目前,我正在尝试使用MQTT,Python和OpenHab来制作一个简单的应用程序。所以,我只想连接到MQTT服务器,订阅主题并阅读放置在那里的数据/消息。 Everthing工作正常,但有“限制”。 Python客户端能够连接到MQTT,订阅和... BOOM!没有!我能够从订阅的主题中读取消息,但是我需要在客户端连接后更新主题。客户端连接后,如果没有重新更新主题数据,即使存在真实数据,我也无法看到任何内容。 因此,在短暂的阅读关于订阅的MQTT主题
- Python客户端(PAHO MQTT 1.3V)连接到MQTT(mosquitto)服务器
- 订阅了指定的主题(想在这里看到当前主题数据)
- 没有任何反应,直到有人会重新更新主题。
如何在不重新更新该主题的情况下阅读主题数据?
这里是我的代码 类MQTTBroker(对象):
def __init__(self, Trigger, ipAddress, userName, password, fileNameTopic, volumeTopic, enabledTopic):
self.ipaddress = ipAddress
self.username = userName
self.password = password
self.topic = topic
self.fileNameTopic = fileNameTopic
self.volumeTopic = volumeTopic
self.enabledTopic = enabledTopic
self.state = 0
self.client = mqtt.Client()
self.client.on_connect = self.on_connect
self.client.on_message = self.on_message
self.logger = logging.getLogger(__name__)
self.client.enable_logger(logger)
self.client.connect(self.ipaddress, 1883, 60)
self.client.loop_start()
def __exit__(self, exc_type, exc_val, exc_tb):
self.client.loop_stop()
# The callback for when the client receives a CONNACK response from the server.
def on_connect(self, client, userdata, flags, rc):
print("Connected with result code " + str(rc))
# Subscribing in on_connect() means that if we lose the connection and
# reconnect then subscriptions will be renewed.
self.client.subscribe(self.fileNameTopic, 0)
self.client.subscribe(self.volumeTopic, 0)
self.client.subscribe(self.enabledTopic, 0)
# The callback for when a PUBLISH message is received from the server.
def on_message(self, client, userdata, msg):
self.state = msg.payload
if msg.topic == self.fileNameTopic:
Trigger.change_file_name(msg.payload)
elif msg.topic == self.volumeTopic:
Trigger.change_volume(msg.payload)
elif msg.topic == self.enabledTopic:
Trigger.change_state(msg.payload)