How to set a timeout value on StreamSocket's ConnectAsync()?

Question

In the Windows Phone 8.1 app I had to create my socket as follows. How can I change it so that it will timeout after a period that I can specify?

_socket = new StreamSocket();
await _socket.ConnectAsync(hostName, port.ToString(), SocketProtectionLevel.PlainSocket);

await _socket.InputStream.ReadAsync(frameLenData, frameLenData.Capacity, Windows.Storage.Streams.InputStreamOptions.None);

In my pre- Windows Phone code I'd create the Socket and set the timeout by testing _event.WaitOne(timeout), e.g.

timeout = 5000;
_event = new ManualResetEvent(false);
_socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

bool bOperationFailed = false;
SocketAsyncEventArgs socketEventArg = new SocketAsyncEventArgs();
socketEventArg.RemoteEndPoint = new DnsEndPoint(address, port);


_event.Reset();

_socket.ReceiveAsync(socketEventArg);

// Wait for completion
if (_event.WaitOne(timeout) == false)
{
    Trace.trace("timed out");
    return false;
}

Can I set the timeout period for StreamSocket's ConnectAsync()? If so, how?

score 8 · Accepted Answer · answered Aug 26 '14 at 08:01

8

Use a CancellationTokenSource and AsTask extension method.

var cts = new CancellationTokenSource();
cts.CancelAfter(2000); // cancel after 2 seconds

var connectAsync = _socket.ConnectAsync( ... );
var connectTask = connectAsync.AsTask(cts.Token);

await connectTask;

answered Aug 26 '14 at 08:01

esskar

10,638
3
36
57

cool - would this work with `await _socket.InputStream.ReadAsync` also? – DaveDev Aug 26 '14 at 08:10
i would think so. Everything that is a 'IAsyncAction` can be converted to a task [1]. But make sure you create a new `CancellationTokenSource`. [1]: http://msdn.microsoft.com/en-us/library/hh779334(v=vs.110).aspx – esskar Aug 26 '14 at 08:17

score 2 · Answer 2 · answered Sep 16 '16 at 14:05

2

Since I do not have the reputation to add a comment I have to put it another answer.

Another way that doesn't require extra variables if they aren't required:

await socket.ConnectAsync(hostName, port).AsTask(new CancellationTokenSource(TimeSpan.FromSeconds(2)).Token);

answered Sep 16 '16 at 14:05

Michael Woolsey

803
8
15

this does not work, the AsTask method does not exist (at least not in .NET Core 3.0) method from @Chris Ruck works. – shelbypereira Jan 28 '20 at 06:53

score 1 · Answer 3 · answered Dec 19 '17 at 10:15

1

I do the following, which seems to work for me:

if (!_socket.ConnectAsync(uri, CancellationToken.None).Wait(timeout))
{
    // connect timed out
}

answered Dec 19 '17 at 10:15

Chris Ruck

391
3
4

2

the issue with this approach is that it is blocking, and you use the asnyc /await benefits, I would suggest something like (SEE: https://stackoverflow.com/questions/4238345/asynchronously-wait-for-taskt-to-complete-with-timeout): int timeout = 1000; var task = SomeOperationAsync(); if (await Task.WhenAny(task, Task.Delay(timeout)) == task) { // task completed within timeout } else { // timeout logic } – shelbypereira Jan 28 '20 at 07:34

score 0 · Answer 4 · answered Mar 17 '22 at 23:18

I tried using esskar's answer/solution but it didn't work since, as has been previously mentioned, the AsTask() method doesn't exist in latest version of .Net that I'm using.

So, I tweaked the solution just a tad to do the following, please check my work to see if this meets the requirements:

using (var sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
{
      var timeout = 1000;
      var cts = new CancellationTokenSource();
      cts.CancelAfter(timeout);

      var connectAsync = sock.ConnectAsync(address, port, cts.Token); // address and port set earlier in scope
      await connectAsync;          
}

How to set a timeout value on StreamSocket's ConnectAsync()?

4 Answers4

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