go实现mqtt、golang实现物联网、go实现物联网MQTT、IoT

一、创建MQTT平台服务

免费创建网址：https://cloud.emqx.cn/
或者使用开放免费：

broker: broker.emqx.io
port: 1833
ClientID: go_mqtt_client
Username: emqx
Password: public

二、实现方式（支持 mqtt、mqtts、ws、wss）协议

案例1：

package main

import (
	"fmt"
	"sync"
	"time"

	mqtt "github.com/eclipse/paho.mqtt.golang"
)

//12847(mqtt), 12173(mqtts), 8083(ws), 8084(wss)
const broker = "tcp://tee2b1be.cn.emqx.cloud:12847"
const username = "xhcomvip"
const password = ""
const ClientID = "go_mqtt_client"

//message的回调
var onMessage mqtt.MessageHandler = func(client mqtt.Client, msg mqtt.Message) {
	fmt.Printf("[%s] -> %s\n", msg.Topic(), msg.Payload())
}

var wg sync.WaitGroup
var client mqtt.Client

func main() {
	//连接MQTT服务器
	mqttConnect()
	defer client.Disconnect(250) //注册销毁
	wg.Add(1)
	go mqttSubScribe("topic/test")
	wg.Add(1)
	go testPublish()
	wg.Wait()
}
func mqttConnect() {
	//配置
	clinetOptions := mqtt.NewClientOptions().AddBroker(broker).SetUsername(username).SetPassword(password)
	clinetOptions.SetClientID(ClientID)
	clinetOptions.SetConnectTimeout(time.Duration(60) * time.Second)
	//连接
	client = mqtt.NewClient(clinetOptions)
	//客户端连接判断
	if token := client.Connect(); token.WaitTimeout(time.Duration(60)*time.Second) && token.Wait() && token.Error() != nil {
		panic(token.Error())
	}
}

func mqttSubScribe(topic string) {
	defer wg.Done()
	for {
		token := client.Subscribe(topic, 1, onMessage)
		token.Wait()
	}
}

//测试 3秒发送一次，然后自己接收
func testPublish() {
	defer wg.Done()
	for {
		client.Publish("topic/test", 1, false, "TEST")
		time.Sleep(time.Duration(3) * time.Second)
	}
}

案例2：

package main

import (
	"crypto/tls"
	"crypto/x509"
	"fmt"
	"io/ioutil"
	"log"
	"time"

	mqtt "github.com/eclipse/paho.mqtt.golang"
)

var messagePubHandler mqtt.MessageHandler = func(client mqtt.Client, msg mqtt.Message) {
	fmt.Printf("Received 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)
}

//https://cloud.emqx.cn/console/deployments/0?oper=new
// ClientOptions：用于设置 broker，端口，客户端 id ，用户名密码等选项
// messagePubHandler：全局 MQTT pub 消息处理
// connectHandler：连接的回调
// connectLostHandler：连接丢失的回调
func main() {
	var broker = "broker.emqx.io"
	var port = 1883
	opts := mqtt.NewClientOptions()
	opts.AddBroker(fmt.Sprintf("tcp://%s:%d", broker, port))
	opts.SetClientID("go_mqtt_client")
	opts.SetUsername("emqx")
	opts.SetPassword("public")
	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())
	}
	sub(client)
	publish(client)
	client.Disconnect(250)
}

//发布消息
func publish(client mqtt.Client) {
	num := 10
	for i := 0; i < num; i++ {
		text := fmt.Sprintf("Message %d", i)
		token := client.Publish("topic/test", 0, false, text)
		token.Wait()
		time.Sleep(time.Second)
	}
}

//订阅
func sub(client mqtt.Client) {
	topic := "topic/test"
	token := client.Subscribe(topic, 1, nil)
	token.Wait()
	fmt.Printf("Subscribed to topic: %s", topic)
}

