.CORE 5 Web Api 和客戶端MQTT

Question

是否可以創建 a.core webapi 項目和 mqtt 客戶端？ 例如，在 startup.cs 中創建一個單獨的線程，您可以在其中實例化一個 mqtt 客戶端

Answer 1

我嘗試添加一個 Singleton 服務來在 startup.cs 中實例化 mqtt 客戶端，它工作正常，程序接收主題上發布的消息。 第一個問題，在這個位置創建這個服務是否正確？

問題是當我嘗試使用 package 控制台工具添加數據庫的遷移或更新時。 該命令未完成排序並且控制台被鎖定。

        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllers();
            services.AddDbContext<ApplicationDbContext>(options => options.UseSqlServer("name=ConnectionStrings:DefaultConnection"));
            services.AddSingleton<MyMqtt>(new MyMqtt());
            services.AddSwaggerGen(c =>
            {
                c.SwaggerDoc("v1", new OpenApiInfo { Title = "CoWorkOfficeWebApi", Version = "v1" });
            });
        }

Class

    public class MyMqtt
    {
        MqttClient client;

        public MyMqtt()
        {
            // create client instance 
            client = new MqttClient("127.0.0.1");
            // register to message received 
            client.MqttMsgPublishReceived += client_MqttMsgPublishReceived;
            string clientId = Guid.NewGuid().ToString();
            client.Connect(clientId);
            // subscribe to the topic "/home/temperature" with QoS 2 
            client.Subscribe(new string[] { "/home/temperature" }, new byte[] { MqttMsgBase.QOS_LEVEL_EXACTLY_ONCE });
        }


        static void client_MqttMsgPublishReceived(object sender, MqttMsgPublishEventArgs e)
        {
            string msg = Encoding.UTF8.GetString(e.Message);
            Console.WriteLine($"Topic: {e.Topic}, Message: {msg}");
        }
    }