Socket 服務端收發WebSocket 消息解析與打包（附帶握手協議代碼）

接收WebSocket數據

主要接收代碼塊

        var result = JsonConvert.DeserializeObject<SocketModel>(AnalyticData(buffer, length));

解析數據方法（AnalyticData）

        /// <summary>
        /// 解析客戶端數據包
        /// </summary>
        /// <param name="recBytes">服務器接收的數據包</param>
        /// <param name="recByteLength">有效數據長度</param>
        /// <returns></returns>
        private static string AnalyticData(byte[] recBytes, int recByteLength)
        {
            if (recByteLength < 2) { return string.Empty; }

            bool fin = (recBytes[0] & 0x80) == 0x80; // 1bit，1表示最後一幀  
            if (!fin)
            {
                return string.Empty;// 超過一幀暫不處理 
            }

            bool mask_flag = (recBytes[1] & 0x80) == 0x80; // 是否包含掩碼  
            if (!mask_flag)
            {
                return string.Empty;// 不包含掩碼的暫不處理
            }

            int payload_len = recBytes[1] & 0x7F; // 數據長度  

            byte[] masks = new byte[4];
            byte[] payload_data;

            if (payload_len == 126)
            {
                Array.Copy(recBytes, 4, masks, 0, 4);
                payload_len = (UInt16)(recBytes[2] << 8 | recBytes[3]);
                payload_data = new byte[payload_len];
                Array.Copy(recBytes, 8, payload_data, 0, payload_len);

            }
            else if (payload_len == 127)
            {
                Array.Copy(recBytes, 10, masks, 0, 4);
                byte[] uInt64Bytes = new byte[8];
                for (int i = 0; i < 8; i++)
                {
                    uInt64Bytes[i] = recBytes[9 - i];
                }
                UInt64 len = BitConverter.ToUInt64(uInt64Bytes, 0);

                payload_data = new byte[len];
                for (UInt64 i = 0; i < len; i++)
                {
                    payload_data[i] = recBytes[i + 14];
                }
            }
            else
            {
                Array.Copy(recBytes, 2, masks, 0, 4);
                payload_data = new byte[payload_len];
                Array.Copy(recBytes, 6, payload_data, 0, payload_len);

            }

            for (var i = 0; i < payload_len; i++)
            {
                payload_data[i] = (byte)(payload_data[i] ^ masks[i % 4]);
            }

            return Encoding.UTF8.GetString(payload_data);
        }

發送消息到WebSocket

主要發送代碼塊：

        var jsonString = JsonConvert.SerializeObject(socketCall);
        _socket.Send(PackData(jsonString));

打包數據方法（PackData）

        /// <summary>
        /// 打包服務器數據
        /// </summary>
        /// <param name="message">數據</param>
        /// <returns>數據包</returns>
        private static byte[] PackData(string message)
        {
            byte[] contentBytes = null;
            byte[] temp = Encoding.UTF8.GetBytes(message);

            if (temp.Length < 126)
            {
                contentBytes = new byte[temp.Length + 2];
                contentBytes[0] = 0x81;
                contentBytes[1] = (byte)temp.Length;
                Array.Copy(temp, 0, contentBytes, 2, temp.Length);
            }
            else if (temp.Length < 0xFFFF)
            {
                contentBytes = new byte[temp.Length + 4];
                contentBytes[0] = 0x81;
                contentBytes[1] = 126;
                contentBytes[2] = (byte)(temp.Length & 0xFF);
                contentBytes[3] = (byte)(temp.Length >> 8 & 0xFF);
                Array.Copy(temp, 0, contentBytes, 4, temp.Length);
            }
            else
            {
                // 暫不處理超長內容  
            }

            return contentBytes;
        }

發送握手協議

        socketSend.Send(PackHandShakeData(GetSecKeyAccetp(buffer, length)));

        /// <summary>
        /// 打包握手信息
        /// </summary>
        /// <param name="secKeyAccept">Sec-WebSocket-Accept</param>
        /// <returns>數據包</returns>
        private static byte[] PackHandShakeData(string secKeyAccept)
        {
            var responseBuilder = new StringBuilder();
            responseBuilder.Append("HTTP/1.1 101 Switching Protocols" + Environment.NewLine);
            responseBuilder.Append("Upgrade: websocket" + Environment.NewLine);
            responseBuilder.Append("Connection: Upgrade" + Environment.NewLine);
            responseBuilder.Append("Sec-WebSocket-Accept: " + secKeyAccept + Environment.NewLine + Environment.NewLine);
            //如果把上一行換成下面兩行，纔是thewebsocketprotocol-17協議，但居然握手不成功，目前仍沒弄明白！
            //responseBuilder.Append("Sec-WebSocket-Accept: " + secKeyAccept + Environment.NewLine);
            //responseBuilder.Append("Sec-WebSocket-Protocol: chat" + Environment.NewLine);

            return Encoding.UTF8.GetBytes(responseBuilder.ToString());
        }

        /// <summary>
        /// 生成Sec-WebSocket-Accept
        /// </summary>
        /// <returns>Sec-WebSocket-Accept</returns>
        private static string GetSecKeyAccetp(byte[] handShakeBytes, int bytesLength)
        {
            string handShakeText = Encoding.UTF8.GetString(handShakeBytes, 0, bytesLength);
            string key = string.Empty;
            Regex r = new Regex(@"Sec\-WebSocket\-Key:(.*?)\r\n");
            Match m = r.Match(handShakeText);
            if (m.Groups.Count != 0)
            {
                key = Regex.Replace(m.Value, @"Sec\-WebSocket\-Key:(.*?)\r\n", "$1").Trim();
            }
            byte[] encryptionString = SHA1.Create().ComputeHash(Encoding.ASCII.GetBytes(key + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"));
            return Convert.ToBase64String(encryptionString);
        }

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