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TCP/IP Connection with Multiple Threads Speaking for Chat Application

i have a TCP Chat Server code sample like this, it creates multiple threads correctly, but it doesn't send the message to all threads. I want the message to be sent accross all threads, like a group chat. Can you help me?
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net;
using System.Net.Sockets;
using System.Threading;
class NewClient
{
public Socket newServerSocket;
public NewClient(Socket client)
{
this.newServerSocket = client;
}
public void speakWithClient()
{
int recv;
byte[] data = new byte[1024];
IPEndPoint clientep = (IPEndPoint) newServerSocket.RemoteEndPoint;
Console.WriteLine("Connected with {0} at port {1}",
clientep.Address, clientep.Port);
string welcome = "Welcome to my test server";
data = Encoding.ASCII.GetBytes(welcome);
newServerSocket.Send(data, data.Length,SocketFlags.None);
Right here, it sends the given message back to the client, but it doesn't send the message to all threads.
while (true)
{
data = new byte[1024];
recv = newServerSocket.Receive(data);
if (recv == 0)
break;
Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv));
newServerSocket.Send(data, recv, SocketFlags.None);
}
Console.WriteLine("Disconnected from {0}",
clientep.Address);
newServerSocket.Close();
}
}
class SimpleTcpSrvr
{
public static void Main()
{
int recv;
byte[] data = new byte[1024];
IPEndPoint ipep = new IPEndPoint(IPAddress.Any,9060);
Socket newsock = new Socket(AddressFamily.InterNetwork,
SocketType.Stream,
ProtocolType.Tcp);
newsock.Bind(ipep);
newsock.Listen(10);
Console.WriteLine("Waiting for a client...");
while (true)
{
Socket client = newsock.Accept();
NewClient threadliclient = new NewClient(client);
Thread newthread = new Thread(new ThreadStart(threadliclient.speakWithClient));
newthread.Start();
}
}
}

It's been a while since I've done any socket programming, but... don't you need to keep a list of your client sockets and loop through them every time you receive a message?
public static List<Socket> Clients = new List<Socket>();
while (true)
{
Socket client = newsock.Accept();
Clients.Add(client);
NewClient threadliclient = new NewClient(client);
Thread newthread = new Thread(new ThreadStart(threadliclient.speakWithClient));
newthread.Start();
}
public void speakWithClient()
{
int recv;
byte[] data = new byte[1024];
IPEndPoint clientep = (IPEndPoint) newServerSocket.RemoteEndPoint;
Console.WriteLine("Connected with {0} at port {1}", clientep.Address, clientep.Port);
string welcome = "Welcome to my test server";
data = Encoding.ASCII.GetBytes(welcome);
newServerSocket.Send(data, data.Length,SocketFlags.None);
while (true)
{
data = new byte[1024];
recv = newServerSocket.Receive(data);
if (recv == 0)
break;
Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv));
foreach (Socket client in SimpleTcpSrvr.Clients)
{
client.Send(data, recv, SocketFlags.None);
}
}

Why I can send data from TCP Client to Server, but not vice versa?

