如何在 SignalR Hub C# 中接收 UDP 套接字数据

Question

我在我的 Web 项目中使用 SignalR 创建了一个集线器。在我的集线器类中，我想接收在端口号 4001 上发送的 udp 数据。请建议通过 udp 套接字接收数据的代码。我尝试使用如下所示的代码接收，但它给出了错误“System.Net.Sockets.SocketException：'通常只允许每个套接字地址（协议/网络地址/端口）的一次使用”

ClockHub.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using Microsoft.AspNet.SignalR;

namespace RealTimeClock.App_Code
{
    public class ClockHub : Hub
    {
        public void getSocketData()
        {     
       // Here I want to receive udp socket data  on port 4001 

        // my code commented here did not work
            //UdpClient receivingUdpClient = new UdpClient(11000); 
            //IPEndPoint RemoteIpEndPoint = new IPEndPoint(IPAddress.Any, 0);
            //Byte[] receiveBytes = receivingUdpClient.Receive(ref RemoteIpEndPoint);
            //string UDP_Rx_Data= Encoding.ASCII.GetString   rceiveBytes);  



            
            Clients.Caller.setTime(UDP_Rx_Data);
        }
    }
}

Answer 1

您可以使用中介应用程序接收 UDP 数据包，然后将它们转发到 SignalR Hub。

可以使用任务计划程序设置为自动重启的中间应用程序：

using Microsoft.AspNet.SignalR.Client;
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

namespace UdpToSignalR
{
    internal class Program
    {
        private static readonly string hubURL = System.Configuration.ConfigurationManager.AppSettings["HubURL"];
        private static readonly int listenPort = int.Parse(System.Configuration.ConfigurationManager.AppSettings["UDPPort"]);

        private static void StartListener(IHubProxy hub)
        {
            UdpClient listener = new UdpClient(listenPort);
            IPEndPoint groupEP = new IPEndPoint(IPAddress.Any, listenPort);

            try
            {
                while (true)
                {
                    byte[] bytes = listener.Receive(ref groupEP);
                    hub.Invoke("getSocketData", Encoding.ASCII.GetString(bytes, 0, bytes.Length));
                }
            }
            catch (SocketException e)
            {
                Console.WriteLine(e);
            }
            finally
            {
                listener.Close();
                Environment.Exit(0);
            }
        }

        public static void Main()
        {

            HubConnection connection = new HubConnection(hubURL);
            var hub = connection.CreateHubProxy("ClockHub");
            connection.StateChanged += (state) =>
            {
                Console.WriteLine($"State Changed: {state.NewState}");
            };
            connection.Reconnecting += () =>
            {
                Console.WriteLine("Reconnecting....");
            };
            connection.Closed += () =>
            {
                // If we loose hub connection close the app so that the task scheduler can fire it up again.
                Environment.Exit(0);
            };
            connection.Start().Wait();

            StartListener(hub);

        }
    }
}

此代码从应用程序配置中获取您的集线器 url 和 UDP 端口：

<appSettings>
    <add key="UDPPort" value="4001"/>
    <add key="HubURL" value="http://localhost:54856/signalr"/>
</appSettings>

您的中心代码将是：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using Microsoft.AspNet.SignalR;

namespace RealTimeClock.App_Code
{
    public class ClockHub : Hub
    {
        public Task getSocketData(string message)
        {     
            Clients.Caller.setTime(message);
        }
    }
}