I wrote a client-server app, this is a console chat application for many clients. When only one client is connected, the application works well, but when two or more clients are connected I have a bug, after sending one message to the second client, he lost connection to the server and only first client can send a message to the server...
I used Task for asynchronous operations like listening port and sending messages. When one client sends a message to the server, it adds it to the list messages and resends to all clients to refresh all windows.
Server application:
using System;
using System.Net;
using System.Net.Sockets;
using System.IO;
using System.Collections.Generic;
using System.Threading.Tasks;
namespace Server
{
class Program
{
private static List<Client> clients = new List<Client>();
private static TcpListener listener = null;
private static StreamReader reader = null;
private static StreamWriter writer = null;
private static List<Task> clientTasks = new List<Task>();
private static List<string> messages = new List<string>();
public static void Main()
{
Console.Title = "Server";
try
{
listener = new TcpListener(IPAddress.Parse("127.0.0.1"), 8080);
listener.Start();
Console.WriteLine("Server started...");
var connectTask = Task.Run(() => ConnectClients());
//var listenTask = Task.Run(() => ListenClients());
Task.WaitAll(connectTask);
}
catch (Exception e)
{
Console.WriteLine(e);
}
finally
{
if (listener != null)
{
listener.Stop();
}
}
}
private static void ConnectClients()
{
Console.WriteLine("Waiting for incoming client connections...");
while (true)
{
if (listener.Pending()) //if someone want to connect
{
clients.Add(new Client(listener.AcceptTcpClient(), "Client: " + (clients.Count + 1)));
Console.WriteLine(clients[clients.Count - 1].clientName + " connected to server.");
var newClientTask = Task.Run(() => HandleClient(clients[clients.Count - 1]));
clientTasks.Add(newClientTask); //start new task for new client
}
}
}
private static void HandleClient(Client TCPClient)
{
Console.WriteLine("Starting handle client");
string s = string.Empty;
writer = new StreamWriter(TCPClient.client.GetStream());
reader = new StreamReader(TCPClient.client.GetStream());
try
{
while (!(s = reader.ReadLine()).Equals("Exit") || (s == null))
{
if(!TCPClient.client.Connected)
{
Console.WriteLine("Client disconnected.");
clients.Remove(TCPClient);
}
Console.WriteLine("From client: " + TCPClient.clientName + " -> " + s);
messages.Add(TCPClient.clientName + ": " + s); //save new message
//Console.WriteLine(s);
foreach (Client c in clients) //refresh all connected clients
{
c.writer.WriteLine("%C"); //clear client
foreach (string msg in messages)
{
c.writer.WriteLine(msg);
c.writer.Flush();
}
}
}
//CloseServer();
}
catch (Exception e) { Console.WriteLine(e); }
Console.WriteLine("ending handle client");
}
private static void CloseServer()
{
reader.Close();
writer.Close();
clients.ForEach(tcpClient => tcpClient.client.Close());
}
}
}
Client information class:
using System.Net.Sockets;
using System.IO;
namespace Server
{
class Client
{
public TcpClient client;
public StreamWriter writer;
public string clientName;
public Client(TcpClient client, string clientName)
{
this.client = client;
writer = new StreamWriter(client.GetStream());
this.clientName = clientName;
}
}
}
Client application:
using System.Net.Sockets;
using System.Net;
using System.IO;
using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
namespace Client
{
class Program
{
private static TcpClient client = new TcpClient();
private static StreamReader reader;
private static StreamWriter writer;
private static bool refresh;
private static List<string> messages = new List<string>();
public static void Main()
{
Console.Title = "Client";
ConnectLoop();
//Task.WaitAll(sendTask, recieveTask); //wait for end of all tasks
}
private static void ConnectLoop()
{
bool refreshTask = false;
Task sendTask = null, recieveTask = null, updateConvTask = null;
while (true)
{
if(!client.Connected) //try to connect
{
refreshTask = true;
if(sendTask != null || recieveTask != null || updateConvTask != null)
{
sendTask.Dispose();
recieveTask.Dispose();
updateConvTask.Dispose();
sendTask = recieveTask = updateConvTask = null;
}
Console.WriteLine("Connecting to server...");
try
{
client.Connect(IPAddress.Parse("127.0.0.1"), 8080);
}
catch (SocketException) { }
Thread.Sleep(10);
}
else if(refreshTask) // \/ CONNECTED \/
{
Console.WriteLine("Connected.");
reader = new StreamReader(client.GetStream());
writer = new StreamWriter(client.GetStream());
sendTask = Task.Run(() => SendMessage()); //task for sending messages
recieveTask = Task.Run(() => RecieveMessage()); //task for recieving messages
updateConvTask = Task.Run(() => UpdateConversation()); //task for update console window
refreshTask = false;
}
}
}
private static void SendMessage()
{
string msgToSend = string.Empty;
do
{
Console.WriteLine("Enter a message to send to the server");
msgToSend = Console.ReadLine();
writer.WriteLine(msgToSend);
writer.Flush();
} while (!msgToSend.Equals("Exit"));
EndConnection();
}
private static void RecieveMessage()
{
try
{
while (client.Connected)
{
//Console.Clear();
string msg = reader.ReadLine();
if(msg != string.Empty)
{
if (msg == "%C") //special message from server, clear messages if recieve it
{
messages.Clear();
}
else
{
messages.Add(msg);
refresh = true; //refresh console window
}
}
//Console.Clear();
//Console.WriteLine(msgFromServer);
}
}
catch (Exception e)
{
Console.WriteLine(e);
}
}
private static void UpdateConversation()
{
//string conversationTmp = string.Empty;
try
{
while (true)
{
if (refresh) //only if refresh
{
refresh = false;
Console.Clear();
messages.ForEach(msg => Console.WriteLine(msg)); //write all messages
Console.WriteLine();
}
}
}
catch (Exception) { }
}
private static void EndConnection()
{
reader.Close();
writer.Close();
client.Close();
}
}
}
I know that my bug will be something stupid. I'm new to TCP/IP applications, could you give me links to some tutorials that use it and Tasks?
Thanks for any help.