I wrote an asynchronous TCP server-client in C#. Both programs run successfully when I test them in one computer (server and client run simultaneously in the same machine). But when tested in two different computers, server-client connection is established and the client is able to send data to server, but the server seems to be not sending anything to its client.
By using TCPView, I know that both server and client is receiving/sending data as expected. I thought it was firewall blocking them, I've disabled it and no use. What's wrong with my code?
Server:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net.Sockets;
using System.Net;
// Server code
namespace ChatConsole
{
class Program
{
static Socket serverSocket, clientSocket;
static byte[] buffer;
const int defaultBufferSize = 1024;
static void Main(string[] args)
{
try
{
Console.WriteLine("This is server.");
// Create a new server socket.
serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
// Create IP End Point.
IPEndPoint ep = new IPEndPoint(IPAddress.Any, 1001);
// Bind endpoint to socket.
serverSocket.Bind(ep);
// Start listening for incoming client.
serverSocket.Listen(4);
// Execute callback method when client request connection.
serverSocket.BeginAccept(new AsyncCallback(AcceptCallback), null);
while (true) { }
}
catch(Exception ex)
{
Console.WriteLine("from Main(): " + ex.Message);
}
}
private static void AcceptCallback(IAsyncResult ar)
{
try
{
// Store client socket handle.
clientSocket = serverSocket.EndAccept(ar);
Console.WriteLine("Client {0} joined.", clientSocket.RemoteEndPoint);
// Welcome the client when connection established.
buffer = Encoding.ASCII.GetBytes("Hello from server!");
clientSocket.BeginSend(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(SendCallback), null);
// Begin receiving data from connected client.
buffer = new byte[1024];
clientSocket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), null);
}
catch (Exception ex)
{
Console.WriteLine("from AcceptCallback(): " + ex.Message);
}
}
private static void SendCallback(IAsyncResult ar)
{
// Terminate current send session.
clientSocket.EndSend(ar);
Console.WriteLine("Replied.");
}
private static void ReceiveCallback(IAsyncResult ar)
{
try
{
// Store the length of received data.
int received = clientSocket.EndReceive(ar);
if (received == 0)
return;
// Convert the received data to string then print in the console.
Array.Resize<byte>(ref buffer, received);
string text = Encoding.ASCII.GetString(buffer);
Console.WriteLine(text);
Array.Resize<byte>(ref buffer, defaultBufferSize);
// Send back message from the client.
byte[] data = Encoding.ASCII.GetBytes("from server: " + text);
clientSocket.BeginSend(data, 0, data.Length, SocketFlags.None, new AsyncCallback(SendCallback), null);
clientSocket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), null);
}
catch (Exception ex)
{
Console.WriteLine("from ReceiveCallback(): " + ex.Message);
}
}
}
}
Client:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net.Sockets;
using System.Net;
// Client code
namespace ChatConsoleClient
{
class Program
{
static Socket clientSocket;
static IPEndPoint ep;
static byte[] buffer;
const int defaultBufferSize = 1024;
static void Main(string[] args)
{
try
{
Console.WriteLine("This is client.");
// Create new socket for client.
clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
// Ask for server IP address.
string IP = Console.ReadLine();
// Create endpoint to be connected.
ep = new IPEndPoint(IPAddress.Parse(IP), 1001);
// Start connecting to the server.
clientSocket.BeginConnect(ep, new AsyncCallback(ConnectCallback), null);
buffer = new byte[1024];
clientSocket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), null);
while (true)
{
string text = Console.ReadLine();
byte[] data = Encoding.ASCII.GetBytes(text);
clientSocket.BeginSend(data, 0, data.Length, SocketFlags.None, new AsyncCallback(SendCallback), null);
}
}
catch (Exception ex)
{
Console.WriteLine("from Main(): " + ex.Message);
}
}
private static void ReceiveCallback(IAsyncResult ar)
{
int received = clientSocket.EndReceive(ar);
if (received == 0)
return;
// Convert the received data to string then print in the console.
Array.Resize<byte>(ref buffer, received);
string text = Encoding.ASCII.GetString(buffer);
Console.WriteLine(text);
Array.Resize<byte>(ref buffer, defaultBufferSize);
clientSocket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), null);
}
private static void SendCallback(IAsyncResult ar)
{
clientSocket.EndSend(ar);
}
private static void ConnectCallback(IAsyncResult ar)
{
clientSocket.EndConnect(ar);
}
}
}

I have checked client and server running in two different systems but both of them having the same IP series and it works

