.net 6 怎么实现WebSocket主机代码

在 .NET 6 中，可以使用 System.Net.WebSockets 命名空间中的类来实现 WebSocket 主机代码。以下是一个简单的示例：

using System;
using System.Net;
using System.Net.WebSockets;
using System.Threading;
using System.Threading.Tasks;

public class WebSocketHost
{
    public async Task Run(string listenerPrefix)
    {
        HttpListener listener = new HttpListener();
        listener.Prefixes.Add(listenerPrefix);
        listener.Start();

        Console.WriteLine("WebSocket server started.");

        while (true)
        {
            HttpListenerContext context = await listener.GetContextAsync();
            if (context.Request.IsWebSocketRequest)
            {
                ProcessWebSocketRequest(context);
            }
        }
    }

    private async void ProcessWebSocketRequest(HttpListenerContext context)
    {
        WebSocketContext webSocketContext = null;
        try
        {
            webSocketContext = await context.AcceptWebSocketAsync(subProtocol: null);
            Console.WriteLine("WebSocket connection established.");
            await ProcessWebSocketMessages(webSocketContext.WebSocket);
        }
        catch (Exception ex)
        {
            Console.WriteLine($"WebSocket error: {ex.Message}");
        }
        finally
        {
            if (webSocketContext != null)
            {
                webSocketContext.WebSocket.Dispose();
            }
        }
    }

    private async Task ProcessWebSocketMessages(WebSocket webSocket)
    {
        byte[] buffer = new byte[1024];
        while (webSocket.State == WebSocketState.Open)
        {
            WebSocketReceiveResult result = await webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);
            if (result.MessageType == WebSocketMessageType.Text)
            {
                string message = System.Text.Encoding.UTF8.GetString(buffer, 0, result.Count);
                Console.WriteLine($"Received message: {message}");

                byte[] responseBuffer = System.Text.Encoding.UTF8.GetBytes($"Response to {message}");
                await webSocket.SendAsync(new ArraySegment<byte>(responseBuffer, 0, responseBuffer.Length), WebSocketMessageType.Text, true, CancellationToken.None);
            }
            else if (result.MessageType == WebSocketMessageType.Close)
            {
                Console.WriteLine("WebSocket connection closed.");
                break;
            }
        }
    }
}

这个示例中，我们使用了 HttpListener 类来监听 WebSocket 请求，当请求到达时，通过调用 AcceptWebSocketAsync() 方法来接受 WebSocket 连接。一旦连接建立，我们就可以在 ProcessWebSocketMessages() 方法中实现 WebSocket 消息的接收和发送了。

需要注意的是，以上代码只是一个简单的示例，实际应用中需要考虑更多的异常处理和安全性等问题。