MQTT - 1. 使用免費公開的 MQTT Broker Server 學習如何訂閱、發行(收發資料)

MQTT 客户端整个生命周期的行为可以概括为：建立连接、订阅主题、接收消息并处理、向指定主题发布消息、取消订阅、断开连接。

1	MQTT 客户端整个生命周期的行为可以概括为：建立连接、订阅主题、接收消息并处理、向指定主题发布消息、取消订阅、断开连接。

節錄： MQTT 客户端库

公開 MQTT Borker

The Free Global Public MQTT Broker | Try Now | EMQ (emqx.com) - broker.emqx.io:1883
The Public MQTT Broker by HiveMQ - Check out our MQTT Demo - broker.hivemq.com:1883
HiveMQ Dashboard (mqtt-dashboard.com) HiveMQ 監控
test.mosquitto.org - test.mosquitto.org:1883
Sandboxes | IoT development made simple - mqtt.eclipse.org:1883

建議選擇 broker.emqx.io 或 broker.hivemq.com，這兩台主機同時支援 WebSocket 和 SSL 才可以測試網頁 WebSocket 和 MQTT 的通訊

程式參考

Simple Python MQTT Publish and Subscribe Example Script

以下 Python 範例程式已經根據可用 MQTT Broker 修改

程式先訂閱 house/bulb1 主題，然後發行 house/bulb1 此主題及內容

import time
import paho.mqtt.client as paho

broker = "broker.emqx.io"

# define callback
def on_message(client, userdata, message):
    time.sleep(1)
    print("received message =", str(message.payload.decode("utf-8")))

client = paho.Client("client-001")  # create client object client1.on_publish = on_publish #assign function to callback client1.connect(broker,port) #establish connection client1.publish("house/bulb1","on")
######Bind function to callback
client.on_message = on_message
#####
print("connecting to broker ", broker)
client.connect(broker)  # connect
client.loop_start()  # start loop to process received messages
print("subscribing ")
client.subscribe("house/bulb1")  # subscribe
print("publishing ")
client.publish("house/bulb1", "on")  # publish
time.sleep(3)
client.disconnect()  # disconnect
client.loop_stop()  # stop loop

import time

import paho.mqtt.client as paho

broker = "broker.emqx.io"

# define callback

def on_message(client, userdata, message):

time.sleep(1)

print("received message =", str(message.payload.decode("utf-8")))

client = paho.Client("client-001") # create client object client1.on_publish = on_publish #assign function to callback client1.connect(broker,port) #establish connection client1.publish("house/bulb1","on")

######Bind function to callback

client.on_message = on_message

#####

print("connecting to broker ", broker)

client.connect(broker) # connect

client.loop_start() # start loop to process received messages

print("subscribing ")

client.subscribe("house/bulb1") # subscribe

print("publishing ")

client.publish("house/bulb1", "on") # publish

time.sleep(3)

client.disconnect() # disconnect

client.loop_stop() # stop loop

運作結果

connecting to broker  broker.emqx.io
subscribing 
publishing 
received message = on

connecting to broker broker.emqx.io

subscribing

publishing

received message = on

Topic 萬用字元

MQTT(五)SUBSCRIBE Message

finance/stock/ibm/#

finance/stock/ibm
finance/stock/ibm/closingprice
finance/stock/ibm/currentprice

finance/stock/ibm/#

finance/stock/ibm

finance/stock/ibm/closingprice

finance/stock/ibm/currentprice

finance/stock/+
/finance/stock/ibm
/finance/stock/xyz

不匹配
/finance/stock/ibm/closingprice

finance/stock/+

/finance/stock/ibm

/finance/stock/xyz

不匹配

/finance/stock/ibm/closingprice

Workerman Socket VS MQTT

MQTT 要接收的資料必須自己訂閱，少了多了都有問題，Socket 要自己處理資料流
傳送時斷線 Socket 就是失敗，MQTT 根據 QoS 政策可以保證資料的送達。當 QoS 為 0 時，短暫的斷線 (拔網路線10秒) 也能成功送達
主機端須處理的程式 Socket 可以寫在 Workerman 內，MQTT 因為 Server 只是代理，所以程式必須分開，以健康度來說 MQTT 較佳；Socket 程式一致性及即時性較佳

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MQTT - 1. 使用免費公開的 MQTT Broker Server 學習如何訂閱、發行(收發資料)

公開 MQTT Borker

程式參考

Topic 萬用字元

Workerman Socket VS MQTT

Related Post

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MQTT - 1. 使用免費公開的 MQTT Broker Server 學習如何訂閱、發行(收發資料)

公開 MQTT Borker

程式參考

Topic 萬用字元

Workerman Socket VS MQTT

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