def handle(self, url, method):
        """ Execute the handler bound to the specified url and method and return
        its output. If catchall is true, exceptions are catched and returned as
        HTTPError(500) objects. """
        if not self.serve:
            return HTTPError(503, "Server stopped")

        handler, args = self.match_url(url, method)
        if not handler:
            return HTTPError(404, "Not found:" + url)

        try:
            return handler(**args)
        except HTTPResponse, e:
            return e
        except Exception, e:
            if isinstance(e, (KeyboardInterrupt, SystemExit, MemoryError))\
            or not self.catchall:
                raise
            return HTTPError(500, 'Unhandled exception', e, format_exc(10))