在使用Socket類的C＃Web表單應用程序中，如何發送兩個連續的消息？

Question

我是套接字的新手。 一位同事提供了一個用Python編寫的應用程序，該應用程序具有永遠運行的TCP套接字服務器。 該程序將交付給我們的客戶，並將與客戶將提供的客戶應用程序連接。 我已經用C＃編寫了一個測試WinFormas小應用程序，該應用程序應該執行客戶的客戶端應用程序所要做的事情。 我可以將一條消息從測試程序發送到服務器，然后服務器正確響應並發送回一個確認。 我現在正嘗試發送第二條消息，但出現一個異常：“已建立的連接已被您主機中的軟件中止”。 在它可以發送另一條消息之前，我需要做些什么來重置客戶端的套接字嗎？

客戶端的套接字最初是在以下循環中設置的：

    while (!connected)
    {
        try
        {
            if (m_sendSocket == null)
            {
                m_sendSocket = new Socket(AddressFamily.InterNetwork,
                                                SocketType.Stream, ProtocolType.Tcp);
            }
            m_sendSocket.Connect(sendRemoteEP);
            connected = true;
            btnMoveItem.Enabled = true;
            btnCloseSockets.Enabled = true;
            btnOpenSockets.Enabled = false;
        }
        catch (SocketException socketEx)
        {
            Thread.Sleep(5000);
        }
        catch (Exception ex)
        {
            MessageBox.Show("Failed to connect to sockets: " + ex.Message);
            break;
        }
    }

客戶端使用以下方法發送消息：

private void SendMessage(string message)
{
    // Data buffer for incoming data.
    byte[] bytes = new byte[1024];

    // Connect to a remote device.
    try {

        // Connect the socket to the remote endpoint. Catch any errors.
        try 
        {
            //Console.WriteLine("Socket connected to {0}",
            //    sender.RemoteEndPoint.ToString());

            // Encode the data string into a byte array.
            byte[] msg = Encoding.ASCII.GetBytes(message);

            // Send the data through the socket.
            int bytesSent = m_sendSocket.Send(msg);

            // Receive the response from the remote device.
            int bytesRec = m_sendSocket.Receive(bytes);
            int ackDelay = 0;
            while (bytesRec == 0)
            {
                Thread.Sleep(500);
                ackDelay += 500;
                if (ackDelay > 10000)
                {
                    using (StreamWriter writer = new StreamWriter("c:/misc/mes_simulator.log", true))
                    {
                        writer.WriteLine("No transport information acknowledgement received in ten seconds.");
                    }
                    break;
                }
                bytesRec = m_sendSocket.Receive(bytes);
            }

            MessageBox.Show("Acknowledgement message: " + Encoding.ASCII.GetString(bytes, 0, bytesRec));

            if (MessageBox.Show("Send duplicate message?", "Send another?", MessageBoxButtons.YesNo) == DialogResult.Yes)
            {
                // Send the data through the socket AGAIN to see if we can.
                bytesSent = m_sendSocket.Send(msg);

                // Receive the response from the remote device.
                bytesRec = m_sendSocket.Receive(bytes);
                ackDelay = 0;
                while (bytesRec == 0)
                {
                    Thread.Sleep(500);
                    ackDelay += 500;
                    if (ackDelay > 10000)
                    {
                        using (StreamWriter writer = new StreamWriter("c:/misc/mes_simulator.log", true))
                        {
                            writer.WriteLine("No transport information acknowledgement received in ten seconds.");
                        }
                        break;
                    }
                    bytesRec = m_sendSocket.Receive(bytes);
                }
            }

            //Console.WriteLine("Echoed test = {0}",
            //    Encoding.ASCII.GetString(bytes,0,bytesRec));

            // Release the socket.
            // sender.Shutdown(SocketShutdown.Send);
            // sender.Close();

        } 
        catch (ArgumentNullException ane) 
        {
            FormattedMessageBox.Show("ArgumentNullException : {0}", ane.ToString());
        } 
        catch (SocketException se) 
        {
            FormattedMessageBox.Show("SocketException : {0}", se.ToString());
        } 
        catch (Exception e) 
        {
            FormattedMessageBox.Show("Unexpected exception : {0}", e.ToString());
        }

    } 
    catch (Exception e) 
    {
        MessageBox.Show(e.ToString());
    }
}

在收到回答說這可能是服務器方面的問題之后，我將服務器降至最低限度。 問題仍在發生。 服務器接收並確認了第一條消息，但從未收到第二條消息。 這是服務器代碼：

import json
import threading

import socketserver
import time

with open('CAPS_TWMS_config.json', 'rt') as c:
    caps_config = json.load(c)

# We are listening on this port and all defined IP addresses
# listenPort = 5001
listenPort = caps_config["listen_port"]

# Were to send the information to.
clientIPAddress = '127.0.0.1'   # socket.gethostbyname('client')
# clientPort = 12345
clientPort = caps_config["send_port"]

dsnName = caps_config["dsn_name"]

# Message sequence number
sequence_num = 1
exit_app = False

class ListenSocketHandler(socketserver.BaseRequestHandler):
    """
    The RequestHandler class for our server.

    It is instantiated once per connection to the server, and must
    override the handle() method to implement communication to the
    client.
    """
    def __init__(self, request, client_address, this_server):
        socketserver.BaseRequestHandler.__init__(self, request, client_address, this_server)
        self.timeout = 10

    def handle(self):
        try:
            data = self.request.recv(1024).decode()
            print (str.format("dataString[21]: {0}; dataString[24:26]: {1}", data[21], data[24:26]))
            print ('ListenSocketHandler recv()-> "%s"' % data)
            print ('ListenSocketHandler recv().length-> "%d"' % len(data))

            if len(data) > 0:
                self.request.send("I got a message!".encode())
                return
        except Exception as value:
            print('ListenSocketHandler - %s' % str(value))

        return


class ListenServer(socketserver.ThreadingMixIn, socketserver.TCPServer):
    """
    The multi-threaded server that will spawn threads running the Socket Handler for each
    connection
    """
    pass

if __name__ == '__main__':

    try:
        # Create the Server Handler for connections to this computer listening on all IP addresses,
        # change '' to 'x.x.x.x'  to listen on a specific IP network.  This class will listen for messages    # from CAPS.
        server = ListenServer(('', listenPort), ListenSocketHandler)
        ip, port = server.server_address

        # Start a thread with the server -- that thread will then start one
        # more thread for each request
        server_thread = threading.Thread(target=server.serve_forever)
        # Exit the server thread when the main thread terminates
        server_thread.setDaemon(True)
        server_thread.start()

        while not exit_app:
            time.sleep(1)

        print ('Out of main loop.')
        server.shutdown()
        server.server_close()
    except Exception as value:
        print("Failed to do something: %s", str(value))

Answer 1

不，您無需執行任何操作即可發送多個消息。

聞起來好像服務器由於某種原因斷開連接，但是您沒有顯示該代碼