史上最简单的C#客户端连接阿里云物联网平台

ゝ一世哀愁。 2022-12-27 11:00 159阅读 0赞

# C\#客户端连接阿里云物联网平台 #

## 创建新项目 Windows窗口应用(.NET Framework) ##

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## 管理NuGet程序包 ##

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## 添加MqttSign.cs ##

using System;
    using System.Security.Cryptography;
    
    namespace WaterSamplePCNet
    { 
        class CryptoUtil
        { 
            public static String hmacSha256(String plainText, String key)
            { 
                var encoding = new System.Text.UTF8Encoding();
                byte[] plainTextBytes = encoding.GetBytes(plainText);
                byte[] keyBytes = encoding.GetBytes(key);
    
                HMACSHA256 hmac = new HMACSHA256(keyBytes);
                byte[] sign = hmac.ComputeHash(plainTextBytes);
                return BitConverter.ToString(sign).Replace("-", string.Empty);
            }
        }
        public class MqttSign
        { 
            private String username = "";
    
            private String password = "";
    
            private String clientid = "";
    
            public String getUsername() {  return this.username; }
    
            public String getPassword() {  return this.password; }
    
            public String getClientid() {  return this.clientid; }
    
            public bool calculate(String productKey, String deviceName, String deviceSecret)
            { 
                if (productKey == null || deviceName == null || deviceSecret == null)
                { 
                    return false;
                }
    
                //MQTT用户名
                this.username = deviceName + "&" + productKey;
    
                //MQTT密码
                String timestamp = Convert.ToInt64((DateTime.UtcNow - new DateTime(1970, 1, 1)).TotalMilliseconds).ToString();
                String plainPasswd = "clientId" + productKey + "." + deviceName + "deviceName" +
                        deviceName + "productKey" + productKey + "timestamp" + timestamp;
                this.password = CryptoUtil.hmacSha256(plainPasswd, deviceSecret);
    
                //MQTT ClientId
                this.clientid = productKey + "." + deviceName + "|" + "timestamp=" + timestamp +
                        ",_v=paho-c#-1.0.0,securemode=2,signmethod=hmacsha256|";
    
                return true;
            }
        }
    }

## 全局变量 ##

string productKey = "a1X2bEn****";
            string deviceName = "example1";
            string deviceSecret = "ga7XA6KdlEeiPXQPpRbAjOZXwG8y****";
            MqttClient mqttClient = null;

## 连接 ##

private void connectBtn_Click(object sender, EventArgs e)
            { 
    
                // 计算MQTT连接参数。
                MqttSign sign = new MqttSign();
                sign.calculate(productKey, deviceName, deviceSecret);
    
                Console.WriteLine("username: " + sign.getUsername());
                Console.WriteLine("password: " + sign.getPassword());
                Console.WriteLine("clientid: " + sign.getClientid());
    
                // 使用Paho连接阿里云物联网平台。
                int port = 443;
                string broker = productKey + ".iot-as-mqtt.cn-shanghai.aliyuncs.com";
    
                mqttClient = new MqttClient(broker, port, true, MqttSslProtocols.TLSv1_2, null, null);
                mqttClient.Connect(sign.getClientid(), sign.getUsername(), sign.getPassword());
    
                Console.WriteLine("Broker: " + broker + " Connected");
            }

## 订阅 ##

private void subscribeBtn_Click(object sender, EventArgs e)
            { 
                // Paho MQTT消息订阅。
                string topicReply = "/sys/" + productKey + "/" + deviceName + "/thing/event/property/post_reply";
    
                mqttClient.MqttMsgPublishReceived += MqttPostProperty_MqttMsgPublishReceived;
                mqttClient.Subscribe(new string[] {  topicReply }, new byte[] {  MqttMsgBase.QOS_LEVEL_AT_MOST_ONCE });
            }
    
            private static void MqttPostProperty_MqttMsgPublishReceived(object sender, uPLibrary.Networking.M2Mqtt.Messages.MqttMsgPublishEventArgs e)
            { 
                Console.WriteLine("reply topic :" + e.Topic);
                Console.WriteLine("reply payload:" + e.Message.ToString());
            }

## 发布 ##

private void publishBtn_Click(object sender, EventArgs e)
            { 
                // Paho MQTT消息发布。
                string topic = "/sys/" + productKey + "/" + deviceName + "/thing/event/property/post";
                string message = "{\"id\":\"1\",\"version\":\"1.0\",\"params\":{\"LightSwitch\":0}}";
                mqttClient.Publish(topic, Encoding.UTF8.GetBytes(message));
            }

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