Stop() seems to be hanging

Hi,

I have some trouble managing the channel close on client request. I’m in an ASP.Net Core / .NetCore 5 environment.

I wrote a wrapper as an injected service with Singleton scope around your library which you can find below. This service is called on background using Hangfire.

When I Ctrl+C the console server, I managed to tell the Hangfire job to call the stop method of my websocket service. Stop() fires the exit event, so that the second part of the Listen() method (where it stops) is executed. The end of the Listen() method is reached, but later on, Hangfire throws the exception when a job was not gracefully stopped. I think there is an issue with disposing the client, and / or subscriptions to events.

private WebsocketClient _client;
private ManualResetEvent _exitEvent;
public bool Connected;

public void Start()
{
	// Logging
	var identifier = $"[ {nameof(StandardSocketService)}.{nameof(Start)} ]";
	_logger.LogInformation($"{identifier} Starting connexion to WebSocket {_endpoint}");

	// Connect and listen
	_exitEvent = new ManualResetEvent(false);
	var url = new Uri(_endpoint);

	// callbacks
	_client = new WebsocketClient(url) { ReconnectTimeout = TimeSpan.FromMilliseconds(ReconnexionTimeout) };
	_client.DisconnectionHappened.Subscribe(info =>
	{
		Connected = false;
		_logger.LogInformation($"{identifier} Disconnection happened, type: {info.Type}");
	});
	_client.ReconnectionHappened.Subscribe(info =>
	{
		_logger.LogInformation($"{identifier} Reconnection happened, type: {info.Type}");
	});
	_client.MessageReceived.Subscribe(msg =>
	{
		_logger.LogInformation($"{identifier} Message received: {msg}");
	});
	// Actual start
	_client.Start();
	Connected = true;
	_logger.LogInformation($"{identifier} Started connexion to WebSocket {_endpoint}");
}

public void Listen()
{
	if (!Connected) Start();
	// Logging
	var identifier = $"[ {nameof(StandardSocketService)}.{nameof(Listen)} ]";
	_logger.LogInformation($"{identifier} Listening to WebSocket {_endpoint}");
	_exitEvent.WaitOne(); // block here until receive _exitEvent.Set();

	// We reach here when shutdown of application is required
	_client.IsReconnectionEnabled = false;
	_client.Stop(WebSocketCloseStatus.Empty, string.Empty);
	Connected = false;
	_logger.LogWarning($"{identifier} Closed connexion to WebSocket {_endpoint}");
}

public void Send(string data)
{
	if (!Connected) Listen();
	_client.Send(data);
}

public void Stop() => _exitEvent.Set();

[kall2sollies]

Works like a charm with the AsyncEx nuget package, and the pattern you provided! Thanks for your knowledge!

[kall2sollies]

Thanks a lot for the tips, I’ll dig further about AsyncManualResetEvent. As a pure Web backend developer, dealing with threads is way out of my comfort zone ! And thanks for the Task.Factory.StartNew(), I remembered the Thread.Start() was almost deprecated, but couldn’t remember of the former. Anyway, since then, I gave up the Thread thing for a simple await exactly the same way you mentioned. I’ll just have to replace the infinite loop given your hints.