//如果想使用 TLS 连接，可以如下设置：
func NewTlsConfig() *tls.Config {
	certpool := x509.NewCertPool()
	ca, err := ioutil.ReadFile("ca.pem")
	if err != nil {
		log.Fatalln(err.Error())
	}
	certpool.AppendCertsFromPEM(ca)
	// Import client certificate/key pair
	clientKeyPair, err := tls.LoadX509KeyPair("client-crt.pem", "client-key.pem")
	if err != nil {
		panic(err)
	}
	return &tls.Config{
		RootCAs:            certpool,
		ClientAuth:         tls.NoClientCert,
		ClientCAs:          nil,
		InsecureSkipVerify: true,
		Certificates:       []tls.Certificate{clientKeyPair},
	}
}

//如果不设置客户端证书，可以如下设置：
func NewTlsConfigs() *tls.Config {
	certpool := x509.NewCertPool()
	ca, err := ioutil.ReadFile("ca.pem")
	if err != nil {
		log.Fatalln(err.Error())
	}
	certpool.AppendCertsFromPEM(ca)
	return &tls.Config{
		RootCAs:            certpool,
		ClientAuth:         tls.NoClientCert,
		ClientCAs:          nil,
		InsecureSkipVerify: true,
	}
}

案例3：

package main

import (
	"crypto/tls"
	"crypto/x509"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"time"

	mqtt "github.com/eclipse/paho.mqtt.golang"
)

type Config struct {
	Host     string
	Port     int
	Action   string
	Topic    string
	Username string
	Password string
	Qos      int
	Tls      bool
	CaCert   string
}

var Host = flag.String("host", "broker.emqx.io", "server hostname or IP")
var Port = flag.Int("port", 1883, "server port")
var Action = flag.String("action", "pubsub", "pub/sub/pubsub action")
var Protocol = flag.String("protocol", "mqtt", "mqtt/mqtts/ws/wss")
var Topic = flag.String("topic", "golang-mqtt/test", "publish/subscribe topic")
var Username = flag.String("username", "emqx", "username")
var Password = flag.String("password", "public", "password")
var Qos = flag.Int("qos", 0, "MQTT QOS")
var Tls = flag.Bool("tls", false, "Enable TLS/SSL")
var CaCert = flag.String("cacert", "./broker.emqx.io-ca.crt", "tls cacert")

func main() {
	flag.Parse()
	config := Config{Host: *Host, Port: *Port, Action: *Action, Topic: *Topic, Username: *Username, Password: *Password, Qos: *Qos, Tls: *Tls, CaCert: *CaCert}
	protocol := *Protocol
	switch protocol {
	case "mqtt":
		MQTTConnection(config)
	case "mqtts":
		MQTTSConnection(config)
	case "ws":
		WSConnection(config)
	case "wss":
		WSSConnection(config)
	default:
		log.Fatalf("Unsupported protocol: %s", protocol)
	}
}

func Pub(client mqtt.Client, topic string) {
	pubClient := client
	i := 1
	for {
		payload := fmt.Sprintf("%d", i)
		pubClient.Publish(topic, 0, false, payload)
		log.Printf("pub [%s] %s\n", topic, payload)
		//i += 1
		i++
		time.Sleep(1 * time.Second)
	}
}

func Sub(client mqtt.Client, topic string) {
	subClient := client
	subClient.Subscribe(topic, 0, func(subClient mqtt.Client, msg mqtt.Message) {
		log.Printf("sub [%s] %s\n", msg.Topic(), string(msg.Payload()))
	})
	for {
		time.Sleep(1 * time.Second)
	}
}

func PubSub(client mqtt.Client, topic string) {
	go Sub(client, topic)
	Pub(client, topic)
}

func connectByMQTT(config Config) mqtt.Client {
	opts := mqtt.NewClientOptions()
	broker := fmt.Sprintf("tcp://%s:%d", config.Host, config.Port)
	opts.AddBroker(broker)
	opts.SetUsername(config.Username)
	opts.SetPassword(config.Password)
	client := mqtt.NewClient(opts)
	token := client.Connect()
	for !token.WaitTimeout(3 * time.Second) {
	}
	if err := token.Error(); err != nil {
		log.Fatal(err)
	}
	return client
}

