javascript - 无法解码来自 Websocket 的消息

Question

作为大学项目的一部分，我正在尝试将我的 HTML/JS 客户端连接到我的 C# 服务器，以便允许用户实时通知。 (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。

我成功地通过了握手阶段，我正在尝试从服务器向客户端发送一个纯字符串。我阅读了一些关于对消息进行编码是客户端不会给出“一个或多个保留位打开:reserved1 = 0，reserved2 = 1，reserved3 = 1”错误但没有成功的方式。

如何通过套接字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

我保留了上面的服务器，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