C#编写上位机连接华为云平台IoTDA

需求

我们在平时的物联网开发中，往往需要用到云平台来收发数据。而光有云平台往往是不行的，我们还需要有上位机。那么怎样通过上位机连接到云平台，并且收发数据呢？本文将介绍如何通过C#编写的上位机和华为云平台通过物联网最常用MQTT协议进行连接并收发数据。介绍设备通MQTTS/MQTT协议接入平台，通过平台接口实现“数据上报”、“命令下发”的功能。

前期准备

1. VS2019
2. 华为云平台

具体设计 代码目录简述：

1. App.config：Server地址和设备信息配置文件
2. C#：项目C#代码；
3. EncryptUtil.cs：设备密钥加密辅助类；
4. FrmMqttDemo.cs：窗体界面；
5. Program.cs：Demo程序启动入口。
6. dll：项目中使用到了第三方库
7. MQTTnet：v3.0.11，是一个基于 MQTT 通信的高性能 .NET 开源库，它同时支持MQTT 服务器端和客户端，引用库文件包含MQTTnet.dll。
8. MQTTnet.Extensions.ManagedClient：v3.0.11，这是一个扩展库，它使用MQTTnet为托管MQTT客户机提供附加功能。

工程配置参数

App.config：需要配置服务器地址、设备ID和设备密钥，用于启动Demo程序的时 候，程序将此信息自动写到Demo主界面。

<add key="serverUri" value="serveruri"/> <add key="deviceId" value="deviceid"/> <add key="deviceSecret" value="secret"/> <add key="PortIsSsl" value="8883"/> <add key="PortNotSsl" value="1883"/> 

具体程序 App.config

本文件中存放的是Server地址和设备信息配置文件，我们每个人的程序主要的不同就是这个文件，虽然后面也可以在运行的时候改，但最好提前写入。

<?xml version="1.0" encoding="utf-8"?> <configuration> <configSections> </configSections> <startup> <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5.2"/> </startup> <appSettings> <add key="serverUri" value="iot-mqtts.cn-north-4.myhuaweicloud.com"/> <add key="deviceId" value="自己的设备ID"/> <add key="deviceSecret" value="自己的设备密钥"/> <add key="portIsSsl" value="8883"/> <add key="portNotSsl" value="1883"/> <add key="language" value="zh-CN"/> </appSettings> </configuration> 

我们将自己的自己的设备ID和自己的设备密钥填入其中，选择相应的语言，最好填中文，毕竟看的方便。

主程序 连接服务器

try { int portIsSsl = int.Parse(ConfigurationManager.AppSettings["portIsSsl"]); int portNotSsl = int.Parse(ConfigurationManager.AppSettings["portNotSsl"]); if (client == null) { client = new MqttFactory().CreateManagedMqttClient(); } string timestamp = DateTime.Now.ToString("yyyyMMddHH"); string clientID = txtDeviceId.Text + "_0_0_" + timestamp; // 对密码进行HmacSHA256加密 string secret = string.Empty; if (!string.IsNullOrEmpty(txtDeviceSecret.Text)) { secret = EncryptUtil.HmacSHA256(txtDeviceSecret.Text, timestamp); } // 判断是否为安全连接 if (!cbSSLConnect.Checked) { options = new ManagedMqttClientOptionsBuilder() .WithAutoReconnectDelay(TimeSpan.FromSeconds(RECONNECT_TIME)) .WithClientOptions(new MqttClientOptionsBuilder() .WithTcpServer(txtServerUri.Text, portNotSsl) .WithCommunicationTimeout(TimeSpan.FromSeconds(DEFAULT_CONNECT_TIMEOUT)) .WithCredentials(txtDeviceId.Text, secret) .WithClientId(clientID) .WithKeepAlivePeriod(TimeSpan.FromSeconds(DEFAULT_KEEPLIVE)) .WithCleanSession(false) .WithProtocolVersion(MqttProtocolVersion.V311) .Build()) .Build(); } else { string caCertPath = Environment.CurrentDirectory + @"\certificate\rootcert.pem"; X509Certificate2 crt = new X509Certificate2(caCertPath); options = new ManagedMqttClientOptionsBuilder() .WithAutoReconnectDelay(TimeSpan.FromSeconds(RECONNECT_TIME)) .WithClientOptions(new MqttClientOptionsBuilder() .WithTcpServer(txtServerUri.Text, portIsSsl) .WithCommunicationTimeout(TimeSpan.FromSeconds(DEFAULT_CONNECT_TIMEOUT)) .WithCredentials(txtDeviceId.Text, secret) .WithClientId(clientID) .WithKeepAlivePeriod(TimeSpan.FromSeconds(DEFAULT_KEEPLIVE)) .WithCleanSession(false) .WithTls(new MqttClientOptionsBuilderTlsParameters() { AllowUntrustedCertificates = true, UseTls = true, Certificates = new List<X509Certificate> { crt }, CertificateValidationHandler = delegate { return true; }, IgnoreCertificateChainErrors = false, IgnoreCertificateRevocationErrors = false }) .WithProtocolVersion(MqttProtocolVersion.V311) .Build()) .Build(); } Invoke((new Action(() => { ShowLogs($"{"try to connect to server " + txtServerUri.Text}{Environment.NewLine}"); }))); if (client.IsStarted) { await client.StopAsync(); } // 注册事件 client.ApplicationMessageProcessedHandler = new ApplicationMessageProcessedHandlerDelegate(new Action<ApplicationMessageProcessedEventArgs>(ApplicationMessageProcessedHandlerMethod)); // 消息发布回调 client.ApplicationMessageReceivedHandler = new MqttApplicationMessageReceivedHandlerDelegate(new Action<MqttApplicationMessageReceivedEventArgs>(MqttApplicationMessageReceived)); // 命令下发回调 client.ConnectedHandler = new MqttClientConnectedHandlerDelegate(new Action<MqttClientConnectedEventArgs>(OnMqttClientConnected)); // 连接成功回调 client.DisconnectedHandler = new MqttClientDisconnectedHandlerDelegate(new Action<MqttClientDisconnectedEventArgs>(OnMqttClientDisconnected)); // 连接断开回调 // 连接平台设备 await client.StartAsync(options); } catch (Exception ex) { Invoke((new Action(() => { ShowLogs($"connect to mqtt server fail" + Environment.NewLine); }))); } 

