Ответ 1
... потому что вы так решительны, я собрал очень простой пример того, как писать эхо-сервер, чтобы вы были на вашем пути. Все полученное возвращается обратно клиенту. Сервер будет работать в течение 60 секунд. Попробуйте подключиться к нему на localhost port 6666. Найдите время, чтобы точно понять, что происходит здесь.
void Main()
{
CancellationTokenSource cts = new CancellationTokenSource();
TcpListener listener = new TcpListener(IPAddress.Any, 6666);
try
{
listener.Start();
//just fire and forget. We break from the "forgotten" async loops
//in AcceptClientsAsync using a CancellationToken from `cts`
AcceptClientsAsync(listener, cts.Token);
Thread.Sleep(60000); //block here to hold open the server
}
finally
{
cts.Cancel();
listener.Stop();
}
}
async Task AcceptClientsAsync(TcpListener listener, CancellationToken ct)
{
var clientCounter = 0;
while (!ct.IsCancellationRequested)
{
TcpClient client = await listener.AcceptTcpClientAsync()
.ConfigureAwait(false);
clientCounter++;
//once again, just fire and forget, and use the CancellationToken
//to signal to the "forgotten" async invocation.
EchoAsync(client, clientCounter, ct);
}
}
async Task EchoAsync(TcpClient client,
int clientIndex,
CancellationToken ct)
{
Console.WriteLine("New client ({0}) connected", clientIndex);
using (client)
{
var buf = new byte[4096];
var stream = client.GetStream();
while (!ct.IsCancellationRequested)
{
//under some circumstances, it not possible to detect
//a client disconnecting if there no data being sent
//so it a good idea to give them a timeout to ensure that
//we clean them up.
var timeoutTask = Task.Delay(TimeSpan.FromSeconds(15));
var amountReadTask = stream.ReadAsync(buf, 0, buf.Length, ct);
var completedTask = await Task.WhenAny(timeoutTask, amountReadTask)
.ConfigureAwait(false);
if (completedTask == timeoutTask)
{
var msg = Encoding.ASCII.GetBytes("Client timed out");
await stream.WriteAsync(msg, 0, msg.Length);
break;
}
//now we know that the amountTask is complete so
//we can ask for its Result without blocking
var amountRead = amountReadTask.Result;
if (amountRead == 0) break; //end of stream.
await stream.WriteAsync(buf, 0, amountRead, ct)
.ConfigureAwait(false);
}
}
Console.WriteLine("Client ({0}) disconnected", clientIndex);
}