private async Task DisconnectInternalAsync()
{
var cts = _cancellationTokenSource;
if (cts == null || cts.IsCancellationRequested)
{
return;
}
cts.Cancel(false);
cts.Dispose();
_cancellationTokenSource = null;
try
{
await _adapter.DisconnectAsync(_options.DefaultCommunicationTimeout).ConfigureAwait(false);
MqttNetTrace.Information(nameof(MqttClient), "Disconnected from adapter.");
}
catch (Exception exception)
{
MqttNetTrace.Warning(nameof(MqttClient), exception, "Error while disconnecting from adapter.");
}
finally
{
Disconnected?.Invoke(this, EventArgs.Empty);
}
}
public async Task SendPacketsAsync(TimeSpan timeout, CancellationToken cancellationToken, IEnumerable <MqttBasePacket> packets)
{
await _semaphore.WaitAsync(cancellationToken);
try
{
foreach (var packet in packets)
{
if (packet == null)
{
continue;
}
MqttNetTrace.Information(nameof(MqttChannelCommunicationAdapter), "TX >>> {0} [Timeout={1}]", packet, timeout);
var writeBuffer = PacketSerializer.Serialize(packet);
await _channel.SendStream.WriteAsync(writeBuffer, 0, writeBuffer.Length, cancellationToken).ConfigureAwait(false);
}
if (timeout > TimeSpan.Zero)
{
await _channel.SendStream.FlushAsync(cancellationToken).TimeoutAfter(timeout).ConfigureAwait(false);
}
else
{
await _channel.SendStream.FlushAsync(cancellationToken).ConfigureAwait(false);
}
}
catch (TaskCanceledException)
{
throw;
}
catch (OperationCanceledException)
{
throw;
}
catch (MqttCommunicationTimedOutException)
{
throw;
}
catch (MqttCommunicationException)
{
throw;
}
catch (Exception exception)
{
throw new MqttCommunicationException(exception);
}
finally
{
_semaphore.Release();
}
}
public async Task <MqttBasePacket> ReceivePacketAsync(TimeSpan timeout, CancellationToken cancellationToken)
{
try
{
ReceivedMqttPacket receivedMqttPacket;
if (timeout > TimeSpan.Zero)
{
receivedMqttPacket = await ReceiveAsync(_channel.RawReceiveStream, cancellationToken).TimeoutAfter(timeout).ConfigureAwait(false);
}
else
{
receivedMqttPacket = await ReceiveAsync(_channel.ReceiveStream, cancellationToken).ConfigureAwait(false);
}
if (cancellationToken.IsCancellationRequested)
{
throw new TaskCanceledException();
}
var packet = PacketSerializer.Deserialize(receivedMqttPacket);
if (packet == null)
{
throw new MqttProtocolViolationException("Received malformed packet.");
}
MqttNetTrace.Information(nameof(MqttChannelCommunicationAdapter), "RX <<< {0}", packet);
return(packet);
}
catch (TaskCanceledException)
{
throw;
}
catch (OperationCanceledException)
{
throw;
}
catch (MqttCommunicationTimedOutException)
{
throw;
}
catch (MqttCommunicationException)
{
throw;
}
catch (Exception exception)
{
throw new MqttCommunicationException(exception);
}
}
public void Stop()
{
if (_willMessage != null)
{
_mqttClientSessionsManager.DispatchPublishPacket(this, _willMessage.ToPublishPacket());
}
_cancellationTokenSource?.Cancel(false);
_cancellationTokenSource?.Dispose();
_cancellationTokenSource = null;
_adapter = null;
MqttNetTrace.Information(nameof(MqttClientSession), "Client '{0}': Disconnected.", ClientId);
}
public async Task StopAsync()
{
_cancellationTokenSource?.Cancel(false);
_cancellationTokenSource?.Dispose();
_cancellationTokenSource = null;
foreach (var adapter in _adapters)
{
adapter.ClientAccepted -= OnClientAccepted;
await adapter.StopAsync();
}
_clientSessionsManager.Clear();
MqttNetTrace.Information(nameof(MqttServer), "Stopped.");
}
private async Task ReceivePackets(CancellationToken cancellationToken)
{
MqttNetTrace.Information(nameof(MqttClient), "Start receiving packets.");
try
{
while (!cancellationToken.IsCancellationRequested)
{
_isReceivingPackets = true;
var packet = await _adapter.ReceivePacketAsync(TimeSpan.Zero, cancellationToken).ConfigureAwait(false);
if (cancellationToken.IsCancellationRequested)
{
return;
}
StartProcessReceivedPacket(packet, cancellationToken);
}
}
catch (OperationCanceledException)
{
}
catch (MqttCommunicationException exception)
{
if (cancellationToken.IsCancellationRequested)
{
return;
}
MqttNetTrace.Warning(nameof(MqttClient), exception, "MQTT communication exception while receiving packets.");
