C# HTML5 Websocket 服务器

Question

我正在尝试创建一个 C# Websocket 服务器，但我似乎没有让它工作。 I now have a server that accepts the TCPClient, receives the HTTP request from the client and that tries to send back a HTTP response so the HTML5 WebSocket handshake can be completed.

我相信服务器发送给客户端的握手有问题。 我阅读了草案（Websocket 76 草案），其中指出在握手结束时必须对给出的两个键给出响应。 此响应由服务器计算。

这是我的代码：

static void Main(string[] args)
    {
        int port = 8181;
        IPAddress localAddr = IPAddress.Loopback;

        TcpListener server = new TcpListener(localAddr, port);
        server.Start();

        // Buffer for reading data
        Byte[] receivedBytes = new Byte[256];
        String data = null;

        // Enter the listening loop.
        while (true)
        {
            Console.WriteLine("Waiting for a connection...");

            // Perform a blocking call to accept requests.
            // You could also user server.AcceptSocket() here.
            TcpClient client = server.AcceptTcpClient();
            Console.WriteLine("Connected!\n");

            data = null;

            // Get a stream object for reading and writing
            NetworkStream stream = client.GetStream();

            int i;


            // Loop to receive all the data sent by the client.
            while ((i = stream.Read(receivedBytes, 0, receivedBytes.Length)) != 0)
            {
                // Translate data bytes to a ASCII string.
                data = System.Text.Encoding.UTF8.GetString(receivedBytes, 0, i);

                Console.WriteLine("Received:");
                Console.WriteLine(data);
                Byte[] response_token = hashResponse(data);


                string handshake = "HTTP/1.1 101 WebSocket Protocol Handshake\r\n"
                    + "Upgrade: WebSocket\r\n" + "Connection: Upgrade\r\n"
                    + "Sec-WebSocket-Origin: http://localhost\r\n"
                    + "Sec-WebSocket-Location: ws://localhost:8181/websession\r\n"
                    + "\r\n";

                Byte[] writtenBytes = Encoding.UTF8.GetBytes(handshake);

                stream.Write(writtenBytes, 0, writtenBytes.Length);
                stream.Write(response_token, 0, response_token.Length);

                Console.WriteLine("Send:");
                Console.WriteLine(handshake);

                string strHash = Encoding.UTF8.GetString(response_token);
                Console.WriteLine(strHash);
            }                
        }
    }

    static Byte[] hashResponse(string receivedData)
    {
        string strDel = "\r\n";
        char[] delimeter = strDel.ToCharArray();

        string Key1 = null;
        string Key2 = null;
        string hash = null;
        MD5 md5 = MD5.Create();

        string[] lines = receivedData.Split(delimeter);
        Key1 = lines[10].Substring(20);
        Key2 = lines[12].Substring(20);
        hash = lines[16];

        Int64 numbersKey1 = Convert.ToInt64(string.Join(null, Regex.Split(Key1, "[^\\d]")));
        Int64 numbersKey2 = Convert.ToInt64(string.Join(null, Regex.Split(Key2, "[^\\d]")));

        Int64 numberSpaces1 = countSpaces(Key1);
        Int64 numberSpaces2 = countSpaces(Key2);

        int dividedKey1 = (int) (numbersKey1 / numberSpaces1);
        int dividedKey2 = (int) (numbersKey2 / numberSpaces2);

        Byte[] encodedKey1 = Encoding.UTF8.GetBytes(dividedKey1.ToString());
        Byte[] encodedKey2 = Encoding.UTF8.GetBytes(dividedKey2.ToString());
        Byte[] encodedHash = Encoding.UTF8.GetBytes(hash);

        Byte[] combined = Encoding.UTF8.GetBytes(dividedKey1.ToString() + dividedKey2.ToString() + hash);

        Byte[] responseHash = md5.ComputeHash(combined); 
        return responseHash;
    }

    static int countSpaces(string key)
    {
        int counter = 0;
        char[] charArray = key.ToCharArray();

        foreach (char c in charArray)
        {
            if (c.Equals(' '))
                counter++;
        }

        return counter;
    }

The HTML page (which is named Test.html) I'm using for testing is hosted by an apache webserver which runs on my computer I access it by browsing (in Chrome) to http://localhost/Test.html

有没有人知道我做错了什么，因为我变得非常绝望。

提前致谢

丹尼斯

Answer 1

这是我根据draft-ietf-hybi-thewebsocketprotocol-00编写的示例服务器，说明了握手阶段：

using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Security.Cryptography;
using System.Text;
using System.Text.RegularExpressions;

class Program
{
    static void Main(string[] args)
    {
        var listener = new TcpListener(IPAddress.Loopback, 8080);
        listener.Start();
        while (true)
        {
            using (var client = listener.AcceptTcpClient())
            using (var stream = client.GetStream())
            {
                var headers = new Dictionary<string, string>();
                string line = string.Empty;
                while ((line = ReadLine(stream)) != string.Empty)
                {
                    var tokens = line.Split(new char[] { ':' }, 2);
                    if (!string.IsNullOrWhiteSpace(line) && tokens.Length > 1)
                    {
                        headers[tokens[0]] = tokens[1].Trim();
                    }
                }

