public async Task <bool> DoLongPollingAsync(
string url, int delay, int timeout)
{
// handle timeout via CancellationTokenSource
using (var cts = new CancellationTokenSource(timeout))
using (var httpClient = new System.Net.Http.HttpClient())
using (cts.Token.Register(() => httpClient.CancelPendingRequests()))
{
try
{
while (true)
{
// do the polling iteration
var data = await httpClient.GetStringAsync(url).ConfigureAwait(false);
if (data == "END POLLING") // should we end polling?
{
return(true);
}
// pause before the next polling iteration
await Task.Delay(delay, cts.Token);
}
}
catch (OperationCanceledException)
{
// is cancelled due to timeout?
if (!cts.IsCancellationRequested)
{
throw;
}
}
// timed out
throw new TimeoutException();
}
}