await DisconnectInternalAsync().ConfigureAwait(false);
}
catch (Exception exception)
{
MqttNetTrace.Error(nameof(MqttClient), exception, "Unhandled exception while receiving packets.");
await DisconnectInternalAsync().ConfigureAwait(false);
}
finally
{
MqttNetTrace.Information(nameof(MqttClient), "Stopped receiving packets.");
}
}
public async Task StartAsync()
{
if (_cancellationTokenSource != null)
{
throw new InvalidOperationException("The MQTT server is already started.");
}
_cancellationTokenSource = new CancellationTokenSource();
await _clientSessionsManager.RetainedMessagesManager.LoadMessagesAsync();
foreach (var adapter in _adapters)
{
adapter.ClientAccepted += OnClientAccepted;
await adapter.StartAsync(_options);
}
MqttNetTrace.Information(nameof(MqttServer), "Started.");
}
private async Task SendKeepAliveMessagesAsync(CancellationToken cancellationToken)
{
MqttNetTrace.Information(nameof(MqttClient), "Start sending keep alive packets.");
try
{
while (!cancellationToken.IsCancellationRequested)
{
await Task.Delay(_options.KeepAlivePeriod, cancellationToken).ConfigureAwait(false);
if (cancellationToken.IsCancellationRequested)
{
return;
}
await SendAndReceiveAsync <MqttPingRespPacket>(new MqttPingReqPacket()).ConfigureAwait(false);
}
}
catch (OperationCanceledException)
{
}
catch (MqttCommunicationException exception)
{
if (cancellationToken.IsCancellationRequested)
{
return;
}
MqttNetTrace.Warning(nameof(MqttClient), exception, "MQTT communication exception while sending/receiving keep alive packets.");
await DisconnectInternalAsync().ConfigureAwait(false);
}
catch (Exception exception)
{
MqttNetTrace.Warning(nameof(MqttClient), exception, "Unhandled exception while sending/receiving keep alive packets.");
await DisconnectInternalAsync().ConfigureAwait(false);
}
finally
{
MqttNetTrace.Information(nameof(MqttClient), "Stopped sending keep alive packets.");
}
}
private async Task ProcessReceivedPacketAsync(MqttBasePacket packet)
{
try
{
MqttNetTrace.Information(nameof(MqttClient), "Received <<< {0}", packet);
if (packet is MqttPingReqPacket)
{
await SendAsync(new MqttPingRespPacket());
return;
}
if (packet is MqttDisconnectPacket)
{
await DisconnectAsync();
return;
}
if (packet is MqttPublishPacket publishPacket)
{
await ProcessReceivedPublishPacket(publishPacket);
return;
}
if (packet is MqttPubRelPacket pubRelPacket)
{
await ProcessReceivedPubRelPacket(pubRelPacket);
return;
}
_packetDispatcher.Dispatch(packet);
}
catch (Exception exception)
{
MqttNetTrace.Error(nameof(MqttClient), exception, "Unhandled exception while processing received packet.");
}
}
public async Task HandleMessageAsync(string clientId, MqttPublishPacket publishPacket)
{
if (publishPacket == null)
{
throw new ArgumentNullException(nameof(publishPacket));
}
List <MqttPublishPacket> allRetainedMessages;
lock (_retainedMessages)
{
if (publishPacket.Payload?.Any() == false)
{
_retainedMessages.Remove(publishPacket.Topic);
MqttNetTrace.Information(nameof(MqttClientRetainedMessagesManager), "Client '{0}' cleared retained message for topic '{1}'.", clientId, publishPacket.Topic);
}
else
{
_retainedMessages[publishPacket.Topic] = publishPacket;
MqttNetTrace.Information(nameof(MqttClientRetainedMessagesManager), "Client '{0}' updated retained message for topic '{1}'.", clientId, publishPacket.Topic);
}
allRetainedMessages = new List <MqttPublishPacket>(_retainedMessages.Values);
}
try
{
// ReSharper disable once UseNullPropagation
if (_options.Storage != null)
{
await _options.Storage.SaveRetainedMessagesAsync(allRetainedMessages.Select(p => p.ToApplicationMessage()).ToList());
}
}
catch (Exception exception)
{
MqttNetTrace.Error(nameof(MqttClientRetainedMessagesManager), exception, "Unhandled exception while saving retained messages.");
}
}
private void OnClientDisconnected(object sender, MqttClientDisconnectedEventArgs eventArgs)
{
MqttNetTrace.Information(nameof(MqttServer), "Client '{0}': Disconnected.", eventArgs.Client.ClientId);
ClientDisconnected?.Invoke(this, eventArgs);
}