Asynchronous Client/Server Socket Example with C# (from MSDN library)

README

Sample codes from MSDN library about socket programming, specially the asynchronous approach.

Asynchronous Server Socket Example
http://msdn.microsoft.com/en-us/library/fx6588te.aspx

Asynchronous Client Socket Example
http://msdn.microsoft.com/en-us/library/bew39x2a.aspx

Using an Asynchronous Server Socket
http://msdn.microsoft.com/en-us/library/5w7b7x5f.aspx

Client.cs

// Asynchronous Client Socket Example
// http://msdn.microsoft.com/en-us/library/bew39x2a.aspx

using System;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.Text;

// State object for receiving data from remote device.
public class StateObject {
    // Client socket.
    public Socket workSocket = null;
    // Size of receive buffer.
    public const int BufferSize = 256;
    // Receive buffer.
    public byte[] buffer = new byte[BufferSize];
    // Received data string.
    public StringBuilder sb = new StringBuilder();
}

public class AsynchronousClient {
    // The port number for the remote device.
    private const int port = 11000;

    // ManualResetEvent instances signal completion.
    private static ManualResetEvent connectDone = 
        new ManualResetEvent(false);
    private static ManualResetEvent sendDone = 
        new ManualResetEvent(false);
    private static ManualResetEvent receiveDone = 
        new ManualResetEvent(false);

    // The response from the remote device.
    private static String response = String.Empty;

    private static void StartClient() {
        // Connect to a remote device.
        try {
            // Establish the remote endpoint for the socket.
            // The name of the 
            // remote device is "host.contoso.com".
            IPHostEntry ipHostInfo = Dns.Resolve("host.contoso.com");
            IPAddress ipAddress = ipHostInfo.AddressList[0];
            IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);

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

            // Connect to the remote endpoint.
            client.BeginConnect( remoteEP, 
                new AsyncCallback(ConnectCallback), client);
            connectDone.WaitOne();

            // Send test data to the remote device.
            Send(client,"This is a test<EOF>");
            sendDone.WaitOne();

            // Receive the response from the remote device.
            Receive(client);
            receiveDone.WaitOne();

            // Write the response to the console.
            Console.WriteLine("Response received : {0}", response);

            // Release the socket.
            client.Shutdown(SocketShutdown.Both);
            client.Close();
            
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }

    private static void ConnectCallback(IAsyncResult ar) {
        try {
            // Retrieve the socket from the state object.
            Socket client = (Socket) ar.AsyncState;

            // Complete the connection.
            client.EndConnect(ar);

            Console.WriteLine("Socket connected to {0}",
                client.RemoteEndPoint.ToString());

            // Signal that the connection has been made.
            connectDone.Set();
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }

    private static void Receive(Socket client) {
        try {
            // Create the state object.
            StateObject state = new StateObject();
            state.workSocket = client;

            // Begin receiving the data from the remote device.
            client.BeginReceive( state.buffer, 0, StateObject.BufferSize, 0,
                new AsyncCallback(ReceiveCallback), state);
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }

    private static void ReceiveCallback( IAsyncResult ar ) {
        try {
            // Retrieve the state object and the client socket 
            // from the asynchronous state object.
            StateObject state = (StateObject) ar.AsyncState;
            Socket client = state.workSocket;

            // Read data from the remote device.
            int bytesRead = client.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));

                // Get the rest of the data.
                client.BeginReceive(state.buffer,0,StateObject.BufferSize,0,
                    new AsyncCallback(ReceiveCallback), state);
            } else {
                // All the data has arrived; put it in response.
                if (state.sb.Length > 1) {
                    response = state.sb.ToString();
                }
                // Signal that all bytes have been received.
                receiveDone.Set();
            }
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }

    private static void Send(Socket client, 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.
        client.BeginSend(byteData, 0, byteData.Length, 0,
            new AsyncCallback(SendCallback), client);
    }

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

            // Complete sending the data to the remote device.
            int bytesSent = client.EndSend(ar);
            Console.WriteLine("Sent {0} bytes to server.", bytesSent);

            // Signal that all bytes have been sent.
            sendDone.Set();
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }
    
    public static int Main(String[] args) {
        StartClient();
        return 0;
    }
}

Server.cs

// Asynchronous Server Socket Example
// http://msdn.microsoft.com/en-us/library/fx6588te.aspx

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 {
    // 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 {
    // Thread signal.
    public static ManualResetEvent allDone = new ManualResetEvent(false);

    public AsynchronousSocketListener() {
    }

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

        // Establish the local endpoint for the socket.
        // The DNS name of the computer
        // running the listener is "host.contoso.com".
        IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
        IPAddress ipAddress = ipHostInfo.AddressList[0];
        IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 11000);

        // 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 (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;
    }
}

[email protected]

How to create a RESTful web service for Server.cs
Can you give the source code for that ?