                var key = new byte[8];
                stream.Read(key, 0, key.Length);

                var key1 = headers["Sec-WebSocket-Key1"];
                var key2 = headers["Sec-WebSocket-Key2"];

                var numbersKey1 = Convert.ToInt64(string.Join(null, Regex.Split(key1, "[^\\d]")));
                var numbersKey2 = Convert.ToInt64(string.Join(null, Regex.Split(key2, "[^\\d]")));
                var numberSpaces1 = CountSpaces(key1);
                var numberSpaces2 = CountSpaces(key2);

                var part1 = (int)(numbersKey1 / numberSpaces1);
                var part2 = (int)(numbersKey2 / numberSpaces2);

                var result = new List<byte>();
                result.AddRange(GetBigEndianBytes(part1));
                result.AddRange(GetBigEndianBytes(part2));
                result.AddRange(key);

                var response =
                    "HTTP/1.1 101 WebSocket Protocol Handshake" + Environment.NewLine +
                    "Upgrade: WebSocket" + Environment.NewLine +
                    "Connection: Upgrade" + Environment.NewLine +
                    "Sec-WebSocket-Origin: " + headers["Origin"] + Environment.NewLine +
                    "Sec-WebSocket-Location: ws://localhost:8080/websession" + Environment.NewLine + 
                    Environment.NewLine;

                var bufferedResponse = Encoding.UTF8.GetBytes(response);
                stream.Write(bufferedResponse, 0, bufferedResponse.Length);
                using (var md5 = MD5.Create())
                {
                    var handshake = md5.ComputeHash(result.ToArray());
                    stream.Write(handshake, 0, handshake.Length);
                }
            }
        }
    }

    static int CountSpaces(string key)
    {
        return key.Length - key.Replace(" ", string.Empty).Length;
    }

    static string ReadLine(Stream stream)
    {
        var sb = new StringBuilder();
        var buffer = new List<byte>();
        while (true)
        {
            buffer.Add((byte)stream.ReadByte());
            var line = Encoding.ASCII.GetString(buffer.ToArray());
            if (line.EndsWith(Environment.NewLine))
            {
                return line.Substring(0, line.Length - 2);
            }
        }
    }

    static byte[] GetBigEndianBytes(int value)
    {
        var bytes = 4;
        var buffer = new byte[bytes];
        int num = bytes - 1;
        for (int i = 0; i < bytes; i++)
        {
            buffer[num - i] = (byte)(value & 0xffL);
            value = value >> 8;
        }
        return buffer;
    }
}

和一个示例客户端：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <script type="text/javascript">
        var socket = new WebSocket('ws://localhost:8080/websession');
        socket.onopen = function() {
            alert('handshake successfully established. May send data now...');
        };
        socket.onclose = function() {
            alert('connection closed');
        };
    </script>
</head>
<body>
</body>
</html>

Answer 2

不知道能不能编译Objective C，不过这个项目真的很酷...

Blackbox is an embeddable Cocoa HTTP server -- that allows you to associate HTTP resources with Cocoa "responder" objects (kind of like Twisted Web does for Python) rather than files on your filesystem.

使用 Blackbox，您可以快速创建个人文件共享器，编写通过 HTTP 相互通信的应用程序，并为无头应用程序轻松创建 web 控制接口。

它基本上是一个漂亮的 package 中的Comet 服务器。 我希望我能多说一些，但我仍然想自己弄清楚 sockets ......

Answer 3

这是非常简单的 Websocket 回显服务器，我使用普通的 Sockets 实现了它。

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Text.RegularExpressions;
using System.Security.Cryptography;

namespace SimpleWebsocketServer {
    class Program {
        static void Main(string[] args) {
            var listeningSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            listeningSocket.Bind(new IPEndPoint(IPAddress.Any, port: 80));
            listeningSocket.Listen(0);

            while (true) {
                var clientSocket = listeningSocket.Accept();

                Console.WriteLine("A client connected.");

                var receivedData = new byte[1000000];
                var receivedDataLength = clientSocket.Receive(receivedData);

                var requestString = Encoding.UTF8.GetString(receivedData, 0, receivedDataLength);

                if (new Regex("^GET").IsMatch(requestString)) {
                    const string eol = "\r\n";

                    var receivedWebSocketKey = new Regex("Sec-WebSocket-Key: (.*)").Match(requestString).Groups[1].Value.Trim();
                    var keyHash = SHA1.Create().ComputeHash(Encoding.UTF8.GetBytes(receivedWebSocketKey + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"));

                    var response = "HTTP/1.1 101 Switching Protocols" + eol;
                    response += "Connection: Upgrade" + eol;
                    response += "Upgrade: websocket" + eol;
                    response += "Sec-WebSocket-Accept: " + Convert.ToBase64String(keyHash) + eol;
                    response += eol;

                    var responseBytes = Encoding.UTF8.GetBytes(response);

                    clientSocket.Send(responseBytes);
                }

                while (true) {
                    receivedData = new byte[1000000];
                    clientSocket.Receive(receivedData);

                    if ((receivedData[0] & (byte)Opcode.CloseConnection) == (byte)Opcode.CloseConnection) {
                        // Close connection request.
                        Console.WriteLine("Client disconnected.");
                        clientSocket.Close();
                        break;
                    } else {
                        var receivedPayload = ParsePayloadFromFrame(receivedData);
                        var receivedString = Encoding.UTF8.GetString(receivedPayload);

