本章根据Socket异步聊天室修改成C# WebSocket聊天室

WebSocket特别的地方是 握手和消息内容的编码、解码（添加了ServerHelper协助处理）

ServerHelper：

using System;
using System.Collections;
using System.Text;
using System.Security.Cryptography;

namespace SocketDemo
{
    // Server助手 负责：1 握手 2 请求转换 3 响应转换
    class ServerHelper
    {
        /// <summary>
        /// 输出连接头信息
        /// </summary>
        public static string ResponseHeader(string requestHeader)
        {
            Hashtable table = new Hashtable();

            // 拆分成键值对，保存到哈希表
            string[] rows = requestHeader.Split(new string[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
            foreach (string row in rows)
            {
                int splitIndex = row.IndexOf(':');
                if (splitIndex > 0)
                {
                    table.Add(row.Substring(0, splitIndex).Trim(), row.Substring(splitIndex + 1).Trim());
                }
            }

            StringBuilder header = new StringBuilder();
            header.Append("HTTP/1.1 101 Web Socket Protocol Handshake\r\n");
            header.AppendFormat("Upgrade: {0}\r\n", table.ContainsKey("Upgrade") ? table["Upgrade"].ToString() : string.Empty);
            header.AppendFormat("Connection: {0}\r\n", table.ContainsKey("Connection") ? table["Connection"].ToString() : string.Empty);
            header.AppendFormat("WebSocket-Origin: {0}\r\n", table.ContainsKey("Sec-WebSocket-Origin") ? table["Sec-WebSocket-Origin"].ToString() : string.Empty);
            header.AppendFormat("WebSocket-Location: {0}\r\n", table.ContainsKey("Host") ? table["Host"].ToString() : string.Empty);

            string key = table.ContainsKey("Sec-WebSocket-Key") ? table["Sec-WebSocket-Key"].ToString() : string.Empty;
            string magic = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
            header.AppendFormat("Sec-WebSocket-Accept: {0}\r\n", Convert.ToBase64String(SHA1.Create().ComputeHash(Encoding.ASCII.GetBytes(key + magic))));

            header.Append("\r\n");

            return header.ToString();
        }

        /// <summary>
        /// 解码请求内容
        /// </summary>
        public static string DecodeMsg(Byte[] buffer, int len)
        {
            if (buffer[0] != 0x81
                || (buffer[0] &amp; 0x80) != 0x80
                || (buffer[1] &amp; 0x80) != 0x80)
            {
                return null;
            }
            Byte[] mask = new Byte[4];
            int beginIndex = 0;
            int payload_len = buffer[1] &amp; 0x7F;
            if (payload_len == 0x7E)
            {
                Array.Copy(buffer, 4, mask, 0, 4);
                payload_len = payload_len &amp; 0x00000000;
                payload_len = payload_len | buffer[2];
                payload_len = (payload_len << 8) | buffer[3];
                beginIndex = 8;
            }
            else if (payload_len != 0x7F)
            {
                Array.Copy(buffer, 2, mask, 0, 4);
                beginIndex = 6;
            }

            for (int i = 0; i < payload_len; i++)
            {
                buffer[i + beginIndex] = (byte)(buffer[i + beginIndex] ^ mask[i % 4]);
            }
            return Encoding.UTF8.GetString(buffer, beginIndex, payload_len);
        }

        /// <summary>
        /// 编码响应内容
        /// </summary>
        public static byte[] EncodeMsg(string content)
        {
            byte[] bts = null;
            byte[] temp = Encoding.UTF8.GetBytes(content);
            if (temp.Length < 126)
            {
                bts = new byte[temp.Length + 2];
                bts[0] = 0x81;
                bts[1] = (byte)temp.Length;
                Array.Copy(temp, 0, bts, 2, temp.Length);
            }
            else if (temp.Length < 0xFFFF)
            {
                bts = new byte[temp.Length + 4];
                bts[0] = 0x81;
                bts[1] = 126;
                bts[2] = (byte)(temp.Length &amp; 0xFF);
                bts[3] = (byte)(temp.Length >> 8 &amp; 0xFF);
                Array.Copy(temp, 0, bts, 4, temp.Length);
            }
            else
            {
                byte[] st = System.Text.Encoding.UTF8.GetBytes(string.Format("暂不处理超长内容").ToCharArray());
            }
            return bts;
        }
    }
}

Server：

using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.Net.Sockets;

namespace SocketDemo
{
    class ClientInfo
    {
        public Socket Socket { get; set; }
        public bool IsOpen { get; set; }
        public string Address { get; set; }
    }