C# SendData sends random times

I am trying to create a program where a server communicates to clients and give them commands about what to do. But when I connect multiple clients it sends the commands to the client multiple random times. My current code:
using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
namespace Server
{
class Program
{
private static byte[] _buffer = new byte[1024];
private static List<Socket> _clientSockets = new List<Socket>();
private static int SERVERPORT = 5555;
private static Socket _serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
private static String command;
static void Main(string[] args)
{
Thread serverThread = new Thread(new ThreadStart(SetupServer));
Thread readThread = new Thread(new ThreadStart(checkInput));
serverThread.Start();
readThread.Start();
}
private static void SetupServer()
{
Console.WriteLine("Setting up server...");
_serverSocket.Bind(new IPEndPoint(IPAddress.Any, SERVERPORT));
_serverSocket.Listen(100);
_serverSocket.BeginAccept(new AsyncCallback(AcceptCallback), null);
}
private static void AcceptCallback(IAsyncResult AR)
{
while (true)
{
if (_serverSocket != null)
{
try
{
Socket socket = _serverSocket.EndAccept(AR);
_clientSockets.Add(socket);
Console.WriteLine("Client conntected");
}
catch
{
}
}
if (command != null)
{
byte[] data = Encoding.ASCII.GetBytes(command);
foreach (Socket s in _clientSockets)
{
s.BeginSend(data, 0, data.Length, SocketFlags.None, new AsyncCallback(SendCallback), s);
}
}
command = null;
_serverSocket.BeginAccept(new AsyncCallback(AcceptCallback), null);
}
}
private static void ReceiveCallback(IAsyncResult AR)
{
Socket socket = (Socket)AR.AsyncState;
//int received = socket.EndReceive(AR);
//byte[] dataBuf = new byte[received];
//Array.Copy(_buffer, dataBuf, received);
//string text = Encoding.ASCII.GetString(dataBuf);
string response = string.Empty;
response = Console.ReadLine();
byte[] data = Encoding.ASCII.GetBytes(response);
socket.BeginSend(data, 0, data.Length, SocketFlags.None, new AsyncCallback(SendCallback), socket);
socket.BeginReceive(_buffer, 0, _buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), socket);
}
private static void SendCallback(IAsyncResult AR)
{
try {
Socket socket = (Socket)AR.AsyncState;
socket.EndSend(AR);
}
catch {
}
}
public static void checkInput()
{
while (true)
{
command = Console.ReadLine();
}
}
}
}
An example. I start the server and start 3 clients next. This is the output:
I am totally clueless why it sends random times. Also why is there a double 2 on console #2. Thanks in advance!

This caused the problem:
if (command != null)
{
byte[] data = Encoding.ASCII.GetBytes(command);
foreach (Socket s in _clientSockets)
{
s.BeginSend(data, 0, data.Length, SocketFlags.None, new AsyncCallback(SendCallback), s);
}
}
command = null;
I added this piece of code to the readThread thread.
public static void checkInput()
{
while (true)
{
command = Console.ReadLine();
Console.WriteLine("Sending");
byte[] data = Encoding.ASCII.GetBytes(command);
foreach (Socket s in _clientSockets)
{
s.BeginSend(data, 0, data.Length, SocketFlags.None, new AsyncCallback(SendCallback), s);
}
command = null;
}
}
this solved it.

Connecting PCs with Sockets

I want to write a programm where multiple clients can join on a server. For now the clients are only able to ask for the servertime, which works perfectly fine, as long as the client and the server are on the same pc. I'm pretty sure that I have to change the EndPoint in the Connect() Method of the client, but I don't know what i should change it to.
Please help me to find a solution for this.
I have this code on my server:
using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.Net.Sockets;
namespace Multiple_Clients
{
class Program
{
private static int port = 4567;
private static byte[] _buffer = new byte[1024];
private static List<Socket> _clientSockets = new List<Socket>();
private static Socket _serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
static void Main(string[] args)
{
Console.Title = "Server";
setupServer();
Console.ReadLine();
}
private static void setupServer()
{
Console.WriteLine("Setting up server...");
_serverSocket.Bind(new IPEndPoint(IPAddress.Any, port));
_serverSocket.Listen(500);
_serverSocket.BeginAccept(new AsyncCallback(acceptCallback), null);
}
private static void acceptCallback(IAsyncResult AR)
{
Socket socket = _serverSocket.EndAccept(AR);
_clientSockets.Add(socket);
Console.WriteLine("Client connected");
socket.BeginReceive(_buffer, 0, _buffer.Length, SocketFlags.None, new AsyncCallback(receiveCallback), socket);
_serverSocket.BeginAccept(new AsyncCallback(acceptCallback), null);
}
private static void receiveCallback(IAsyncResult AR)
{
Socket socket = (Socket)AR.AsyncState;
int received = socket.EndReceive(AR);
byte[] dataBuf = new byte[received];
Array.Copy(_buffer, dataBuf, received);
string text = Encoding.ASCII.GetString(dataBuf);
Console.WriteLine("Text received: " + text);
string response = string.Empty;
if (text.ToLower() != "get time")
{
response = "Invalid Request";
}
else
{
response = DateTime.Now.ToLongTimeString();
}
byte[] data = Encoding.ASCII.GetBytes(response);
socket.BeginSend(data, 0, data.Length, SocketFlags.None, new AsyncCallback(sendCallback), socket);
socket.BeginReceive(_buffer, 0, _buffer.Length, SocketFlags.None, new AsyncCallback(receiveCallback), socket);
}
private static void sendCallback(IAsyncResult AR)
{
Socket socket = (Socket)AR.AsyncState;
socket.EndSend(AR);
}
}
}
And this on my client
using System;
using System.Text;
using System.Net;
using System.Net.Sockets;
namespace Multiple_Clients
{
class Program
{
private static int port = 4567;
private static Socket _clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
static void Main(string[] args)
{
Console.Title = "Client";
connect();
sendLoop();
Console.ReadLine();
}
private static void connect()
{
int attempts = 0;
while(!_clientSocket.Connected)
{
try
{
attempts++;
_clientSocket.Connect(IPAddress.Loopback, port);
}
catch(SocketException)
{
Console.Clear();
Console.WriteLine("Connection attempts: " + attempts.ToString());
}
}
Console.Clear();
Console.WriteLine("Connected");
}
private static void sendLoop()
{
while (true)
{
Console.Write("Enter a request:");
string req = Console.ReadLine();
byte[] buffer = Encoding.ASCII.GetBytes(req);
_clientSocket.Send(buffer);
byte[] receivedBuf = new byte[1024];
int rec = _clientSocket.Receive(receivedBuf);
byte[] data = new byte[rec];
Array.Copy(receivedBuf, data, rec);
Console.WriteLine("Received: " + Encoding.ASCII.GetString(data));
}
}
}
}
Any suggestions on how to improve this question are welcome.
Thank you very much for helping me!

