/// <summary>
/// Alg 4.
/// </summary>
/// <param name="client">Instance clienta</param>
/// <param name="version">Domluvena verze</param>
private async void HandleMessages( TcpClient client, int version ) {
var networkStream = client.GetStream();
var cancelClient = new CancellationTokenSource();
try {
while( true ) {
//Vytvoreni tasku pro odpojeni clienta, pokud 180sec neposle ping
if( version > 0 )
#pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
Task.Run( () => Task.Delay( 180000, cancelClient.Token ).
ContinueWith( ( x ) => DisconnectClient( client ), cancelClient.Token ) );
#pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
//Task pro prijmuti zpravy od clienta
byte[] buffer = new byte[ 4096 ];
int bufferSize = await networkStream.ReadAsync( buffer, 0, buffer.Length );
Message msg = Message.ParseMsgFromBytes( buffer, bufferSize );
//Prisla zprava typu Msg, tak ji preposlu vsem clientum
if( msg.MsgType == Msg.MSG ) {
byte[] toBroadcast = msg.ToByteArray();
foreach( var other in Clients ) {
if(other.Connected)
await other.GetStream().WriteAsync( toBroadcast, 0, toBroadcast.Length );
}
}
//Prisla zprava typu Ping, takze zrusim predchozi task na pingovani a vytvorim novy pro dalsich 180sec
//a jeste odeslu clientovi pong
if(version > 0 && msg.MsgType == Msg.PING ) {
cancelClient.Cancel();
cancelClient = new CancellationTokenSource();
var pong = new Message( Msg.PONG, DateTime.Now, 1 ).ToByteArray();
await networkStream.WriteAsync( pong, 0, pong.Length );
#pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
Task.Run( () => Task.Delay( 180000, cancelClient.Token ).
ContinueWith( ( x ) => DisconnectClient( client ), cancelClient.Token ) );
#pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
}
}
}
catch( ObjectDisposedException ) {
window.AddTextLine( "Error Server: HandleMessages() ObjectDisposedException" );
this.Stop();
return;
}
catch( System.IO.IOException ) {
window.AddTextLine( "Error Server: HandleMessages() IOException" );
this.Stop();
return;
}
catch( Exception e ) {
System.Windows.MessageBox.Show( "Unknown Server error: " + e.Message );
this.Stop();
return;
}
}
/// <summary>
/// Alg 3.
/// </summary>
/// <param name="client">Instance clienta</param>
/// <returns></returns>
private async Task<int> SendHandshake( TcpClient client ) {
var networkStream = client.GetStream();
byte[] buffer = new byte[ 4096 ];
//WAITING FOR HELLO
int bufferSize = await networkStream.ReadAsync( buffer, 0, buffer.Length );
var helloMsg = Message.ParseMsgFromBytes( buffer, bufferSize );
if(helloMsg.MsgType != Msg.HELLO ) //Pokud prislo neco jinyho nez hello, tak odpojim clienta (zpatny pro DDOS)
DisconnectClient( client );
string[] bodySplits = helloMsg.Body.Split( ' ' );
string latestVersion = bodySplits[ bodySplits.Length - 1 ];
int intVersion = latestVersion == "1.1" ? 1 : 0;
//ACCEPTED HELLO, SENDING OLLEH
var ollehBytes = new Message( Msg.OLLEH, DateTime.Now, intVersion ).ToByteArray();
await networkStream.WriteAsync( ollehBytes, 0, ollehBytes.Length );
//OLLEH SENT, WAITING FOR ACK
bufferSize = await networkStream.ReadAsync( buffer, 0, buffer.Length );
var ackMsg = Message.ParseMsgFromBytes( buffer, bufferSize );
if( ackMsg.MsgType != Msg.ACK ) //Pokud prislo neco jinyho nez ack, tak odpojim clienta (zpatny protokol)
DisconnectClient( client );
//ACCEPTED ACK
return intVersion;
}
/// <summary>
/// Alg 4.
/// </summary>
/// <param name="username"></param>
/// <returns></returns>
private async Task InitializeConnection( string username ) {
byte[] buffer = new byte[ 4096 ];
//SENDING HELLO
var hello = new Message( Msg.HELLO, DateTime.Now, 1 );
var helloBytes = hello.ToByteArray();
await stream.WriteAsync( helloBytes, 0, helloBytes.Length );
//WAITING FOR OLLEH
int bufferSize = await stream.ReadAsync( buffer, 0, buffer.Length );
var olleh = Message.ParseMsgFromBytes( buffer, bufferSize );
if( olleh.MsgType != Msg.OLLEH )
throw new Exception( "Got something else than OLLEH packet" );
//ACCEPTED OLLEH, SENDING ACK
var ackBytes = new Message( Msg.ACK, DateTime.Now, 1 ).ToByteArray();
await stream.WriteAsync( ackBytes, 0, ackBytes.Length );
//CONNECTED
}
/// <summary>
/// Metoda pro odesilani zprav typu "MSG" na server
/// </summary>
/// <param name="message"></param>
public async void SendMessage( string message ) {
if( !client.Connected ) {
System.Windows.MessageBox.Show( "Cannot send messages (not connected)" );
return;
}
var msgBytes = new Message( Msg.MSG, DateTime.Now, 1, message, username ).ToByteArray();
await stream.WriteAsync( msgBytes, 0, msgBytes.Length );
}
/// <summary>
/// Nekonecny task pro posilani pingu po 60sec.
/// Vytvari se s pingCancelation tokenem pro jeho zruseni pri Disconnectu
/// </summary>
private async void SendPing() {
var ping = new Message( Msg.PING, DateTime.Now, 1 ).ToByteArray();
await stream.WriteAsync( ping, 0, ping.Length );
try {
await Task.Delay( 60000 ).ContinueWith( ( x ) => SendPing(), pingCancelation.Token );
}
catch( TaskCanceledException ) {
}
}