How can I received dynamic message from server, I mean the message is not under a fixed size bytes array

hello sir, I have created server program using visual studio 2015 C#, i am connecting to esp2866. it gets connected. and send data to esp8266 but cant receive. when i use socket.receive( ) method , it waits for data to be received. but i dont want to wait for data. ho do i gete data automatically received?. I dont understand async method.
my code is:
`using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Net;
using System.Net.Sockets;
using System.IO;
using System.Threading;

namespace Wifi_Server_Client_Test
{
public partial class Form1 : Form
{
Socket sck, socket;
byte[] bytes = new byte[1024];

    public Form1()
    {
        InitializeComponent();
    }


    private void Form1_Load(object sender, EventArgs e)
    {
        // Setup Socket 
       
      //  sck.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
        txtHost.Text = GetLocalIP();
        btnStp.Enabled = false;
        btnCon.Enabled = true;
        btnSend.Enabled = false;
        // LISTEN FOR RECEPTION---------

        TcpListener server = new TcpListener(IPAddress.Parse(txtHost.Text), Convert.ToInt32(HostPort.Text));
        socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        //Start the server




    }

    private string GetLocalIP()
    {
        IPHostEntry Host;
        Host = Dns.GetHostEntry(Dns.GetHostName());
        foreach(IPAddress ip in Host.AddressList)
        {if (ip.AddressFamily == AddressFamily.InterNetwork)
                return ip.ToString();
     }
        return ("192.0.0.0");
    }

    private void Close_Click(object sender, EventArgs e)
    {
        Close();
    }

    private void Minimise_Click(object sender, EventArgs e)
    {
        WindowState = FormWindowState.Minimized;
    }


    private void btnCon_Click(object sender, EventArgs e)
    {
        //connecting to client
        
        IPHostEntry Host;
        Host = Dns.GetHostEntry(Dns.GetHostName());
        IPEndPoint remoteEP = new IPEndPoint(IPAddress.Parse(txtClient.Text), Convert.ToInt32(txtPort.Text));
        // Setup Socket
        sck = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        //connecting to client remote
       
        if (!sck.Connected)
        {
            sck.Connect(remoteEP);
            listMessage.Items.Add("Succssfully Connected to: " + remoteEP.ToString());
            btnStp.Enabled = true;
            btnCon.Enabled = false;
            btnSend.Enabled = true;
        }

        // Start listening and accept a client.  

        try { 
        // Setup a callback to be notified of connection requests
        int bytesRec = sck.Receive(bytes);
        listMessage.Items.Add("ESP8266 Said:" + Encoding.ASCII.GetString(bytes, 0, bytesRec));
            //--------------------------------------
        }
        catch(Exception ex) { listMessage.Items.Add(ex); }
    }

    private void btnSend_Click(object sender, EventArgs e)
    {
        //convert string message to  byte[]
        ASCIIEncoding aEncoding = new ASCIIEncoding();
        byte[] sendingMessage = new byte[1500];
        sendingMessage = aEncoding.GetBytes(txtMessage.Text);
        //sending encodded byte
        sck.Send(sendingMessage);
        //sending encodded byte
        listMessage.Items.Add("Me: " + txtMessage.Text);
        txtMessage.Text = "";
    }


    private void btnStp_Click(object sender, EventArgs e)
    {
        sck.Shutdown(SocketShutdown.Both);
        sck.Disconnect(true);
        sck.Close();
        listMessage.Items.Add("Disconnected");
       
        btnStp.Enabled = false;
        btnCon.Enabled = true;
        btnSend.Enabled = false;
        
    }

   
}

}
HELP PLEASE.

THANK YOU.

can i use above code to carry voice information? and i need it to go through the UPD protocol.

can i use above code as windows service? i tried but having issues with while loop and allDone.Set() and allDone.WaitOne()

can i use above code to carry voice information? and i need it to go through the UPD protocol.

Just convert the voice data to base64 and send it as text , then translate back it