Your client allways connect to IPAddress.Loopback ... in fact the local IP Address 127.0.0.1. Exchange IPAddress.Loopback to the real IPAdress of your server, e. g. IPAddress.Parse("192.168.?.?") ...!

TCP Server with bi-directional communication

I have attempted to create a TCP service that is able to achieve what I wish but sadly I am getting stuck at the last hurdle.
The Scenario:
A single server instance is running with 10 clients all connected, a client will send a command, and receive the response. This is all working fine. However the last scenario isn't working
When a client issues an "UPDATE" command, the server should then send a message back to all connected clients that they need to do something.
Example Comms:
1
Client A GetTime -----> Server
Client A <----- Time is... Server
2
Client A UPDATE ------> Server
Client A <------- Ack Server
Client A <------- DoUpdate Server
Client B <------- DoUpdate Server
Client C <------- DoUpdate Server
Comms 1 abover works, mainly because of the call to send and call to reeive, but for comms 2 I cannot workout how I can achieve this, at least not without opening a second port for the communication which isn't ideal.
Current attempt based on Microsoft Article
Server
class Program
{
public static int Main(String[] args)
{
AsynchronousSocketListener.StartListening();
return 0;
}
}
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 static void StartListening()
{
// Data buffer for incoming data.
//var 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, 3030);
// Create a TCP/IP socket.
var listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
// Bind the socket to the local endpoint and listen for incoming connections.
try
{
listener.Bind(new IPEndPoint(IPAddress.Any, 3030));
//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((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.
var listener = (Socket)ar.AsyncState;
Socket handler = listener.EndAccept(ar);
// Create the state object.
var state = new StateObject {WorkSocket = handler};
handler.BeginReceive(state.Buffer, 0, StateObject.BufferSize, 0, ReadCallback, state);
}
public static void ReadCallback(IAsyncResult ar)
{
// Retrieve the state object and the handler socket
// from the asynchronous state object.
var 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.
var content = state.Sb.ToString();
if (content.IndexOf("<EOF>", StringComparison.Ordinal) > -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, ReadCallback, state);
}
}
}
private static void Send(Socket handler, String data)
{
// Convert the string data to byte data using ASCII encoding.
var byteData = Encoding.ASCII.GetBytes(data);
// Begin sending the data to the remote device.
handler.BeginSend(byteData, 0, byteData.Length, 0, SendCallback, handler);
}
private static void SendCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
var 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;
}
* */
}
Client Code
class Program
{
public static int Main(String[] args)
//static void Main(string[] args)
{
Console.Title = "Client ";
AsynchronousClient.StartClient();
Console.ReadLine();
return 0;
}
}
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 = 3030;
// ManualResetEvent instances signal completion.
private static readonly ManualResetEvent ConnectDone =
new ManualResetEvent(false);
private static readonly ManualResetEvent SendDone =
new ManualResetEvent(false);
private static readonly ManualResetEvent ReceiveDone =
new ManualResetEvent(false);
// The response from the remote device.
private static String _response = String.Empty;
public 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");
//??IPHostEntry ipHostInfo = Dns.Resolve("localhost");
//??IPAddress ipAddress = ipHostInfo.AddressList[0];
//??IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);
// Create a TCP/IP socket.
var client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
// Connect to the remote endpoint.
//client.BeginConnect(remoteEP,
//new AsyncCallback(ConnectCallback), client);
var remoteEP = new IPEndPoint(IPAddress.Parse("127.0.0.1"), Port);
client.BeginConnect(remoteEP, ConnectCallback, client);
ConnectDone.WaitOne();
// set receive to another thread so we can constantly receive, doesn't work as intended
//var thread = new Thread(() => ReadThread(client));
//thread.Start();
// Send test data to the remote device.
Send(client, "This is a test<EOF>");
SendDone.WaitOne();
//test remove
// 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());
}
}
// doesn't work as expected
private static void ReadThread(object ar)
{
var client = (Socket)ar;
while (true)
{
Receive(client);
ReceiveDone.WaitOne();
// Write the response to the console.
Console.WriteLine("Response received : {0}", _response);
}
}
private static void ConnectCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
var client = (Socket)ar.AsyncState;
// Complete the connection.
client.EndConnect(ar);
Console.WriteLine("Socket connected to {0}", client.RemoteEndPoint);
// 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.
var state = new StateObject {WorkSocket = client};
// Begin receiving the data from the remote device.