    // 管理Client
    class ClientManager
    {
        static List<ClientInfo> clientList = new List<ClientInfo>();
        public static void Add(ClientInfo info)
        {
            if (!IsExist(info.Address))
            {
                clientList.Add(info);
            }
        }
        public static bool IsExist(string address)
        {
            return clientList.Exists(item => string.Compare(address, item.Address, true) == 0);
        }
        public static bool IsExist(string address, bool isOpen)
        {
            return clientList.Exists(item => string.Compare(address, item.Address, true) == 0 &amp;&amp; item.IsOpen == isOpen);
        }
        public static void Open(string address)
        {
            clientList.ForEach(item =>
            {
                if (string.Compare(address, item.Address, true) == 0)
                {
                    item.IsOpen = true;
                }
            });
        }
        public static void Close(string address = null)
        {
            clientList.ForEach(item =>
            {
                if (address == null || string.Compare(address, item.Address, true) == 0)
                {
                    item.IsOpen = false;
                    item.Socket.Shutdown(SocketShutdown.Both);
                }
            });
        }
        // 发送消息到ClientList
        public static void SendMsgToClientList(string msg, string address = null)
        {
            clientList.ForEach(item =>
            {
                if (item.IsOpen &amp;&amp; (address == null || item.Address != address))
                {
                    SendMsgToClient(item.Socket, msg);
                }
            });
        }
        public static void SendMsgToClient(Socket client, string msg)
        {
            byte[] bt = ServerHelper.EncodeMsg(msg);
            client.BeginSend(bt, 0, bt.Length, SocketFlags.None, new AsyncCallback(SendTarget), client);
        }
        private static void SendTarget(IAsyncResult res)
        {
            //Socket client = (Socket)res.AsyncState;
            //int size = client.EndSend(res);
        }
    }

    // 接收消息
    class ReceiveHelper
    {
        public byte[] Bytes { get; set; }
        public void ReceiveTarget(IAsyncResult res)
        {
            Socket client = (Socket)res.AsyncState;
            int size = client.EndReceive(res);
            if (size > 0)
            {
                string address = client.RemoteEndPoint.ToString(); // 获取Client的IP和端口
                string stringdata = null;
                if (ClientManager.IsExist(address, false)) // 握手
                {
                    stringdata = Encoding.UTF8.GetString(Bytes, 0, size);
                    ClientManager.SendMsgToClient(client, ServerHelper.ResponseHeader(stringdata));
                    ClientManager.Open(address);
                }
                else
                {
                    stringdata = ServerHelper.DecodeMsg(Bytes, size);
                }
                if (stringdata.IndexOf("exit") > -1)
                {
                    ClientManager.SendMsgToClientList(address + "已从服务器断开", address);
                    ClientManager.Close(address);
                    Console.WriteLine(address + "已从服务器断开");
                    Console.WriteLine(address + " " + DateTimeOffset.Now.ToString("G"));
                    return;
                }
                else
                {
                    Console.WriteLine(stringdata);
                    Console.WriteLine(address + " " + DateTimeOffset.Now.ToString("G"));
                    ClientManager.SendMsgToClientList(stringdata, address);
                }
            }
            // 继续等待
            client.BeginReceive(Bytes, 0, Bytes.Length, SocketFlags.None, new AsyncCallback(ReceiveTarget), client);
        }
    }

    // 监听请求
    class AcceptHelper
    {
        public byte[] Bytes { get; set; }

        public void AcceptTarget(IAsyncResult res)
        {
            Socket server = (Socket)res.AsyncState;
            Socket client = server.EndAccept(res);
            string address = client.RemoteEndPoint.ToString();

            ClientManager.Add(new ClientInfo() { Socket = client, Address = address, IsOpen = false });
            ReceiveHelper rs = new ReceiveHelper() { Bytes = this.Bytes };
            IAsyncResult recres = client.BeginReceive(rs.Bytes, 0, rs.Bytes.Length, SocketFlags.None, new AsyncCallback(rs.ReceiveTarget), client);
            // 继续监听
            server.BeginAccept(new AsyncCallback(AcceptTarget), server);
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            server.Bind(new IPEndPoint(IPAddress.Parse("127.0.0.1"), 200)); // 绑定IP+端口
            server.Listen(10); // 开始监听

            Console.WriteLine("等待连接...");

            AcceptHelper ca = new AcceptHelper() { Bytes = new byte[2048] };
            IAsyncResult res = server.BeginAccept(new AsyncCallback(ca.AcceptTarget), server);

            string str = string.Empty;
            while (str != "exit")
            {
                str = Console.ReadLine();
                Console.WriteLine("ME: " + DateTimeOffset.Now.ToString("G"));
                ClientManager.SendMsgToClientList(str);
            }
            ClientManager.Close();
            server.Close();
        }
    }
}

Client：

<!DOCTYPE html>
<script>
    var mySocket;
    function Star() {
        mySocket = new WebSocket("ws://127.0.0.1:200", "my-custom-protocol");
        mySocket.onopen = function Open() {
            Show("连接打开");
        };
        mySocket.onmessage = function (evt) {
            Show(evt.data);
        };
        mySocket.onclose = function Close() {
            Show("连接关闭");
            mySocket.close();
        };
    }
    function Send() {
        var content = document.getElementById("content").value;
        Show(content);
        mySocket.send(content);
    }
    function Show(msg) {
        var roomContent = document.getElementById("roomContent");
        roomContent.innerHTML = msg + "<br/>" + roomContent.innerHTML;
    }
</script>
<html>
<head>
    <title></title>
</head>
<body>
    <div id="roomContent" style="width: 500px; height: 200px; overflow: hidden; border: 2px solid #686868;
        margin-bottom: 10px; padding: 10px 0px 0px 10px;">
    </div>
    <div>
        <textarea id="content" cols="50" rows="3" style="padding: 10px 0px 0px 10px;"></textarea>
    </div>
    <input type="button" value="Connection" onclick="Star()" />
    <input type="button" value="Send" onclick="Send()" />
</body>
</html>