Called when a client has opened a websocket connection

def onOpen(self):
        """
        Called when a client has opened a websocket connection
        """
        self.factory.add_client(self)

        # Publish ON_OPEN message
        self.factory.mease.publisher.publish(
            message_type=ON_OPEN, client_id=self._client_id, client_storage=self.storage)