internal void UnexpectedTermination(Exception exception)
{
TerminateAsync();
OngoingInitialisation = false;
var secondsOfActiveConnection = (DateTime.Now - (_currentConnectionStarted ?? DateTime.Now)).TotalSeconds;
Debug.WriteLine($"Event Listener terminated unexpectedly after {secondsOfActiveConnection} seconds.");
if (AutoReconnect)
{
Debug.WriteLine($"{exception.GetType()} occured.");
if (_firstReconnectAttempt == null)
{
_firstReconnectAttempt = DateTime.Now;
}
if (((DateTime)_firstReconnectAttempt).AddMinutes(1) < DateTime.Now)
{
_abortionRequested = false;
_attempts = 0;
_firstReconnectAttempt = null;
Debug.WriteLine("Attempting to reconnect...");
AttemptedReconnect?.Invoke(this, new AttemptedReconnectEvent(_attempts));
InitializeAsync();
}
else //recently attempted to reconnect
{
_attempts++;
Debug.WriteLine($"Attempting to reconnect... {_attempts}");
AttemptedReconnect?.Invoke(this, new AttemptedReconnectEvent(_attempts));
if (_attempts >= 3)
{
_abortionRequested = true;
_attempts = 0;
_firstReconnectAttempt = null;
Debug.WriteLine($"Too many reconnection attempts ({_attempts})");
Debug.WriteLine($"Event subscription will be terminated. ({_attempts})");
TerminatedUnexpectedly?.Invoke(this, new TerminatedUnexpectedlyEvent(exception));
Debug.WriteLine("New initialisation required.");
}
else
{
InitializeAsync();
}
}
}
else
{
Debug.WriteLine($"Event subscription will be terminated. ({_attempts})");
TerminatedUnexpectedly?.Invoke(this, new TerminatedUnexpectedlyEvent(exception));
AutoReconnect = false;
Debug.WriteLine("New initialisation required.");
}
}
/// <summary>
/// Initializes an asynchronous Rest prompt which is read and interpreted.
/// Results can be aquired by listening to the relevant event
/// </summary>
public async void InitializeAsync(bool autoreconnect = true)
{
_abortionRequested = false;
AutoReconnect = autoreconnect;
if (IsInitialized || OngoingInitialisation)
{
return;
}
OngoingInitialisation = true;
_currentConnectionStarted = null;
Debug.WriteLine("Initialize Event Listener...");
await Task.Run(() =>
{
// asynchronous stream reader
using (var httpClient = new HttpClient())
{
httpClient.Timeout = TimeSpan.FromMilliseconds(Timeout.Infinite);
var requestUri = $"{OpenHab.RestClient.Url}/events";
try
{
var stream = httpClient.GetStreamAsync(requestUri).Result;
using (var reader = new StreamReader(stream))
{
IsInitialized = true;
AttemptedReconnect?.Invoke(this, new AttemptedReconnectEvent(-1));
Debug.WriteLine("Event Listener initialized.");
_currentConnectionStarted = DateTime.Now;
var dataTemplate = new Regex(@"data:\s({.*})");
while (!_abortionRequested)
{
try
{
if (reader.EndOfStream)
{
TerminateAsync();
break;
}
}
catch (Exception e)
{
UnexpectedTermination(e);
break;
}
if (_abortionRequested)
{
break;
}
var currentLine = reader.ReadLine();
if (currentLine == null)
{
continue;
}
var data = dataTemplate.Match(currentLine).Groups[1];
if (!data.Success)
{
continue;
}
RaiseEvent(data.Value);
}
}
}
catch (AggregateException e)
{
UnexpectedTermination(e);
}
}
if (_currentConnectionStarted == null)
{
return;
}
var secondsOfActiveConnection = (DateTime.Now - _currentConnectionStarted.Value).TotalSeconds;
Debug.WriteLine($"Event Listener terminated after {secondsOfActiveConnection} seconds.");
});
}
