如何处理关闭握手 C#

Question

我使用 websockets 和 https 调用在 c# 中开发了一个猜谜游戏。每次用户创建要玩的控制台应用程序实例时，它都会与服务器连接。 (等待 webSocket.ConnectAsync(new Uri("ws://localhost:xxx"), CancellationToken.None);).

我有一个 websocketmiddlewear class 来接受 websocket 请求和一个管理器 class 来处理 websockets 请求。一切正常，除非用户退出主机游戏。例如，当我在控制台 (cmd) 中按“x”时，出现以下错误

The remote party closed the WebSocket connection without completing the close handshake.

下一行

WebSocketReceiveResult result = await socket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);

为什么代码没有处理错误，我该如何解决？

ConnectionManagerService.cs

 public async Task Receive(WebSocket socket)
        {
            var buffer = new byte[1024 * 4];

            while (socket.State == WebSocketState.Open)
            {
                WebSocketReceiveResult result = await socket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);


               if (result.MessageType == WebSocketMessageType.Text)
                {
                    Console.WriteLine($"Receive->Text");      
                    return;   
                }
                else if (result.MessageType == WebSocketMessageType.Close)
                {
                    string id = _sockets.FirstOrDefault(s => s.Value == socket).Key;
                    //Console.WriteLine($"Receive->Close on: " + id);

                    _sockets.TryRemove(id, out socket);
                    Console.WriteLine("Managed Connections: " + _sockets.Count.ToString());

                    await socket.CloseOutputAsync(result.CloseStatus.Value, result.CloseStatusDescription, CancellationToken.None);
                    return;
                }
            }
        }
 

WebsocketMiddleware.cs

        }
        public async Task Invoke(HttpContext context)
        {
            var isSocketRequest = context.WebSockets.IsWebSocketRequest;
            if (isSocketRequest)
            {
                WebSocket socket = await context.WebSockets.AcceptWebSocketAsync();   
                _manager.AddSocket(socket);    
                await _manager.Receive(socket);

            }
            else
            {
                await _next(context);
            }
        }

Answer 1

发生这种情况是因为您只处理正常连接 disconnect.The 客户端可能会断开连接，并且您会在 read/write 操作过程中变大 ol SocketIO Exception .

考虑将您的 Socket 操作包装在 try-catch 中，并根据需要进行处理。

public async Task Receive(WebSocket socket)
        {
            var buffer = new byte[1024 * 4];
            try{
                while (true) 
                {
                    WebSocketReceiveResult result = await socket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);
                    if (result.MessageType == WebSocketMessageType.Text)
                    {
                        Console.WriteLine($"Receive->Text");      
                        return;   
                    }
                    else if (result.MessageType == WebSocketMessageType.Close)
                    {
                    string id = _sockets.FirstOrDefault(s => s.Value == socket).Key;
                    //Console.WriteLine($"Receive->Close on: " + id);

                    _sockets.TryRemove(id, out socket);
                    Console.WriteLine("Managed Connections: " + _sockets.Count.ToString());

                    await socket.CloseOutputAsync(result.CloseStatus.Value, result.CloseStatusDescription, CancellationToken.None);
                    return;
                    }
                } 
            } catch(Exception ex){   //not so graceful disconnect
                 _sockets.TryRemove(id, out socket);
                    //deal with closed connection 
                    //maybe reconnect ?
            }
        }

如何处理关闭握手 C#

How to handle the close handshake c#

c#

asp.net

websocket

handshake