python3对emqtt的简单操作

需要先下载外部包

pip install paho-mqtt

发布者

import paho.mqtt.client as mqttHOST = "192.168.44.31"PORT = 1883def Publish_Message():    client = mqtt.Client()    client.username_pw_set(username='admin', password='public')  # 用于添加了插件认证方式后    client.connect(HOST, PORT, 60)    for x in range(10):        Message = "hello" + str(x)        client.publish("services", Message, 0)  # 发布一个主题为'services',内容为'hello x'的信息    # time.sleep(10)    client.loop_forever()  # 保持连接状态if __name__ == '__main__':    Publish_Message()

发布者，主要内容：publish("topic_name","utf8_message",Qos)

• Qos:0 --> 发送者只发送一次消息，不进行重试，Broker不会返回确认消息。Broker可能没有接收到消息。（默认）
• Qos:1 --> 发送者最少发送一次消息，确保消息达到Broker，Broker需要返回确认消息PUBACK。Broker可能接收到重复消息。
• Qos:2 --> 使用两阶段确认来保证消息的不丢失和不重复。Broker肯定会接收到消息，且只收到一次。

订阅者

import paho.mqtt.client as mqttdef on_connect(client, userdata, flags, rc):    print("Connected with result code "+str(rc))  # rc表示返回来的状态值    client.subscribe("services")def on_message(client, userdata, msg):    print(msg.topic+" " + ":" + str(msg.payload))if __name__ == "__main__":    client = mqtt.Client()    client.on_connect = on_connect    client.on_message = on_message    client.username_pw_set(username='admin', password='public')  # 用于添加了插件认证方式后    client.connect("192.168.44.31", 1883, 60)    client.loop_forever()

订阅者，信息的产出在msg.payload

rc值代表的含义：
0: Connection successful
1: Connection refused - incorrect protocol version
2: Connection refused - invalid client identifier
3: Connection refused - server unavailable
4: Connection refused - bad username or password
5: Connection refused - not authorised
6-255: Currently unused.