阿里雲上通過MQTT協議，實現多設備的相互數據的穩定動態傳輸和使用（本地設備均採用c#窗體代碼）第二篇-----本地設備開發（Demo)

引言

  本段代碼的含義在之前的一篇文章裏有介紹，本文爲完整代碼的展示，之前介紹用的文章，點擊此處即可查看

Demo代碼：

using System;
using System.Net;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using uPLibrary.Networking.M2Mqtt;
using uPLibrary.Networking.M2Mqtt.Messages;
using System.Windows.Forms;
using System.Security.Cryptography;
namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        //阿里雲的數據
        static string ProductKey = "***";//輸入自己的ProductKey
        static string DeviceName = "***";//輸入自己的DeviceName
        static string DeviceSecret = "***";//輸入自己的DeviceSecret
        static string RegionId = "cn-shanghai";
        static string PubTopic = "/" + ProductKey + "/" + DeviceName + "/user/update";
        static string SubTopic = "/" + ProductKey + "/" + DeviceName + "/user/get";
        public Form1()
        {
            InitializeComponent();
            System.Windows.Forms.Control.CheckForIllegalCrossThreadCalls = false;
        }
        private void label1_Click(object sender, EventArgs e)
        {

        }
        private void button1_Click(object sender, EventArgs e)
        {
            label3.Text = "數據已經上傳！";
            //開始連接阿里雲
            IPHostEntry host = Dns.GetHostEntry(Dns.GetHostName());
            string clientId = host.AddressList.FirstOrDefault(
                ip => ip.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork).ToString();
            string t = Convert.ToString(DateTimeOffset.Now.ToUnixTimeMilliseconds());
            string signmethod = "hmacmd5";
            Dictionary<string, string> dict = new Dictionary<string, string>();
            dict.Add("productKey", ProductKey);
            dict.Add("deviceName", DeviceName);
            dict.Add("clientId", clientId);
            dict.Add("timestamp", t);
            string mqttUserName = DeviceName + "&" + ProductKey;
            string mqttPassword = IotSignUtils.sign(dict, DeviceSecret, signmethod);
            string mqttClientId = clientId + "|securemode=3,signmethod=" + signmethod + ",timestamp=" + t + "|";
            string targetServer = ProductKey + ".iot-as-mqtt." + RegionId + ".aliyuncs.com";
            ConnectMqtt(targetServer, mqttClientId, mqttUserName, mqttPassword);
        }
        public void ConnectMqtt(string targetServer, string mqttClientId, string mqttUserName, string mqttPassword)
        {
            MqttClient client = new MqttClient(targetServer);
            client.ProtocolVersion = MqttProtocolVersion.Version_3_1_1;

            client.Connect(mqttClientId, mqttUserName, mqttPassword, false, 60);
            client.MqttMsgPublishReceived += Client_MqttMsgPublishReceived;

            //訂閱消息
            client.Subscribe(new string[] { SubTopic }, new byte[] { 0 });

            //發佈消息,發佈的消息爲我們在textBox1上的Text
            String content = textBox1.Text;
            //他上傳的數據需要時byte[],所以我們先需要將string類轉換成byte[]
            byte[] by1 = System.Text.Encoding.ASCII.GetBytes(content);
            var id = client.Publish(PubTopic, by1);
        }
        public void Client_MqttMsgPublishReceived(object sender, MqttMsgPublishEventArgs e)
        {
            //對獲得的message的處理
            string topic = e.Topic;
            string message = Encoding.ASCII.GetString(e.Message);//從被訂閱端獲取消息
            int length = message.Length;//我們先得到這條message的長度，
            //因爲是string所以調用他的length函數就可以了
            label2.Text = message.Substring(0, length);//label3原先是null，
            //後來就會變成message的內容，從頭開始讀，長度就是length
        }
    }
    public class IotSignUtils//簽名文件
    {
        public static string sign(Dictionary<string, string> param,
                            string deviceSecret, string signMethod)
        {
            string[] sortedKey = param.Keys.ToArray();
            Array.Sort(sortedKey);

            StringBuilder builder = new StringBuilder();
            foreach (var i in sortedKey)
            {
                builder.Append(i).Append(param[i]);
            }

            byte[] key = Encoding.UTF8.GetBytes(deviceSecret);
            byte[] signContent = Encoding.UTF8.GetBytes(builder.ToString());
            //這裏根據signMethod對代碼進行了一些動態調整，於是寫了一個HMACMD5
            var hmac = new HMACMD5(key);
            byte[] hashBytes = hmac.ComputeHash(signContent);

            StringBuilder signBuilder = new StringBuilder();
            foreach (byte b in hashBytes)
                signBuilder.AppendFormat("{0:x2}", b);

            return signBuilder.ToString();
        }
    }
}