无法解码来自 Websocket 的消息

Question

我正在尝试将我的 HTML/JS 客户端连接到我的 C# 服务器作为大学项目的一部分，以允许用户实时通知。 （我只需要服务器能够在任何给定时间向特定用户发送消息）

我的服务器只是一个模拟，以便在我的项目中实现它。

我成功通过了握手阶段，我正在尝试从服务器向客户端发送一个纯字符串。我读过一些关于编码消息的方法，客户端不会给出“一个或多个保留位打开：reserved1 = 0，reserved2 = 1，reserved3 = 1”错误但没有成功。

如何通过 Socket 发送原始数据并在客户端对其进行解码？

我的服务器代码：

while (true)
{
    TcpListener sck = new TcpListener(IPAddress.Any, 7878);
    sck.Start(1000);
    TcpClient client = sck.AcceptTcpClient();

    NetworkStream _stream = client.GetStream();
    StreamReader clientStreamReader = new StreamReader(_stream);
    StreamWriter clientStreamWriter = new StreamWriter(_stream);
    while (true)
    {
        while (!_stream.DataAvailable) ;
        Byte[] bytes = new Byte[client.Available];
        _stream.Read(bytes, 0, bytes.Count());
        String data = Encoding.UTF8.GetString(bytes);

        if (Regex.IsMatch(data, "^GET"))
        {
            const string eol = "\r\n"; // HTTP/1.1 defines the sequence CR LF as the end-of-line marker

            Byte[] response = Encoding.UTF8.GetBytes("HTTP/1.1 101 Switching Protocols" + eol
                + "Connection: Upgrade" + eol
                + "Upgrade: websocket" + eol
                + "Sec-WebSocket-Accept: " + Convert.ToBase64String(
                    System.Security.Cryptography.SHA1.Create().ComputeHash(
                        Encoding.UTF8.GetBytes(
                            new System.Text.RegularExpressions.Regex("Sec-WebSocket-Key: (.*)").Match(data).Groups[1].Value.Trim() + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
                            )
                        )
                    ) + eol
                + eol);

            _stream.Write(response, 0, response.Length);
        }
        else
        {

        }
    }
}

我的客户代码：

<script type="text/javascript">
function WebSocketTest() {
    if ("WebSocket" in window) {
        alert("WebSocket is supported by your Browser!");

        // Let us open a web socket
        var ws = new WebSocket("ws://localhost:7878");

        ws.onopen = function () {

            // Web Socket is connected, send data using send()
            ws.send("Message to send");
            alert("Message is sent...");
        };

        ws.onmessage = function (evt) {
            var received_msg = evt.data;
            alert("Message is received...");
        };

        ws.onclose = function () {

            // websocket is closed.
            alert("Connection is closed...");
        };
    } else {

         // The browser doesn't support WebSocket
         alert("WebSocket NOT supported by your Browser!");
     }
 }
 </script>

Answer 1

我保留了我的服务器，但添加了一个发送字符串函数和一个解码消息函数：

public static string DecodeMessage(Byte[] bytes)
    {
        string incomingData = string.Empty;
        byte secondByte = bytes[1];
        int dataLength = secondByte & 127;
        int indexFirstMask = 2;
        if (dataLength == 126)
            indexFirstMask = 4;
        else if (dataLength == 127)
            indexFirstMask = 10;

        IEnumerable<byte> keys = bytes.Skip(indexFirstMask).Take(4);
        int indexFirstDataByte = indexFirstMask + 4;

        byte[] decoded = new byte[bytes.Length - indexFirstDataByte];
        for (int i = indexFirstDataByte, j = 0; i < bytes.Length; i++, j++)
        {
            decoded[j] = (byte)(bytes[i] ^ keys.ElementAt(j % 4));
        }

        return Encoding.UTF8.GetString(decoded, 0, decoded.Length);
    }

public static void SendString(string userName ,string str)
    {
        if (!userConnections.ContainsKey(userName))
            return;
        TcpClient client = userConnections[userName];
        NetworkStream _stream = client.GetStream();

        try
        {

            var buf = Encoding.UTF8.GetBytes(str);
            int frameSize = 64;

            var parts = buf.Select((b, i) => new { b, i })
                            .GroupBy(x => x.i / (frameSize - 1))
                            .Select(x => x.Select(y => y.b).ToArray())
                            .ToList();

            for (int i = 0; i < parts.Count; i++)
            {
                byte cmd = 0;
                if (i == 0) cmd |= 1;
                if (i == parts.Count - 1) cmd |= 0x80;

                _stream.WriteByte(cmd);
                _stream.WriteByte((byte)parts[i].Length);
                _stream.Write(parts[i], 0, parts[i].Length);
            }

            _stream.Flush();
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error");
        }


    }

其中 userConnections 是： public static Dictionary userConnections = new Dictionary(); 为了维护用户-连接关系

