Server Socket Programming in C#, How To Start

Socket programming have two part
I. Server
II. Client.

I. Server:
To start server need to follow some steps, these are:
i. First create a IPEndPoint
[e.g. IPEndPoint ipEnd = new IPEndPoint(IPAddress.Any, port);]

ii. Create a socket object.
[Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP);]

iii. Bind socket with IPEndPoint.
[sock.Bind(ipEnd);]

iv. Place socket in Listen mode (to accept call of client)
[sock.Listen(maxClientReceived);]

v. When any call comes from client Accept that call.
[Socket clientSock = sock.Accept();]
At that position Accept() return a new socket to continue communication with called client. By that socket Client-Server communication continue.

To send some data (in byte array form) to client from server just write
clientSock.send(byteArrayData);

To receive client data just write
int receivedLen= clientSock.Receive(clientData);
Receive() function reads data in byte array form from client socket and writes to ‘clientData’ array, and return integer value how much bytes has received.

I’m giving complete code of a simple server socket below:-

using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.Net.Sockets;
namespace beginSocketServer
{
class Program
{
static void Main(string[] args)
{
IPEndPoint ipEnd = new IPEndPoint(IPAddress.Any, 5656);
Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP);
sock.Bind(ipEnd);
sock.Listen(100);
Socket clientSock = sock.Accept();
byte[] clientData = new byte[1024];
int receivedBytesLen = clientSock.Receive(clientData);
string clientDataInString = Encoding.ASCII.GetString(clientData, 0, receivedBytesLen);
Console.WriteLine("Received Data {0}", clientDataInString);
string clientStr = "Client Data Received";
byte[] sendData = new byte[1024];
sendData= Encoding.ASCII.GetBytes(clientStr);
clientSock.Send(sendData);
clientSock.Close();
Console.ReadLine();
}
}
}

To run that server code you don’t need to write client code just open a webbrowser and write (I’ve use Mozilla Firefox or Chrome) :

http://localhost:5656/

Server console output was:

Received Data GET / HTTP/1.1Host: localhost:5656User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.7) Gecko/20070914 Firefox/2.0.0.7Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,
*/*;q=0.5Accept-Language: en-us,en;q=0.5Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7Keep-Alive: 300Connection: keep-alive

And in web browser output was:

Client Data Received.

Ok, Simple server socket application has done. Next will give simple client socket application for beginner.