private void _ClientReadLine(ConnectedEndPoint readClient, string text)
{
_OnStatus($"Client {readClient.RemoteEndPoint}: \"{text}\"");
lock (_lock)
{
if (_closing)
{
return;
}
text = $"{readClient.RemoteEndPoint}: {text}";
foreach (ConnectedEndPoint client in _clients.Where(c => c != readClient))
{
try
{
client.WriteLine(text);
}
catch (IOException e)
{
_OnClientException(client, e.Message);
}
}
}
}
// Top-level "clean-up" method, which will observe and report all exceptions
// In real-world code, would probably want to simply log any unexpected exceptions
// to a log file and then exit the process. Here, we just exit after reporting
// exception info to caller. In either case, there's no need to observe a Task from
// this method, and async void simplifies the call (no need to receive and then ignore
// the Task object just to keep the compiler quiet).
private async void _CleanupClientAsync(ConnectedEndPoint client)
{
try
{
await client.ReadTask;
}
catch (IOException e)
{
_OnClientException(client, e.Message);
}
catch (Exception e)
{
// Unexpected exceptions are programmer-error. They could be anything, and leave
// the program in an unknown, possibly corrupt state. The only reasonable disposition
// is to log, then exit.
//
// Full stack-trace, because who knows what this exception was. Will need the
// stack-trace to do any diagnostic work.
_OnStatus($"Unexpected client connection exception. {e}");
Environment.Exit(1);
}
finally
{
_RemoveClient(client);
client.Dispose();
}
}
private static void _StartUserInput(ConnectedEndPoint server)
{
// Get user input in a new thread, so main thread can handle waiting
// on connection.
new Thread(() =>
{
try
{
string line;
while ((line = ReadLine()) != "")
{
server.WriteLine(line);
}
server.Shutdown();
}
catch (IOException e)
{
WriteLine($"Server {server.RemoteEndPoint} IOException: {e.Message}");
}
catch (Exception e)
{
WriteLine($"Unexpected server exception: {e}");
Environment.Exit(1);
}
})
{
// Setting IsBackground means this thread won't keep the
// process alive. So, if the connection is closed by the server,
// the main thread can exit and the process as a whole will still
// be able to exit.
IsBackground = true
}.Start();
}
private void _RemoveClient(ConnectedEndPoint client)
{
lock (_lock)
{
_clients.Remove(client);
_OnStatus($"removed client {client.RemoteEndPoint} -- {_clients.Count} clients connected");
}
}
private void _AddClient(ConnectedEndPoint client)
{
lock (_lock)
{
_clients.Add(client);
_OnStatus($"added client {client.RemoteEndPoint} -- {_clients.Count} clients connected");
}
}
static void Main(string[] args)
{
IPEndPoint remoteEndPoint = new IPEndPoint(IPAddress.Loopback, _kportNumber);
ConnectedEndPoint server = ConnectedEndPoint.Connect(remoteEndPoint, (c, s) => WriteLine(s));
_StartUserInput(server);
_SafeWaitOnServerRead(server).Wait();
}
private static async Task _SafeWaitOnServerRead(ConnectedEndPoint server)
{
try
{
await server.ReadTask;
}
catch (IOException e)
{
WriteLine($"Server {server.RemoteEndPoint} IOException: {e.Message}");
}
catch (Exception e)
{
// Should never happen. It's a bug in this code if it does.
WriteLine($"Unexpected server exception: {e}");
}
}
private async Task _ListenAsync()
{
try
{
while (true)
{
ConnectedEndPoint client = await ConnectedEndPoint.AcceptAsync(_listener, _ClientReadLine);
_AddClient(client);
_CleanupClientAsync(client);
}
}
catch (ObjectDisposedException)
{
_OnStatus("Server's listening socket closed");
}
catch (IOException e)
{
_OnStatus($"Listening socket IOException: {e.Message}");
}
await _CleanupServerAsync();
}
private void _OnClientException(ConnectedEndPoint client, string message)
{
_OnStatus($"Client {client.RemoteEndPoint} IOException: {message}");
}