Return canonical resource path.

        Arguments:
            resource_key - Canonical resource key
                           i.e. Serializer.get_resource_key().
            pk - (Optional) Object's primary key for a single-resource URL.
        Returns: Absolute URL as string.
        """

        if resource_key not in resource_map:
            # Note: Maybe raise?
            return None

        base_path = get_script_prefix() + resource_map[resource_key]['path']
        if pk:
            return '%s/%s/' % (base_path, pk)
        else:
            return base_path