树莓派如何实现mqtt通信

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1、sudo pip install paho-mqtt

2、python代码

# -*- coding: utf-8 -*-
import paho.mqtt.client as mqtt
# import RPi.GPIO as GPIO
import json,sys

# if sys.version_info < (3, 0):
# reload(sys)
# sys.setdefaultencoding('utf8')
# else:
# raw_input = input
username='public'
password='123456'
hostname='xxx.xxx.xxx.xxx'

# BCM GPIO编号
pins = [17,18,27,22,23,24,25,4]
def gpio_setup():
# 采用BCM编号
GPIO.setmode(GPIO.BCM)
# 设置所有GPIO为输出状态，且输出低电平
for pin in pins:
GPIO.setup(pin, GPIO.OUT)
GPIO.output(pin, GPIO.LOW)

def gpio_destroy():
for pin in pins:
GPIO.output(pin, GPIO.LOW)
GPIO.setup(pin, GPIO.IN)

# 连接成功回调函数
def on_connect(client, userdata, flags, rc):
print("Connected with result code " + str(rc))
# 连接完成之后订阅gpio主题
client.subscribe("gpio")

# 消息推送回调函数 .decode("utf-8")
def on_message(client, userdata, msg):

print(msg.topic+""+str(msg.payload))
#获得负载中的pin 和 value
# gpio = json.loads(str(msg.payload))

# if gpio['pin'] in pins:
# if gpio['value'] == 0:
# GPIO.output(gpio['pin'], GPIO.LOW)
# else:
# GPIO.output(gpio['pin'], GPIO.HIGH)

if __name__ == '__main__':
client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message
# gpio_setup()

try:
# 请根据实际情况改变MQTT代理服务器的IP地址及账户密码认证
#client.username_pw_set(username,password)
client.connect("xxx.xxx.xxx.xxx", 1883, 60)
client.loop_forever()
except KeyboardInterrupt:
client.disconnect()
gpio_destroy()

发送数据为{"pin":12,"value":1}

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