Answer 2

你可以使用SuperWebSocket，这个库会自动发送握手。

服务器：

using SuperSocket.SocketBase;
using SuperWebSocket;
using System;
using System.Net;
using System.Net.Sockets;

namespace Jees.Library.WebSocket
{
    public class WebSocket
    {
        WebSocketServer appServer;

        public event EventHandler ServerStarted;
        public event EventHandler ServerStopped;
        public event EventHandler MessageReceived;

        public string IP { get; } = string.Empty;
        public int Port { get; } = 1337; //change this to the port you want to use

        public WebSocket() => this.IP = GetLocalIPAddress(); //or set it manually

        public void Start()
        {
            appServer = new WebSocketServer();
            if (!appServer.Setup(this.IP, this.Port))
            {
                this.OnServerStarted(new WebSocketServerEventArgs(false));
                return;
            }
            /* start listening */
            appServer.NewMessageReceived += new SessionHandler<WebSocketSession, string>(AppServer_NewMessageReceived);
            if (appServer.Start())
                this.OnServerStarted(new WebSocketServerEventArgs(true));
            else
            {
                this.OnServerStarted(new WebSocketServerEventArgs(false));
                appServer = null;
                appServer.Dispose();
            }
        }

        public void Stop()
        {
            if (appServer != null)
            {
                appServer.Stop();
                this.OnServerStopped(new EventArgs());
                appServer = null;
                appServer.Dispose();
            }
        }

        private void AppServer_NewMessageReceived(WebSocketSession session, string message)
        {
            this.OnMessageReceived(new MessageReceivedEventArgs(message, session));
        }

        protected virtual void OnMessageReceived(EventArgs e) => this.MessageReceived?.Invoke(this, e);

        protected virtual void OnServerStarted(EventArgs e) => this.ServerStarted?.Invoke(this, e);

        protected virtual void OnServerStopped(EventArgs e) => this.ServerStopped?.Invoke(this, e);

        private string GetLocalIPAddress()
        {
            var host = Dns.GetHostEntry(Dns.GetHostName());
            foreach (var ip in host.AddressList)
                if (ip.AddressFamily == AddressFamily.InterNetwork)
                    return ip.ToString();
            throw new Exception("No network adapters with an IPv4 address in the system!");
        }
    }

    public class WebSocketServerEventArgs : EventArgs
    {
        public WebSocketServerEventArgs(bool success) => this.Success = success;
        public bool Success { get; }
    }

    public class MessageReceivedEventArgs : EventArgs
    {
        public MessageReceivedEventArgs(string message, WebSocketSession session)
        {
            this.Message = message;
            this.Session = session;
        }
        public string Message { get; }
        public WebSocketSession Session { get; }
    }
}

服务器设置（我使用UserControl）：

using DevExpress.XtraEditors;
using SuperWebSocket;
using System;
using System.Linq;
using System.Windows.Forms;

namespace WebSocketServer
{
    public partial class Server : UserControl
    {
        WebSocket server;
        WebSocketSession session;

        public Server()
        {
            InitializeComponent();

            server = new WebSocket();
            server.ServerStarted += Server_ServerStarted;
            server.ServerStopped += Server_ServerStopped;
            server.MessageReceived += Server_MessageReceived;
        }

        private void Server_MessageReceived(object sender, EventArgs e)
        {
            MessageReceivedEventArgs eventArgs = (MessageReceivedEventArgs)e;
            /* save session */
            this.session = eventArgs.Session;
            this.Log("SessionID: " + session.RemoteEndPoint.ToString() + "; Message: " + eventArgs.Message);
            /* send back the message to the client */
            this.session.Send(eventArgs.Message); //comment out if needed
        }

        private void Server_ServerStopped(object sender, EventArgs e)
        {
            this.Log("Server stopped!");
        }

        private void Server_ServerStarted(object sender, EventArgs e)
        {
            if ((e as WebSocketServerEventArgs).Success)
            {
                this.Log("Server started on ws://" + server.IP + ":" + server.Port + "/");
            }
            else
                this.Log("Can't start the server!");
        }

        private void Log(string message)
        {
            /* here, this.log is a TextBox */
            if (this.log.InvokeRequired)
                this.log.Invoke((MethodInvoker)delegate
                {
                    this.log.Text += DateTime.Now.ToString("yyyy/MM/dd HH:mm:ss") + " > " + message + Environment.NewLine;
                });
            else
            {
                this.log.Text += DateTime.Now.ToString("yyyy/MM/dd HH:mm:ss") + " > " + message + Environment.NewLine;
            }
        }

        /* a button to start the server */
        private void BtnStart_Click(object sender, EventArgs e) => server.Start();

        /* a button to stop the server */
        private void BtnStop_Click(object sender, EventArgs e) => server.Stop();

        /* a button to send a message from a TextBox to the client */
        private void BtnSend_Click(object sender, EventArgs e)
        {
            if (this.txtMessage.Text != string.Empty)
                this.SendMessage(this.txtMessage.Text);
        }

        private void SendMessage(string message)
        {
            try
            {
                /* use current session to send the message */
                this.session.Send(message);
                this.Log("Message: " + message + " sent to client!");
            }
            catch (Exception e)
            {
                this.Log(e.Message);
            }
        }
    }
}

如果您需要更多说明，请添加评论，我会更新我的答案！