Python MQTT introduce essay

灰太狼 2023-06-07 12:24 91阅读 0赞

2019-10-15

MQTT in Python

  • MQTT(Message Queuing Telemetry Transport)
  • IoT(Internet of Things) protocol，
  • supports Python 2.7.9+ or 3.4+
  • include server,client(pub and sub)

  • message include

    • topic——message type,after subscriber subscribe the topic,it will receive the message content of the topic(payload)
    • payload——message content
  • Architecture diagram
    007X8olVly1g7yp2t4rulj30ua08z74c.jpg

  • install

    pip install paho-mqtt

 or with virtualenv

  1. virtualenv paho-mqtt
  2. source paho-mqtt/bin/activate
  3. pip install paho-mqtt

 full code

  1. git clone git://git.eclipse.org/gitroot/paho/org.eclipse.paho.mqtt.python.git

  • import

    import paho.mqtt.client as mqtt

  • example
    pub.py

    -- coding: utf-8 --

    import paho.mqtt.client as mqtt

    MQTTHOST = “127.0.0.1”
    MQTTPORT = 1883
    client = mqtt.Client()

  1. def connnect():
  2.     client.connect(MQTTHOST,MQTTPORT,60)
  4. def pub(topic,message,qos):
  5.     client.publish(topic,message,qos)
  6.     print('pub success!')
  8. def main():
  9.     connnect()
  10.     text=input('please input text:')
  11.     while text:
  12.         #send a message which topic is 'test' 
  13.         pub("test",text,2)
  14.         client.loop_start()
  15.         text=input('please input text:')
  18. if __name__=="__main__":
  19.     main()

  sub.py

  1. # -*- coding: utf-8 -*-
  2. import paho.mqtt.client as mqtt
  4. MQTTHOST = "127.0.0.1"
  5. MQTTPORT = 1883
  6. client = mqtt.Client()
  9. def connnect():
  10.     client.connect(MQTTHOST,MQTTPORT,60)
  11.     client.loop_start()
  13. def on_message(client,user,msg):
  14.     # msg.payload's type is bytes,so we must decode it
  15.     print("get message:topic=%s content=%s"%(msg.topic,msg.payload.decode()))
  17. def sub():
  18.     client.subscribe('test',2)
  19.     client.on_message=on_message #function to receive messages
  21. def main():
  22.     connnect()
  23.     sub()
  24.     while True:
  25.         pass
  26.     # client.loop_forever()
  28. if __name__=="__main__":
  29.     main()

  • runserver–mosquitto
    install
    https://mosquitto.org/download/

    notice:article’s example is for windows.

    run demo

    • terminal 1 for server

      mosquitto -d -v

    • terminal 2 for sub

      mosquitto_sub -t test

    • terminal 3 for pub

      mosquitto_pub -t test -m “haloha”

    while you excute the terminal 3’s command,the terminal 2 will display the message ‘haloha’.

  • run Python demo
    start mosquitto server

    1. mosquitto -d -v

    then run sub.py to to subscribe topic and run pub.py to send message.

  run sub.py

  result

  1. D:\PythonProject>python .\sub.py
  2. get message:topic=test content=hello
  3. get message:topic=test content=how are you

  run pub.py

  result

  1. D:\PythonProject> python  .\pub.py
  2. please input text:hello
  3. pub success!
  4. please input text:how are you
  5. pub success!

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