如何識別和區分客戶端-服務器套接字應用程序中連接的客戶端？

Question

在有一個異步套接字服務器並且連接了n個客戶端的情況下，在服務器端如何區分客戶端？ 我需要知道數據來自哪個客戶端。 注意 - append 可能無法作為請求的標識符。

客戶端在運行時創建：

public void CreateSockets()
        {
             Parallel.For(1, Convert.ToInt32(numericUpDown1.Value) + 1, i =>
            {
                new Thread(() => Connect(i)).Start();
            });
        }

簡化的客戶端創建循環：

public void Connect(int i)
{
    ClientSocket[i] = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

        try
        {
            ClientSocket[i].Connect(ip, port);
        }
        catch (SocketException sex)
        {
            Console.WriteLine(sex);
        }

     RequestLoop();
}

sockets 正在創建、連接並正在向服務器發送數據。 服務器直接來自異步套接字服務器的 MS 站點示例。

using System;  
using System.Net;  
using System.Net.Sockets;  
using System.Text;  
using System.Threading;  
  
// State object for reading client data asynchronously  
public class StateObject
{
    // 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();

    // Client socket.
    public Socket workSocket = null;
}  
  
public class AsynchronousSocketListener
{
    // Thread signal.  
    public static ManualResetEvent allDone = new ManualResetEvent(false);

    public AsynchronousSocketListener()
    {
    }

    public static void StartListening()
    {
        // Establish the local endpoint for the socket.  
        // The DNS name of the computer  
        // running the listener is "host.contoso.com".  
        IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName());  
        IPAddress ipAddress = ipHostInfo.AddressList[0];  
        IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 11000);  
  
        // Create a TCP/IP socket.  
        Socket listener = new Socket(ipAddress.AddressFamily,  
            SocketType.Stream, ProtocolType.Tcp );  
  
        // Bind the socket to the local endpoint and listen for incoming connections.  
        try {  
            listener.Bind(localEndPoint);  
            listener.Listen(100);  
  
            while (true) {  
                // Set the event to nonsignaled state.  
                allDone.Reset();  
  
                // Start an asynchronous socket to listen for connections.  
                Console.WriteLine("Waiting for a connection...");  
                listener.BeginAccept(
                    new AsyncCallback(AcceptCallback),  
                    listener );  
  
                // Wait until a connection is made before continuing.  
                allDone.WaitOne();  
            }  
  
        } catch (Exception e) {  
            Console.WriteLine(e.ToString());  
        }  
  
        Console.WriteLine("\nPress ENTER to continue...");  
        Console.Read();  
  
    }

    public static void AcceptCallback(IAsyncResult ar)
    {
        // Signal the main thread to continue.  
        allDone.Set();  
  
        // Get the socket that handles the client request.  
        Socket listener = (Socket) ar.AsyncState;  
        Socket handler = listener.EndAccept(ar);  
  
        // Create the state object.  
        StateObject state = new StateObject();  
        state.workSocket = handler;  
        handler.BeginReceive( state.buffer, 0, StateObject.BufferSize, 0,  
            new AsyncCallback(ReadCallback), state);  
    }

    public static void ReadCallback(IAsyncResult ar)
    {
        String content = String.Empty;  
  
        // Retrieve the state object and the handler socket  
        // from the asynchronous state object.  
        StateObject state = (StateObject) ar.AsyncState;  
        Socket handler = state.workSocket;  
  
        // Read data from the client socket.
        int bytesRead = handler.EndReceive(ar);  
  
        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.  
                Console.WriteLine("Read {0} bytes from socket. \n Data : {1}",  
                    content.Length, 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 static 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 static void SendCallback(IAsyncResult ar)
    {
        try
        {
            // Retrieve the socket from the state object.  
            Socket handler = (Socket) ar.AsyncState;  
  
            // Complete sending the data to the remote device.  
            int bytesSent = handler.EndSend(ar);  
            Console.WriteLine("Sent {0} bytes to client.", bytesSent);  
  
            handler.Shutdown(SocketShutdown.Both);  
            handler.Close();  
  
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());  
        }  
    }

    public static int Main(String[] args)
    {
        StartListening();  
        return 0;  
    }
}

Answer 1

srcip:srcport:dstip:dstport 的組合是唯一值。

使用該值來識別您的客戶。 當客戶端連接時，讓客戶端發送一個標識符。 在您的服務器中維護 state 將該組合映射到您的客戶端。

在 your.network 上的任何套接字上，您永遠不會有兩個相同的 this 值。 （具有相同 ip 地址的 private.networks 除外）。