mqtt_client_shell.py 文件源码

def publish(self, topic, payload, qos=0, retain=False):
        """Publish a message, with the given parameters.
        Substitute in the _msg_seq if the payload contains {seq}."""
        if not topic:
            print("Topic must be specified")
        else:
            if not payload: 
                print("Payload not specified, so a zero-length message will be published.")
                payload = None
            elif (not isinstance(payload, bytearray)) and ("{seq}" in payload):
                payload = payload.format(seq=self._msg_seq)

            (result, msg_id) = self._mqttclient.publish(topic=topic, payload=payload, qos=qos, retain=retain)
            print("...msg_id={!r}, result={} ({})".format(msg_id, result, mqtt.error_string(result)))
            if result == mqtt.MQTT_ERR_SUCCESS:
                self._msg_seq += 1