Python MQTT introduce essay

灰太狼 2023-06-07 12:24 5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

virtualenv paho-mqtt
    source paho-mqtt/bin/activate
    pip install paho-mqtt

full code

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()
    
    
    def connnect():
        client.connect(MQTTHOST,MQTTPORT,60)
    
    def pub(topic,message,qos):
        client.publish(topic,message,qos)
        print('pub success!')
        
    def main():
        connnect()
        text=input('please input text:')
        while text:
            #send a message which topic is 'test' 
            pub("test",text,2)
            client.loop_start()
            text=input('please input text:')
    
    
    if __name__=="__main__":
        main()

**sub.py**

# -*- coding: utf-8 -*-
    import paho.mqtt.client as mqtt
     
    MQTTHOST = "127.0.0.1"
    MQTTPORT = 1883
    client = mqtt.Client()
    
    
    def connnect():
        client.connect(MQTTHOST,MQTTPORT,60)
        client.loop_start()
    
    def on_message(client,user,msg):
        # msg.payload's type is bytes,so we must decode it
        print("get message:topic=%s content=%s"%(msg.topic,msg.payload.decode()))
    
    def sub():
        client.subscribe('test',2)
        client.on_message=on_message #function to receive messages
        
    def main():
        connnect()
        sub()
        while True:
            pass
        # client.loop_forever()
    
    if __name__=="__main__":
        main()

*  runserver–mosquitto  
    **install**  
    [https://mosquitto.org/download/][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**
    
        mosquitto -d -v
    
    then run sub.py to to subscribe topic and run pub.py to send message.

**run sub.py**  
  
  result

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

**run pub.py**  
  
  result

D:\PythonProject> python  .\pub.py
    please input text:hello
    pub success!
    please input text:how are you
    pub success!

[007X8olVly1g7yp2t4rulj30ua08z74c.jpg]: /images/20230601/65cdb16dfded48f3b280f8a33f8d8906.png
[https_mosquitto.org_download]: https://mosquitto.org/download/