async Task <IEnumerable <DiscoveryDevice> > Discover(int timeout, IOnvifUdpClient client,
CancellationToken cancellationToken = default)
{
Guid messageId = Guid.NewGuid();
var responses = new List <UdpReceiveResult> ();
var cts = new CancellationTokenSource(TimeSpan.FromSeconds(timeout));
try {
await SendProbe(client, messageId);
while (true)
{
if (cts.IsCancellationRequested || cancellationToken.IsCancellationRequested)
{
break;
}
var response = await client.ReceiveAsync().WithCancellation(cancellationToken).WithCancellation(cts.Token);
if (!IsAlreadyDiscovered(response, responses))
{
responses.Add(response);
}
}
} catch (OperationCanceledException) {
// Either the user canceled the action or the timeout has fired
} finally {
client.Close();
}
if (cancellationToken.IsCancellationRequested)
{
return(new List <DiscoveryDevice> ());
}
return(ProcessResponses(responses, messageId));
}
async Task Discover(int timeout, IOnvifUdpClient client,
Action <DiscoveryDevice> onDeviceDiscovered,
CancellationToken cancellationToken = default)
{
Guid messageId = Guid.NewGuid();
var responses = new List <UdpReceiveResult> ();
var cts = new CancellationTokenSource(TimeSpan.FromSeconds(timeout));
try {
await SendProbe(client, messageId);
while (true)
{
if (cts.IsCancellationRequested || cancellationToken.IsCancellationRequested)
{
break;
}
try {
var response = await client.ReceiveAsync()
.WithCancellation(cancellationToken)
.WithCancellation(cts.Token);
if (IsAlreadyDiscovered(response, responses))
{
continue;
}
responses.Add(response);
var discoveredDevice = ProcessResponse(response, messageId);
if (discoveredDevice != null)
{
#pragma warning disable 4014 // Just trigger the callback and forget about it. This is expected to avoid locking the loop
Task.Run(() => onDeviceDiscovered(discoveredDevice));
#pragma warning restore 4014
}
} catch (OperationCanceledException) {
// Either the user canceled the action or the timeout has fired
} catch (Exception) {
// we catch all exceptions !
// Something might be bad in the response of a camera when call ReceiveAsync (BeginReceive in socket) fail
}
}
} finally {
client.Close();
}
}