                        Console.WriteLine($"Client: {receivedString}");

                        var response = $"ECHO: {receivedString}";
                        var dataToSend = CreateFrameFromString(response);

                        Console.WriteLine($"Server: {response}");

                        clientSocket.Send(dataToSend);
                    }
                }
            }
        }

        public static byte[] ParsePayloadFromFrame(byte[] incomingFrameBytes) {
            var payloadLength = 0L;
            var totalLength = 0L;
            var keyStartIndex = 0L;

            // 125 or less.
            // When it's below 126, second byte is the payload length.
            if ((incomingFrameBytes[1] & 0x7F) < 126) {
                payloadLength = incomingFrameBytes[1] & 0x7F;
                keyStartIndex = 2;
                totalLength = payloadLength + 6;
            }

            // 126-65535.
            // When it's 126, the payload length is in the following two bytes
            if ((incomingFrameBytes[1] & 0x7F) == 126) {
                payloadLength = BitConverter.ToInt16(new[] { incomingFrameBytes[3], incomingFrameBytes[2] }, 0);
                keyStartIndex = 4;
                totalLength = payloadLength + 8;
            }

            // 65536 +
            // When it's 127, the payload length is in the following 8 bytes.
            if ((incomingFrameBytes[1] & 0x7F) == 127) {
                payloadLength = BitConverter.ToInt64(new[] { incomingFrameBytes[9], incomingFrameBytes[8], incomingFrameBytes[7], incomingFrameBytes[6], incomingFrameBytes[5], incomingFrameBytes[4], incomingFrameBytes[3], incomingFrameBytes[2] }, 0);
                keyStartIndex = 10;
                totalLength = payloadLength + 14;
            }

            if (totalLength > incomingFrameBytes.Length) {
                throw new Exception("The buffer length is smaller than the data length.");
            }

            var payloadStartIndex = keyStartIndex + 4;

            byte[] key = { incomingFrameBytes[keyStartIndex], incomingFrameBytes[keyStartIndex + 1], incomingFrameBytes[keyStartIndex + 2], incomingFrameBytes[keyStartIndex + 3] };

            var payload = new byte[payloadLength];
            Array.Copy(incomingFrameBytes, payloadStartIndex, payload, 0, payloadLength);
            for (int i = 0; i < payload.Length; i++) {
                payload[i] = (byte)(payload[i] ^ key[i % 4]);
            }

            return payload;
        }

        public enum Opcode {
            Fragment = 0,
            Text = 1,
            Binary = 2,
            CloseConnection = 8,
            Ping = 9,
            Pong = 10
        }

        public static byte[] CreateFrameFromString(string message, Opcode opcode = Opcode.Text) {
            var payload = Encoding.UTF8.GetBytes(message);

            byte[] frame;

            if (payload.Length < 126) {
                frame = new byte[1 /*op code*/ + 1 /*payload length*/ + payload.Length /*payload bytes*/];
                frame[1] = (byte)payload.Length;
                Array.Copy(payload, 0, frame, 2, payload.Length);
            } else if (payload.Length >= 126 && payload.Length <= 65535) {
                frame = new byte[1 /*op code*/ + 1 /*payload length option*/ + 2 /*payload length*/ + payload.Length /*payload bytes*/];
                frame[1] = 126;
                frame[2] = (byte)((payload.Length >> 8) & 255);
                frame[3] = (byte)(payload.Length & 255);
                Array.Copy(payload, 0, frame, 4, payload.Length);
            } else {
                frame = new byte[1 /*op code*/ + 1 /*payload length option*/ + 8 /*payload length*/ + payload.Length /*payload bytes*/];
                frame[1] = 127; // <-- Indicates that payload length is in following 8 bytes.
                frame[2] = (byte)((payload.Length >> 56) & 255);
                frame[3] = (byte)((payload.Length >> 48) & 255);
                frame[4] = (byte)((payload.Length >> 40) & 255);
                frame[5] = (byte)((payload.Length >> 32) & 255);
                frame[6] = (byte)((payload.Length >> 24) & 255);
                frame[7] = (byte)((payload.Length >> 16) & 255);
                frame[8] = (byte)((payload.Length >> 8) & 255);
                frame[9] = (byte)(payload.Length & 255);
                Array.Copy(payload, 0, frame, 10, payload.Length);
            }

            frame[0] = (byte)((byte)opcode | 0x80 /*FIN bit*/);

            return frame;
        }
    }
}

Answer 4

在尝试在套接字上接收数据之前尝试发送握手数据

这是一个可能对您有所帮助的示例

网袜样本