老范的自言自语 Walter's Solo

EMQ with python

August 31, 2023 by walter

1. start EMQX

docker run -d --name emqx -p 1883:1883 -p 8083:8083 -p 8084:8084 -p 8883:8883 -p 18083:18083 emqx/emqx:latest

2. install paho-mqtt library

pip3 install paho-mqtt

3. start subscriber

import paho.mqtt.client as mqtt
​
# The callback function of connection
def on_connect(client, userdata, flags, rc):
    print(f"Connected with result code {rc}")
    client.subscribe("$SYS/#")

# The callback function for received message
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("broker.emqx.io", 1883, 60)
client.loop_forever()

4. start publisher

import paho.mqtt.client as mqtt
import time
def on_connect(client, userdata, flags, rc):
    print(f"Connected with result code {rc}")

client = mqtt.Client()
client.on_connect = on_connect
client.connect("broker.emqx.io", 1883, 60)
for i in range(3):
    client.publish('a/b', payload=i, qos=0, retain=False)
    print(f"send {i} to a/b")
    time.sleep(1)
​
client.loop_forever()

or

import paho.mqtt.subscribe as subscribe
​
# When this function is called, the program will block here until a message is sent to the topic paho/test/simple
msg = subscribe.simple("paho/test/simple", hostname="broker.emqx.io")
print(f"{msg.topic} {msg.payload}")
import paho.mqtt.publish as publish
​
# Send a message
publish.single("a/b", "payload", hostname="broker.emqx.io")
# Or send multiple messages at once
msgs = [{'topic':"a/b", 'payload':"multiple 1"}, ("a/b", "multiple 2", 0, False)]
publish.multiple(msgs, hostname="broker.emqx.io")

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