MQTT
MQTT 是一种基于发布/订阅(publish/subscribe)模式的“轻量级”通讯协议 。本章介绍如何在 RT-Thread MicroPython 上使用 MQTT 功能,使用到的模块为 umqtt.simple
模块。
获取并安装 umqtt.simple 模块
同样的可以使用包管理中的两种方式来获取,使用 upip 安装的方式可使用 upip.install("micropython-umqtt.simple")
如图:
umqtt.simple 模块的使用
MQTT 订阅功能
- 使用
iot.eclipse.org
作为测试服务器
import time
from umqtt.simple import MQTTClient
# Publish test messages e.g. with:
# mosquitto_pub -t foo_topic -m hello
# Received messages from subscriptions will be delivered to this callback
def sub_cb(topic, msg):
print((topic, msg))
def main(server="iot.eclipse.org"): # 测试 server 为 iot.eclipse.org
c = MQTTClient("RT-Thread", server)
c.set_callback(sub_cb)
c.connect()
c.subscribe(b"foo_topic") # 订阅 foo_topic 主题
while True:
if True:
# Blocking wait for message
c.wait_msg()
else:
# Non-blocking wait for message
c.check_msg()
# Then need to sleep to avoid 100% CPU usage (in a real
# app other useful actions would be performed instead)
time.sleep(1)
c.disconnect()
if __name__ == "__main__":
main()
- 使用 python 命令执行上述代码文件,就会连接上 MQTT 服务器,可收到我们从另一个客户端发布的以
foo_topic
为主题的内容
MQTT 发布功能
- 执行下面的代码后将向 MQTT 服务器发布以
foo_topic
为主题的信息
from umqtt.simple import MQTTClient
# Test reception e.g. with:
# mosquitto_sub -t foo_topic
def main(server="iot.eclipse.org"):
c = MQTTClient("SummerGift", server)
c.connect()
c.publish(b"foo_topic", b"Hello RT-Thread !!!")
c.disconnect()
if __name__ == "__main__":
main()