接收到消息

Invoke((new Action(() => { ShowLogs($"received message is {Encoding.UTF8.GetString(e.ApplicationMessage.Payload)}{Environment.NewLine}"); string msg = "{\"result_code\": 0,\"response_name\": \"COMMAND_RESPONSE\",\"paras\": {\"result\": \"success\"}}"; string topic = "$oc/devices/" + txtDeviceId.Text + "/sys/commands/response/request_id=" + e.ApplicationMessage.Topic.Split('=')[1]; ShowLogs($"{"response message msg = " + msg}{Environment.NewLine}"); var appMsg = new MqttApplicationMessage(); appMsg.Payload = Encoding.UTF8.GetBytes(msg); appMsg.Topic = topic; appMsg.QualityOfServiceLevel = int.Parse(cbOosSelect.SelectedValue.ToString()) == 0 ? MqttQualityOfServiceLevel.AtMostOnce : MqttQualityOfServiceLevel.AtLeastOnce; appMsg.Retain = false; // 上行响应 client.PublishAsync(appMsg).Wait(); }))); 

消息发布回调

try { if (e.HasFailed) { Invoke((new Action(() => { ShowLogs("publish messageId is " + e.ApplicationMessage.Id + ", topic: " + e.ApplicationMessage.ApplicationMessage.Topic + ", payload: " + Encoding.UTF8.GetString(e.ApplicationMessage.ApplicationMessage.Payload) + " is published fail"); }))); } else if (e.HasSucceeded) { Invoke((new Action(() => { ShowLogs("publish messageId " + e.ApplicationMessage.Id + ", topic: " + e.ApplicationMessage.ApplicationMessage.Topic + ", payload: " + Encoding.UTF8.GetString(e.ApplicationMessage.ApplicationMessage.Payload) + " is published success"); }))); } } catch (Exception ex) { Invoke((new Action(() => { ShowLogs("mqtt demo message publish error: " + ex.Message + Environment.NewLine); }))); } 

服务器连接成功

Invoke((new Action(() => { ShowLogs("connect to mqtt server success, deviceId is " + txtDeviceId.Text + Environment.NewLine); btnConnect.Enabled = false; btnDisconnect.Enabled = true; btnPublish.Enabled = true; btnSubscribe.Enabled = true; }))); 

断开服务器连接

try { Invoke((new Action(() => { ShowLogs("mqtt server is disconnected" + Environment.NewLine); txtSubTopic.Enabled = true; btnConnect.Enabled = true; btnDisconnect.Enabled = false; btnPublish.Enabled = false; btnSubscribe.Enabled = false; }))); if (cbReconnect.Checked) { Invoke((new Action(() => { ShowLogs("reconnect is starting" + Environment.NewLine); }))); //退避重连 int lowBound = (int)(defaultBackoff * 0.8); int highBound = (int)(defaultBackoff * 1.2); long randomBackOff = random.Next(highBound - lowBound); long backOffWithJitter = (int)(Math.Pow(2.0, retryTimes)) * (randomBackOff + lowBound); long waitTImeUtilNextRetry = (int)(minBackoff + backOffWithJitter) > maxBackoff ? maxBackoff : (minBackoff + backOffWithJitter); Invoke((new Action(() => { ShowLogs("next retry time: " + waitTImeUtilNextRetry + Environment.NewLine); }))); Thread.Sleep((int)waitTImeUtilNextRetry); retryTimes++; Task.Run(async () => { await ConnectMqttServerAsync(); }); } } catch (Exception ex) { Invoke((new Action(() => { ShowLogs("mqtt demo error: " + ex.Message + Environment.NewLine); }))); } 

格式

设备端上传到云平台 Topic：$oc/devices/{device_id}/sys/properties/report 数据格式：

数据格式： { "services": [{ "service_id": "Temperature", "properties": { "smoke": 57, "temperature": 60, "humidity":78.37673 }, "event_time": "20151212T121212Z" } ] } 

运行界面

当我发送如下数据时：

{ "services": [{ "service_id": "BS", "properties": { "smoke": 57, "temperature": 60, "humidity":78.37673 }, "event_time": "20151212T121212Z" } ] } 

后续

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编写不易，感谢支持。