client.BeginReceive(state.Buffer, 0, StateObject.BufferSize, 0, 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.
var 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, 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.
var byteData = Encoding.ASCII.GetBytes(data);
// Begin sending the data to the remote device.
client.BeginSend(byteData, 0, byteData.Length, 0, SendCallback, client);
}
private static void SendCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
var 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;
}
*/
}
Previous system that worked
Server:
class Program
{
private static byte[] buffer = new byte[1024];
public static Socket _serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
public static List<Socket> clientSockets = new List<Socket>();
static void Main(string[] args)
{
Console.Title = "Server, " + clientSockets.Count + " clients are connected";
SetupServer();
Console.ReadLine();
}
public static void SetupServer()
{
Console.WriteLine("Setting up server...");
_serverSocket.Bind(new IPEndPoint(IPAddress.Any, 3030));
_serverSocket.Listen(10);
_serverSocket.BeginAccept(AcceptCallback, null);
Console.ReadLine();// stops cmd from closing
}
public static void AcceptCallback(IAsyncResult AR)
{
Socket socket = _serverSocket.EndAccept(AR);
if (!clientSockets.Contains(socket))
clientSockets.Add(socket);
IPEndPoint remoteIPEndPoint = socket.RemoteEndPoint as IPEndPoint;
Console.WriteLine(remoteIPEndPoint.Address);
Console.WriteLine("Client Connected");
Console.Title = "Server, " + clientSockets.Count + " clients are connected";
socket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, RecieveCallBack, socket);
_serverSocket.BeginAccept(AcceptCallback, null);
}
private static void RecieveCallBack(IAsyncResult AR)
{
var socket = (Socket)AR.AsyncState;
int received = socket.EndReceive(AR);
var databuff = new byte[received];
Array.Copy(buffer, databuff, received);
string s = Encoding.ASCII.GetString(databuff);
Console.WriteLine("Text Received: " + s);
string response = string.Empty;
switch (s.ToLower())
{
case "get time":
response = DateTime.Now.ToLongTimeString();
break;
case "hello":
response = "olleh";
break;
case "update clients":
response = "";
SendData("Ack", socket);
doUpdateClients();
break;
default:
response = "Invavlid Request";
break;
}
SendData(response, socket);
}
private static void SendData(string Data, Socket socket)
{
byte[] data = Encoding.ASCII.GetBytes(Data);
socket.BeginSend(data, 0, data.Length, SocketFlags.None, sendCallback, socket);
socket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, RecieveCallBack, socket);
}
private static void doUpdateClients()
{
// need to send an update message to all the clients
var upd = new Thread((UpdateClients));
upd.Start();
}
private static void UpdateClients()
{
Thread.Sleep(5000);
foreach (var sock in clientSockets)
{
SendData("UpdateClients", sock);
}
}
private static void sendCallback(IAsyncResult AR)
{
var socket = (Socket)AR.AsyncState;
socket.EndSend(AR);
}
//
}
}
Client:
class Program
{
private static byte[] buffer = new byte[1024];
public static Socket _clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
static void Main(string[] args)
{
Console.Title = "Client ";
LoopConnect();
//ReceiveLoopStart();
//_clientSocket.Listen(10);
SendLoop();
Console.ReadLine();
}
private static void LoopConnect()
{
while (!_clientSocket.Connected)
{
try
{
_clientSocket.Connect(IPAddress.Parse("127.0.0.1"), 3030);
}
catch (SocketException se)
{
}
}
Console.WriteLine("Connected");
}
private static void ReceiveLoopStart()
{
//_clientSocket.Bind(new IPEndPoint(IPAddress.Any, 3030));
//_clientSocket.Listen(10);
_clientSocket.BeginAccept(AcceptCallback, null);
Thread receiveThread = new Thread(ReceiveLoop);
receiveThread.Start();
}
private static void ReceiveLoop()
{
_clientSocket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, RecieveCallBack, _clientSocket);
_clientSocket.BeginAccept(AcceptCallback, null);
}
private static void RecieveCallBack(IAsyncResult AR)
{
int received = _clientSocket.EndReceive(AR);
var databuff = new byte[received];
Array.Copy(buffer, databuff, received);
string s = Encoding.ASCII.GetString(databuff);
Console.WriteLine("Text Received: " + s);
string response = string.Empty;
switch (s.ToLower())
{
case "get time":
response = DateTime.Now.ToLongTimeString();
break;
case "hello":
response = "olleh";
break;
default:
response = "Invavlid Request";
break;
}
}
public static void AcceptCallback(IAsyncResult AR)
{
Socket socket = _clientSocket.EndAccept(AR);
Console.WriteLine("Client Connected");
socket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, RecieveCallBack, socket);
_clientSocket.BeginAccept(AcceptCallback, null);
}
private static void SendLoop()
{
while (true)
{
Console.Write("Enter Request: ");
string req = Console.ReadLine();
var buffer = Encoding.ASCII.GetBytes(req);
_clientSocket.Send(buffer);
var tempBuff = new byte[1024];
int rec = _clientSocket.Receive(tempBuff);
var data = new byte[rec];
Array.Copy(tempBuff, data, rec);
Console.WriteLine("Received: " + Encoding.ASCII.GetString(data));
}
}
}
}

