python简单应用mqtt

一.搭建mqtt服务器

1. 推荐使用EMQX
2. 下载地址(windows版本)：https://www.emqx.io/downloads/broker/v4.1-rc.2/emqx-windows-v4.1-rc.2.zip
3. 启动mqtt服务器 ：D:>\emqx\bin>emqx.cmd start
4. 关闭mqtt服务器 ：D:>\emqx\bin>emqx.cmd stop
5. 访问地址：http://127.0.0.1:18083
6. 用户名/密码：admin/public

二.编写代码

2.1 安装mqtt模块

pip install paho-mqtt

2.2 发布客户端

发布客户端：publish.py

import paho.mqtt.client as mqtt

def on_connect(client, userdata, flags, rc):
    print("Connected with result code: " + str(rc))

def on_message(client, userdata, msg):
    print(msg.topic + " " + str(msg.payload))

client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message
client.connect('127.0.0.1', 1883, 600) # 600为keepalive的时间间隔
client.publish('测试', payload='测试通过啦', qos=0)

2.3 接收客户端

接收客户端：subscribe.py

import paho.mqtt.client as mqtt

def on_connect(client, userdata, flags, rc):
    print("Connected with result code: " + str(rc))

def on_message(client, userdata, msg):
    print(msg.topic + " " + str(msg.payload))

client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message
client.on_disconnect = on_disconnect
client.connect('127.0.0.1', 1883, 600) # 600为keepalive的时间间隔
client.subscribe('测试', qos=0)
client.loop_forever() # 保持连接