static void Main(string[] args)
{
// Display logo
ChatShell();
TcpListener listner = null;
// The server will be listening to the below port for client connections
int port = 6969;
try
{
// Listen for client connections on any ip address on above declared port
listner = new TcpListener(IPAddress.Any, port);
listner.Start();
Console.WriteLine("ChatShell server started.");
Console.WriteLine("Awaiting clients...");
// Run on an infinite loop
while (true)
{
if (listner.Pending())
{
TcpClient client = default(TcpClient);
client = listner.AcceptTcpClient();
// Get username from client as a byte array and then encode to ASCII string;
byte[] inStream = new byte[100];
NetworkStream networkStream = client.GetStream();
int bytesRead = networkStream.Read(inStream, 0, inStream.Length);
string recievedData = Encoding.ASCII.GetString(inStream, 0, bytesRead);
//Decrypt data gotten from client
recievedData = encryptor.decrypt(recievedData);
//Get connection password and username (stored in client data)
string pass = recievedData.Substring(0, 4);
string clientData = recievedData.Remove(0, 4);
//If invalid connection password block user and send error message
if (!pass.Equals("PASS"))
{
Console.ForegroundColor = ConsoleColor.Yellow;
Console.WriteLine($"Forceful connection declined!");
Console.ForegroundColor = ConsoleColor.White;
// Send an encoded and encrypted message to the client saying that the username alredy exists
byte[] outStream = Encoding.ASCII.GetBytes("Invalid client. Please use ChatShell to connect");
networkStream.Write(outStream, 0, outStream.Length);
}
// If user with the same username exists
else if (clients.ContainsKey(clientData))
{
Console.ForegroundColor = ConsoleColor.Yellow;
Console.WriteLine($"User with username {clientData} tried to connect. But was rejected as that username already exists");
Console.ForegroundColor = ConsoleColor.White;
// Send an encoded and encrypted message to the client saying that the username alredy exists
byte[] outStream = Encoding.ASCII.GetBytes(encryptor.encrypt("!error user-exists"));
networkStream.Write(outStream, 0, outStream.Length);
}
else
{
// Send a message to the client allowing the connection after encryption. Encrypted message is turned into a bye array when sending
byte[] outStream = Encoding.ASCII.GetBytes(encryptor.encrypt("!connect"));
networkStream.Write(outStream, 0, outStream.Length);
//Prevent network stream messages from overlapping
Thread.Sleep(10);
//Display message in server CLI
Console.BackgroundColor = ConsoleColor.DarkGreen;
Console.ForegroundColor = ConsoleColor.White;
Console.WriteLine($"{clientData} connected to the chat");
Console.BackgroundColor = ConsoleColor.Black;
//Broadcast message to other clients
broadcastMessage($"!rc {clientData} connected to the chat", clientData, false);
//Add new client to client list;
clients.Add(clientData, client);
// Send already connected user list to clients
if (clients.Count != 0)
{
broadcastMessage(getUserList(), clientData, false);
}
//Create ClientClass object and set variable values
ClientClass clientObject = new ClientClass();
clientObject.username = clientData;
clientObject.client = client;
//Create new thread to handle client
Thread thread = new Thread(handleClient);
thread.Start(clientObject);
}
}
}
}catch (Exception e)
{
Console.WriteLine(e.Message);
}
Console.ReadKey();
}
// Method to handle a single client (will run on multiple threads for different clients)
static void handleClient(object clientObject)
{
// Cast the recieved ClientClass object
ClientClass recievedClientObject = (ClientClass)clientObject;
// Get the TcpClient object and username from the ClientClass object
TcpClient client = recievedClientObject.client;
string username = recievedClientObject.username;
try
{
string dataFromClient = null;
// Until client sends a disconnecting command run this loop
do
{
// Recive data from the client using the network stream
byte[] inStream = new byte[4096];
NetworkStream networkStream = client.GetStream();
int bytesRead = networkStream.Read(inStream, 0, inStream.Length);
dataFromClient = Encoding.ASCII.GetString(inStream, 0, bytesRead);
// Decrypt the data taken from client
dataFromClient = encryptor.decrypt(dataFromClient);
// If the client doesnt send a disconnect command
if (!dataFromClient.Equals("!exit"))
{
// If the client wants to send a private message to another client
if (dataFromClient.StartsWith("!pm"))
{
Console.WriteLine($"{dataFromClient}");
broadcastPrivateMessage(dataFromClient);
}
//If the client message is public
else
{
Console.WriteLine($"{username}: {dataFromClient}");
broadcastMessage(dataFromClient, username, true);
}
}
// Exit loop after client sends disconnect command
} while (!(dataFromClient.Equals("!exit") || dataFromClient == null));
// After the client had disconnected
// Remove the client from the hashtable
clients.Remove(username);
// Display message on server
Console.BackgroundColor = ConsoleColor.Red;
Console.ForegroundColor = ConsoleColor.White;
Console.WriteLine($"{username} disconnected from the chat");
Console.BackgroundColor = ConsoleColor.Black;
// Broadcast to other clients in an encoded message that the client has disconnected
broadcastMessage($"!dc {username} disconnected from the chat", username, false);
// Send updated user list to clients if there are connected clients
if (clients.Count != 0)
{
broadcastMessage(getUserList(), username, false);
}
}
catch (IOException e)
{
Console.WriteLine(e.Message);
}
finally
{
// Finally close the created TcpClient object
if (client != null)
{
client.Close();
}
}
}
