【Go】mqtt连接、监听、发送_golang 监听mqtt

import (
	"context"
	"fmt"
	mqtt "github.com/eclipse/paho.mqtt.golang"
)

var messageRecHandler mqtt.MessageHandler = func(client mqtt.Client, msg mqtt.Message) {
	fmt.Printf("Received message: %s from topic: %s\n", msg.Payload(), msg.Topic())
}

var messagePubHandler mqtt.MessageHandler = func(client mqtt.Client, msg mqtt.Message) {
	fmt.Printf("Publish message: %s from topic: %s\n", msg.Payload(), msg.Topic())
}

var connectHandler mqtt.OnConnectHandler = func(client mqtt.Client) {
	fmt.Println("Connected")
}

var connectLostHandler mqtt.ConnectionLostHandler = func(client mqtt.Client, err error) {
	fmt.Printf("Connect lost: %v", err)
}

func main() {
	var broker = "localhost"
	var port = 1883
	opts := mqtt.NewClientOptions()
	opts.AddBroker(fmt.Sprintf("tcp://%s:%d", broker, port))
	opts.SetClientID("dev")
	opts.SetUsername("guest")
	opts.SetPassword("guest")
	opts.SetDefaultPublishHandler(messagePubHandler)
	opts.OnConnect = connectHandler
	opts.OnConnectionLost = connectLostHandler
	client := mqtt.NewClient(opts)
	if token := client.Connect(); token.Wait() && token.Error() != nil {
		panic(token.Error())
	}

	client.Publish("xx-topic", 1, true, `{"from":123}`)
	client.Subscribe("xx-topic", 1, messageRecHandler)
	<-context.Background().Done()
}

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