Question

我有一个来自SO的另一个讨论的Websocket-Class，我根据自己的需要对其进行了调整。代码运行良好，直到第100行的serverSocket.BeginAccept(null, 0, OnAccept, null);，它结束整个程序，没有任何异常或错误。但我不知道为什么。有人提出建议吗？

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Security.Cryptography;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace WebSockets_Test
{
    class Program
    {
        static Socket serverSocket = new Socket(AddressFamily.InterNetwork,
        SocketType.Stream, ProtocolType.IP);
        static private string guid = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";

        static void Main(string[] args)
        {
            serverSocket.Bind(new IPEndPoint(IPAddress.Any, 8080));
            serverSocket.Listen(128);
            serverSocket.BeginAccept(null, 0, OnAccept, null);
            Console.Read();
        }

        private static void OnAccept(IAsyncResult result)
        {
            byte[] buffer = new byte[1024];
            try
            {
                Socket client = null;
                string headerResponse = "";
                if (serverSocket != null && serverSocket.IsBound)
                {
                    client = serverSocket.EndAccept(result);
                    var i = client.Receive(buffer);
                    headerResponse = (System.Text.Encoding.UTF8.GetString(buffer)).Substring(0, i);
                    // write received data to the console
                    Console.WriteLine(headerResponse);

                }
                if (client != null)
                {
                    /* Handshaking and managing ClientSocket */

                    var key = headerResponse.Replace("ey:", "`")
                              .Split('`')[1]                     // dGhlIHNhbXBsZSBub25jZQ== \r\n .......
                              .Replace("\r", "").Split('\n')[0]  // dGhlIHNhbXBsZSBub25jZQ==
                              .Trim();

                    // key should now equal dGhlIHNhbXBsZSBub25jZQ==
                    var test1 = AcceptKey(ref key);

                    var newLine = "\r\n";

                    var response = "HTTP/1.1 101 Switching Protocols" + newLine
                         + "Upgrade: websocket" + newLine
                         + "Connection: Upgrade" + newLine
                         + "Sec-WebSocket-Accept: " + test1 + newLine + newLine
                        //+ "Sec-WebSocket-Protocol: chat, superchat" + newLine
                        //+ "Sec-WebSocket-Version: 13" + newLine
                         ;

                    // which one should I use? none of them fires the onopen method
                    client.Send(System.Text.Encoding.UTF8.GetBytes(response));

                    var i = client.Receive(buffer); // wait for client to send a message

                    // once the message is received decode it in different formats
                    Console.WriteLine(Convert.ToBase64String(buffer).Substring(0, i));


                    try
                    {
                        if (serverSocket != null && serverSocket.IsBound)
                        {
                            var Respone = EncodeMessageToSend("Test");
                            client.Send(Respone);
                        }
                    }
                    catch (Exception ex)
                    {
                        Console.Write(ex);
                    }
                    Thread.Sleep(5000);//wait for message to be send

                }
            }
            catch (SocketException exception)
            {
                throw exception;
            }
            finally
            {
                if (serverSocket != null && serverSocket.IsBound)
                {
                    try
                    {
                        serverSocket.BeginAccept(null, 0, OnAccept, null); //here ist the crash!!!!!
                    }
                    catch (SocketException exception)
                    {
                        throw exception;
                    }
                }
            }
        }

        private static Byte[] EncodeMessageToSend(String message)
        {
            Byte[] response;
            Byte[] bytesRaw = Encoding.UTF8.GetBytes(message);
            Byte[] frame = new Byte[10];

            Int32 indexStartRawData = -1;
            Int32 length = bytesRaw.Length;

            frame[0] = (Byte)129;
            if (length <= 125)
            {
                frame[1] = (Byte)length;
                indexStartRawData = 2;
            }
            else if (length >= 126 && length <= 65535)
            {
                frame[1] = (Byte)126;
                frame[2] = (Byte)((length >> 8) & 255);
                frame[3] = (Byte)(length & 255);
                indexStartRawData = 4;
            }
            else
            {
                frame[1] = (Byte)127;
                frame[2] = (Byte)((length >> 56) & 255);
                frame[3] = (Byte)((length >> 48) & 255);
                frame[4] = (Byte)((length >> 40) & 255);
                frame[5] = (Byte)((length >> 32) & 255);
                frame[6] = (Byte)((length >> 24) & 255);
                frame[7] = (Byte)((length >> 16) & 255);
                frame[8] = (Byte)((length >> 8) & 255);
                frame[9] = (Byte)(length & 255);

                indexStartRawData = 10;
            }

            response = new Byte[indexStartRawData + length];

            Int32 i, reponseIdx = 0;

            //Add the frame bytes to the reponse
            for (i = 0; i < indexStartRawData; i++)
            {
                response[reponseIdx] = frame[i];
                reponseIdx++;
            }

            //Add the data bytes to the response
            for (i = 0; i < length; i++)
            {
                response[reponseIdx] = bytesRaw[i];
                reponseIdx++;
            }

            return response;
        }

        private static string AcceptKey(ref string key)
        {
            string longKey = key + guid;
            byte[] hashBytes = ComputeHash(longKey);
            return Convert.ToBase64String(hashBytes);
        }

        static SHA1 sha1 = SHA1CryptoServiceProvider.Create();
        private static byte[] ComputeHash(string str)
        {
            return sha1.ComputeHash(System.Text.Encoding.ASCII.GetBytes(str));
        }
    }
}

Answer 1

如果不抛出异常或记录任何内容，它就不可能结束。可能是在后台吞下了一个异常（例如在异步OnAccept回调中），但仍导致整个程序失败。确保你写出你在该行上捕获的异常而不是仅仅重新抛出它：

try
{
    serverSocket.BeginAccept(null, 0, OnAccept, null); //here ist the crash!!!!!
}
catch (SocketException exception)
{
    Console.Write(exception.Message);
    throw;  //Note: "throw" is better than "throw exception" - it keeps
            //the stack trace intact.
}

另一种可能是你在窗口聚焦时无意中按下了一个键，导致Console.Read()在Main内完成，这也将结束该程序。

Websocket服务器在接受新连接时崩溃

1 个答案: