【问题标题】:Stopping an asynchronous TCP server on separate thread in C#在 C# 中的单独线程上停止异步 TCP 服务器
【发布时间】:2010-09-21 00:55:59
【问题描述】:

我已经实现了一个由另一个进程生成的异步 TCP 服务器。它可以正常启动并按预期运行,但是当我结束启动它的进程时,我无法终止服务器。

以下是我当前的 TCP 服务器和其他进程的停止功能。

TCP 服务器

    public class StateObject
    {
        //Client socket.
        public Socket workSocket = null;
        //Size of receive buffer.
        public const int BufferSize = 1024;
        //Receive buffer.
        public byte[] buffer = new byte[BufferSize];
        //Received data string.
        public StringBuilder sb = new StringBuilder();
    }

    public class AsynchronousSocketListener : Strategy
    {
        //Thread signal.
        public static ManualResetEvent allDone = new ManualResetEvent(false);
        public volatile bool listening = true;

        //User-specified port number.
        private int Port;

        public AsynchronousSocketListener(int port)
        {
            Port = port;
        }

        public void StopListening()
        {
            listening = false;
        }

        public void StartListening()
        {
            //Data buffer for incoming data.
            byte[] bytes = new Byte[1024];

            //Establish the local endpoint for the socket.
            IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
            IPAddress ipAddress = ipHostInfo.AddressList[0];
            IPEndPoint localEndPoint = new IPEndPoint(ipAddress, Port);

            //Create a TCP/IP socket.
            Socket listener = new Socket(AddressFamily.InterNetwork,
                SocketType.Stream, ProtocolType.Tcp);

            //Bind the socket to the local endpoint and listen for
            //incoming connections.
            try
            {
                listener.Bind(localEndPoint);
                listener.Listen(100);

                while (listening)
                {
                    //Set the event to nonsignaled state.
                    allDone.Reset();    

                    //Start an asychronous socket to listen for connections.
                    Print("Waiting for a connection...");
                    listener.BeginAccept(
                    new AsyncCallback(AcceptCallback),
                        listener);

                    //Wait until a connection is made before continuing.
                    allDone.WaitOne();
                }
            }
            catch (Exception e)
            {
                Print(e.ToString());    
            }
        }

        public void AcceptCallback(IAsyncResult arg)
        {
            //Signal the main thread to continue.
            allDone.Set();

            //Get the socket that handles the client request.
            Socket listener = (Socket) arg.AsyncState;
            Socket handler = listener.EndAccept(arg);

            //Create the state object.
            StateObject state = new StateObject();
            state.workSocket = handler;
            handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
                new AsyncCallback(ReadCallback), state);
        }

        public void ReadCallback(IAsyncResult arg)
        {
            String content = String.Empty;

            //Retrieve the state object and the handler socket
            //from the asynchronous state object.
            StateObject state = (StateObject) arg.AsyncState;
            Socket handler = state.workSocket;

            //Read data from the client socket.
            int bytesRead = handler.EndReceive(arg);

            if (bytesRead > 0)
            {
                //There might be more data, so store the data received so far.
                state.sb.Append(Encoding.ASCII.GetString(
                    state.buffer,0,bytesRead));

                //Check for end-of-file tag. If it is not there, read
                //more data.
                content = state.sb.ToString();
                if (content.IndexOf("<EOF>") > -1)
                {
                    //All the data has been read from the
                    //client. Display it on the console.
                    Print("Read " + content.Length + " bytes from socket. \n Data : " + content);
                    //Echo the data back to the client.
                    Send(handler, content);
                }
                else
                {
                    //Not all data received. Get more.
                    handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
                        new AsyncCallback(ReadCallback), state);
                }
            }
        }

        private void Send(Socket handler, String data)
        {
            //Convert the string data to byte data using ASCII encoding.
            byte[] byteData = Encoding.ASCII.GetBytes(data);

            //Begin sending the data to the remote device.
            handler.BeginSend(byteData,0,byteData.Length,0,
                new AsyncCallback(SendCallback),handler);
        }

        private void SendCallback(IAsyncResult arg)
        {
            try
            {
                //Retrieve the socket from the state object.
                Socket handler = (Socket) arg.AsyncState;

                //Complete sending the data to the remote device.
                int bytesSent = handler.EndSend(arg);
                Print("Sent " + bytesSent + " bytes to client.");

                handler.Shutdown(SocketShutdown.Both);
                handler.Close();
            }
            catch (Exception e)
            {
                Print(e.ToString());    
            }
        }
    }

产卵过程

//private NinjaTerminal.Server server;
        private NinjaTerminal.AsynchronousSocketListener    server;
        private Thread                                      listenThread;
        private int                                         _Port = 8080;

    protected override void OnStartUp() 
    {
        server = new NinjaTerminal.AsynchronousSocketListener(Port);
        listenThread = new Thread(new ThreadStart(server.StartListening));
        listenThread.Start();
    }

    protected override void OnTermination() 
    {
        listenThread.stopListening();
        listenThread.Join();
    }

现在我已经验证 OnTermination() 被调用,并且它确实加入了服务器线程,但是服务器线程永远不会结束。

我希望得到一些关于原因的见解,以及对更好架构的建议,或者更受欢迎。在这个阶段,除了设置 TCP 服务器,我还没有投入太多,所以如果你有不同/更好的想法,我很乐意听到。

另外,我已经通过 StackOverflow 搜索了高低的答案,但没有一个真正适用于异步 TCP 服务器。我正在使用 .NET 3.5

Reed 答案的代码补充

public void StopListening() { 听=假; allDone.Set(); }

    public void StartListening()
    {
        //Data buffer for incoming data.
        byte[] bytes = new Byte[1024];

        //Establish the local endpoint for the socket.
        IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
        IPAddress ipAddress = ipHostInfo.AddressList[0];
        IPEndPoint localEndPoint = new IPEndPoint(ipAddress, Port);

        //Create a TCP/IP socket.
        Socket listener = new Socket(AddressFamily.InterNetwork,
            SocketType.Stream, ProtocolType.Tcp);

        //Bind the socket to the local endpoint and listen for
        //incoming connections.
        try
        {
            listener.Bind(localEndPoint);
            listener.Listen(100);

            while (listening)
            {
                //Set the event to nonsignaled state.
                allDone.Reset();    

                //Start an asychronous socket to listen for connections.
                Print("Waiting for a connection...");
                listener.BeginAccept(
                new AsyncCallback(AcceptCallback),
                    listener);

                //Wait until a connection is made before continuing.
                allDone.WaitOne();
            }
            listener.Close();
        }
        catch (Exception e)
        {
            Print(e.ToString());    
        }
    }

【问题讨论】:

    标签: c# asynchronous tcp blocking


    【解决方案1】:

    您需要将StopListening 更改为还包括一个调用来向您的WaitHandle 发出信号:

    public void StopListening()
    {
        this.listening = false;
        this.allDone.Set();
    }
    

    没有这个,您的StartListening 例程将永远挂在这里:

    //Wait until a connection is made before continuing.
    allDone.WaitOne();
    

    【讨论】:

    • 啊,现在我已经尝试了您刚才在这里建议的变体,但我使用了 allDone.WaitOne();在我的 StopListening() 方法中而不是 allDone.Set();
    • 要添加到这个答案,因为它没有完全完成,在我设置监听为 false 并且 StartListening 例程可以重新开始并退出 while 循环后,我仍然需要关闭监听器。我已经用相关代码编辑了问题,因为评论不适合这类事情。
    • @Zach:我只是想告诉你为什么“服务器线程永远不会结束”;)
    • 嗯,你确实做到了,这是我的问题。感谢您的洞察力,我真的被困在那里了。
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