func connectByMQTTS(config Config) mqtt.Client {
	var tlsConfig tls.Config
	if config.Tls && config.CaCert == "" {
		log.Fatalln("TLS field in config is required")
	}
	certpool := x509.NewCertPool()
	ca, err := ioutil.ReadFile(config.CaCert)
	if err != nil {
		log.Fatalln(err.Error())
	}
	certpool.AppendCertsFromPEM(ca)
	tlsConfig.RootCAs = certpool

	opts := mqtt.NewClientOptions()
	broker := fmt.Sprintf("ssl://%s:%d", config.Host, config.Port)
	println(broker)
	opts.AddBroker(broker)
	opts.SetUsername(config.Username)
	opts.SetPassword(config.Password)
	opts.SetTLSConfig(&tlsConfig)
	client := mqtt.NewClient(opts)
	token := client.Connect()
	for !token.WaitTimeout(3 * time.Second) {
	}
	if err := token.Error(); err != nil {
		log.Fatal(err)
	}
	return client
}

func connectByWS(config Config) mqtt.Client {
	opts := mqtt.NewClientOptions()
	broker := fmt.Sprintf("ws://%s:%d/mqtt", config.Host, config.Port)
	opts.AddBroker(broker)
	opts.SetUsername(config.Username)
	opts.SetPassword(config.Password)
	client := mqtt.NewClient(opts)
	token := client.Connect()
	for !token.WaitTimeout(3 * time.Second) {
	}
	if err := token.Error(); err != nil {
		log.Fatal(err)
	}
	return client
}

func connectByWSS(config Config) mqtt.Client {
	var tlsConfig tls.Config
	if config.Tls && config.CaCert == "" {
		log.Fatalln("TLS field in config is required")
	}
	certpool := x509.NewCertPool()
	ca, err := ioutil.ReadFile(config.CaCert)
	if err != nil {
		log.Fatalln(err.Error())
	}
	certpool.AppendCertsFromPEM(ca)
	tlsConfig.RootCAs = certpool

	opts := mqtt.NewClientOptions()
	broker := fmt.Sprintf("wss://%s:%d/mqtt", config.Host, config.Port)
	opts.AddBroker(broker)
	opts.SetUsername(config.Username)
	opts.SetPassword(config.Password)
	opts.SetTLSConfig(&tlsConfig)
	client := mqtt.NewClient(opts)
	token := client.Connect()
	for !token.WaitTimeout(3 * time.Second) {
	}
	if err := token.Error(); err != nil {
		log.Fatal(err)
	}
	return client
}

func MQTTSConnection(config Config) {
	client := connectByMQTTS(config)
	action := config.Action
	switch action {
	case "pub":
		Pub(client, config.Topic)
	case "sub":
		Sub(client, config.Topic)
	case "pubsub":
		PubSub(client, config.Topic)
	default:
		log.Fatalf("Unsupported action: %s", action)
	}
}

func MQTTConnection(config Config) {
	client := connectByMQTT(config)
	action := config.Action
	switch action {
	case "pub":
		Pub(client, config.Topic)
	case "sub":
		Sub(client, config.Topic)
	case "pubsub":
		PubSub(client, config.Topic)
	default:
		log.Fatalf("Unsupported action: %s", action)
	}
}

func WSConnection(config Config) {
	client := connectByWS(config)
	action := config.Action
	switch action {
	case "pub":
		Pub(client, config.Topic)
	case "sub":
		Sub(client, config.Topic)
	case "pubsub":
		PubSub(client, config.Topic)
	default:
		log.Fatalf("Unsupported action: %s", action)
	}
}

func WSSConnection(config Config) {
	client := connectByWSS(config)
	action := config.Action
	switch action {
	case "pub":
		Pub(client, config.Topic)
	case "sub":
		Sub(client, config.Topic)
	case "pubsub":
		PubSub(client, config.Topic)
	default:
		log.Fatalf("Unsupported action: %s", action)
	}
}

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