client/server problem [modified]

staticv

I have developed a simple client/server app which echoes whatever text the clients sends to the server. Currently, it echoes text only to one client, which has send the text, but I want it to send to all the clients connected. The problem is that when one client writes to the server after that the client waits for receiving and as soon it has received the echo it starts writing to the server, so if some other client sends to the server, and the server echoes back to all the clients, only those will receive the message which are waiting for reading, but none are except the client which has send the message to the server. So how to overcome this? Btw, it is a console application, is it possible to do in it? I guess I explained it correctly. If not, then please ask again :)

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modified on Monday, January 26, 2009 9:59 AM

Mustafa Ismail Mustafa · modified on Monday, January 26, 2009 9:59 AM

It sounds like you're trying to emulate a group chat/IM session. You're going to need to register all the users who "log" on to your server and are interested in the echo. The Observer pattern is precisely what you are looking for: http://www.dofactory.com/Patterns/PatternObserver.aspx[^] and http://en.wikipedia.org/wiki/Observer_pattern[^] After reading that you should have a clue of what you ought to do but in plain English what you're doing is that you're making a list of all the registrants and instead of echoing to one, you're broadcasting the echo to each and everyone in the list. Post back if you need more help.

staticv

Well, whenever a user is connected I store its connection and username in a hashtable, and when the server receives a message, I create a for loop and gets everyone's specific stream and then send the message to them. But at that time the clients are waiting for the input, rather than reading what the server has send. Only that client reads who have send the message to the server. Do you want me to post the code? Heres the code for the server

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

public class ClientHandler
{
public TcpClient clientSocket;

public void RunClient()
{
// Create the stream classes
StreamReader readerStream = new StreamReader(clientSocket.GetStream());
NetworkStream writerStream = clientSocket.GetStream();

  string returnData = readerStream.ReadLine(); 
  string userName = returnData; 

  Console.WriteLine("Welcome " + userName + " to the Server"); 

  while (true) 
  { 
     returnData = readerStream.ReadLine(); 

     if (returnData.IndexOf("QUIT") > −1) 
     { 
        Console.WriteLine("Bye Bye " + userName); 
        break; 
     } 

     Console.WriteLine(userName + ": " + returnData); 
     returnData += "\\r\\n"; 

     byte\[\] dataWrite = Encoding.ASCII.GetBytes(returnData) 
     writerStream.Write(dataWrite,0,dataWrite.Length); 
  } 

  clientSocket.Close();

}
}

public class EchoServer
{
const int ECHO_PORT = 8080;

public static void Main(string [] arg)
{
try
{
// Bind the server to the local port
TcpListener clientListener = new TcpListener(ECHO_PORT);

     // Start to listen 
     clientListener.Start(); 

     Console.WriteLine("Waiting for connections…"); 

     while (true) 
     { 
        // Accept the connection 
        TcpClient client = clientListener.AcceptTcpClient(); 

        ClientHandler cHandler = new ClientHandler(); 

        // Pass value to the ClientHandler object 
        cHandler.clientSocket = client; 

        // Create a new thread for the client 
        Thread clientThread = new Thread(new ThreadStart(cHandler.RunClient)); 
        clientThread.Start(); 
     } 

     clientListener.Stop(); 
  } 
  catch(Exception exp)

Mustafa Ismail Mustafa

Three things: 1. Did you read the literature I posted? It'll really help you 2. Why are you using a Hashtable? 3. cHandler.clientSocket = client; See this? You're only ever responding to one and one client at any time, and if you don't mind me saying it, you're doing a bad job of it. Read the literature, it'll show you a really good way of doing things.

staticv

sorry I posted the old code :) heres the modified one where i send messages to all. btw i'm going to read the article you given while you tell me if the code is correct or not :)

void RunClient()
{
	// Create the stream classes
	StreamReader readerStream = new StreamReader(clientSocket.GetStream());
	NetworkStream writerStream = clientSocket.GetStream();

	string returnData = readerStream.ReadLine();
	string userName = returnData;
	
	// Add a user
	users.Add(userName, clientSocket);

	Console.WriteLine("Welcome " + userName + " to the Server");

	while (true)
	{
		returnData = readerStream.ReadLine();
		String tempData = returnData.ToLower();

		if (tempData.IndexOf("quit") > -1)
		{
			Console.WriteLine("Bye Bye " + userName);
			break;
		}

		Console.WriteLine(userName + ": " + returnData);
		returnData += "\\r\\n";

		byte\[\] dataWrite = Encoding.ASCII.GetBytes(returnData);
		
		TcpClient\[\] tcpClients = new TcpClient\[users.Count\];
		users.Values.CopyTo(tcpClients, 0);
		for (int i = 0; i < tcpClients.Length; i++)
		{
			NetworkStream tempWriteStream = tcpClients\[i\].GetStream();
			tempWriteStream.Write(dataWrite, 0, dataWrite.Length);
			tempWriteStream = null;
		}
	}

	clientSocket.Close();
}

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modified on Monday, January 26, 2009 10:43 AM

Mustafa Ismail Mustafa · modified on Monday, January 26, 2009 10:43 AM

OK, this is in the wrong forum now.

staticv

no, i changed the code :)

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Mustafa Ismail Mustafa

You did, from C# to C++/CLI which makes it in the wrong forum

staticv

it is C# :)

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