resolver.py 文件源码

def resolve_reference(cls, design_ref):
        """Resolve a reference to a design document.

        Locate a schema handler based on the URI scheme of the data reference
        and use that handler to get the data referenced.

        :param design_ref: A URI-formatted reference to a data entity
        """
        try:
            design_uri = urllib.parse.urlparse(design_ref)

            handler = cls.scheme_handlers.get(design_uri.scheme, None)

            if handler is None:
                raise errors.InvalidDesignReference(
                    "Invalid reference scheme %s: no handler." %
                    design_uri.scheme)
            else:
                # Have to do a little magic to call the classmethod as a pointer
                return handler.__get__(None, cls)(design_uri)
        except ValueError:
            raise errors.InvalidDesignReference(
                "Cannot resolve design reference %s: unable to parse as valid URI."
                % design_ref)