from twisted.internet import endpoints
from twisted.web import server, xmlrpc


class EchoHandler:
    def echo(self, x):
        """
        Return all passed args
        """
        return x


class AddHandler:
    def add(self, a, b):
        """
        Return sum of arguments.
        """
        return a + b


class Example(xmlrpc.XMLRPC):
    """
    An example of using you own policy to fetch the handler
    """

    def __init__(self):
        xmlrpc.XMLRPC.__init__(self)
        self._addHandler = AddHandler()
        self._echoHandler = EchoHandler()

        # We keep a dict of all relevant
        # procedure names and callable.
        self._procedureToCallable = {
            "add": self._addHandler.add,
            "echo": self._echoHandler.echo,
        }

    def lookupProcedure(self, procedurePath):
        try:
            return self._procedureToCallable[procedurePath]
        except KeyError as e:
            raise xmlrpc.NoSuchFunction(
                self.NOT_FOUND, "procedure %s not found" % procedurePath
            )

    def listProcedures(self):
        """
        Since we override lookupProcedure, its suggested to override
        listProcedures too.
        """
        return ["add", "echo"]


if __name__ == "__main__":
    from twisted.internet import reactor

    r = Example()
    endpoint = endpoints.TCP4ServerEndpoint(reactor, 7080)
    endpoint.listen(server.Site(r))
    reactor.run()