I don't have an example up my sleeve here in C# but what you need to learn is to use the select api.
You only need a single thread to do this. You use the same thread to process all sockets that are in use at any point in time.
If nobody is connected you only have the listening socket. And you then only use the select api to watch what happens on that socket. Select is a blocking call when no timeout is specified. If data is available, then that means that you can call accept. The result of accept is as you know another socket. You now use 2 sockets in select. Again select will block until one of those sockets has data. Perhaps the listening socket again, so you get another socket after calling accept. You now use 3 sockets in select. Suppose now one of the accept sockets have data available you will see that by the using the select api properly. And you can then use any of those sockets to send something over it, except of course the listening socket that is not intended for sending.
More info can be found here :
http://www.codeproject.com/Articles/20066/A-scalable-client-server-using-select-socket-funct
It uses what I explained and gives more elaborate explanations too.

I'm not getting in to your design , but it seems like you can't even reference the other clients.
why don't you save a collection of sockets like so :
private List<Socket> _handlers = new List<Socket>();
public static void AcceptCallback(IAsyncResult ar)
{
Socket handler = listener.EndAccept(ar);
var state = new StateObject {WorkSocket = handler};
handlers.Add(handler);
handler.BeginReceive(state.Buffer, 0, StateObject.BufferSize, 0, ReadCallback, state);
}
And then on receive according to the message type or whatever you should notify these clients.( all of them not just the one currently passed to the ReciveCallback.
public static void ReadCallback(IAsyncResult ar)
{
if("<EOF>")
{
foreach(var h in _handlers)
{
Send(h,data);
}
}
}