Merge develop.

Build/MQTTnet.AspNetCore.nuspec

@@ -15,7 +15,7 @@
     <copyright>Copyright Christian Kratky 2016-2018</copyright>
     <tags>MQTT Message Queue Telemetry Transport MQTTClient MQTTServer Server MQTTBroker Broker NETStandard IoT InternetOfThings Messaging Hardware Arduino Sensor Actuator M2M ESP Smart Home Cities Automation Xamarin</tags>
     <dependencies>
-      <dependency id="MQTTnet" version="2.8.3" />
+      <dependency id="MQTTnet" version="2.8.4" />
       <dependency id="Microsoft.AspNetCore.Connections.Abstractions" version="2.1.0" />
       <dependency id="Microsoft.AspNetCore.WebSockets" version="2.0.1" />
       <dependency id="Microsoft.Extensions.Hosting.Abstractions" version="2.0.1" />

Build/MQTTnet.Extensions.ManagedClient.nuspec

@@ -15,7 +15,7 @@
     <copyright>Copyright Christian Kratky 2016-2018</copyright>
     <tags>MQTT Message Queue Telemetry Transport MQTTClient MQTTServer Server MQTTBroker Broker NETStandard IoT InternetOfThings Messaging Hardware Arduino Sensor Actuator M2M ESP Smart Home Cities Automation Xamarin</tags> 
     <dependencies>
-      <dependency id="MQTTnet" version="2.8.3" />
+      <dependency id="MQTTnet" version="2.8.4" />
     </dependencies>
   </metadata>
 

Build/MQTTnet.Extensions.Rpc.nuspec

@@ -15,7 +15,7 @@
     <copyright>Copyright Christian Kratky 2016-2018</copyright>
     <tags>MQTT Message Queue Telemetry Transport MQTTClient MQTTServer Server MQTTBroker Broker NETStandard IoT InternetOfThings Messaging Hardware Arduino Sensor Actuator M2M ESP Smart Home Cities Automation Xamarin</tags> 
     <dependencies>
-      <dependency id="MQTTnet" version="2.8.3" />
+      <dependency id="MQTTnet" version="2.8.4" />
     </dependencies>
   </metadata>
 

Build/MQTTnet.nuspec

@@ -10,10 +10,7 @@
     <iconUrl>https://raw.githubusercontent.com/chkr1011/MQTTnet/master/Images/Logo_128x128.png</iconUrl>
     <requireLicenseAcceptance>false</requireLicenseAcceptance>
     <description>MQTTnet is a high performance .NET library for MQTT based communication. It provides a MQTT client and a MQTT server (broker).</description>
-    <releaseNotes>* [Core] Added all factory methods to the factory interface.
-* [Core] Fixed an issue with cancellation token handling (thanks to @acrabb).
-* [Server] Added a new overload for configuring the ASP.net integration (thanks to @JanEggers).
-* [Server] Added a method for clearing all retained messages.
+    <releaseNotes>* [Client] Fixed a deadlock when an exception is fired while connecting (thanks to @malibVB).
     </releaseNotes>
     <copyright>Copyright Christian Kratky 2016-2018</copyright>
     <tags>MQTT Message Queue Telemetry Transport MQTTClient MQTTServer Server MQTTBroker Broker NETStandard IoT InternetOfThings Messaging Hardware Arduino Sensor Actuator M2M ESP Smart Home Cities Automation Xamarin</tags> 

Source/MQTTnet/Adapter/MqttChannelAdapter.cs

@@ -150,6 +150,9 @@ namespace MQTTnet.Adapter
 
                 return packet;
             }
+            catch (OperationCanceledException)
+            {
+            }
             catch (Exception exception)
             {
                 if (IsWrappedException(exception))
@@ -237,7 +240,8 @@ namespace MQTTnet.Adapter
         {
             if (exception is IOException && exception.InnerException is SocketException socketException)
             {
-                if (socketException.SocketErrorCode == SocketError.ConnectionAborted)
+                if (socketException.SocketErrorCode == SocketError.ConnectionAborted ||
+                    socketException.SocketErrorCode == SocketError.OperationAborted)
                 {
                     throw new OperationCanceledException();
                 }

Source/MQTTnet/Client/MqttClient.cs

@@ -29,7 +29,7 @@ namespace MQTTnet.Client
         internal Task _keepAliveMessageSenderTask;
         private IMqttChannelAdapter _adapter;
         private bool _cleanDisconnectInitiated;
-        private TaskCompletionSource<bool> _disconnectReason;
+        private int _disconnectGate;
 
         public MqttClient(IMqttClientAdapterFactory channelFactory, IMqttNetLogger logger)
         {
@@ -54,12 +54,12 @@ namespace MQTTnet.Client
 
             try
             {
-                _cancellationTokenSource = new CancellationTokenSource();
-                _disconnectReason = new TaskCompletionSource<bool>();
                 _options = options;
                 _packetIdentifierProvider.Reset();
                 _packetDispatcher.Reset();
 
+                _cancellationTokenSource = new CancellationTokenSource();
+                _disconnectGate = 0;
                 _adapter = _adapterFactory.CreateClientAdapter(options, _logger);
 
                 _logger.Verbose($"Trying to connect with server ({_options.ChannelOptions}).");
@@ -87,10 +87,12 @@ namespace MQTTnet.Client
             catch (Exception exception)
             {
                 _logger.Error(exception, "Error while connecting with server.");
-                if (_disconnectReason.TrySetException(exception))
+
+                if (!DisconnectIsPending())
                 {
                     await DisconnectInternalAsync(null, exception).ConfigureAwait(false);
                 }
+
                 throw;
             }
         }
@@ -108,7 +110,7 @@ namespace MQTTnet.Client
             }
             finally
             {
-                if (_disconnectReason.TrySetCanceled())
+                if (!DisconnectIsPending())
                 {
                     await DisconnectInternalAsync(null, null).ConfigureAwait(false);
                 }
@@ -183,7 +185,7 @@ namespace MQTTnet.Client
 
         public void Dispose()
         {
-            _cancellationTokenSource?.Cancel (false);
+            _cancellationTokenSource?.Cancel(false);
             _cancellationTokenSource?.Dispose();
             _cancellationTokenSource = null;
 
@@ -224,9 +226,10 @@ namespace MQTTnet.Client
 
         private async Task DisconnectInternalAsync(Task sender, Exception exception)
         {
-            InitiateDisconnect();
-
             var clientWasConnected = IsConnected;
+
+            InitiateDisconnect();
+            
             IsConnected = false;
 
             try
@@ -247,7 +250,7 @@ namespace MQTTnet.Client
             }
             finally
             {
-                Dispose ();
+                Dispose();
                 _cleanDisconnectInitiated = false;
 
                 _logger.Info("Disconnected.");
@@ -261,16 +264,16 @@ namespace MQTTnet.Client
             {
                 try
                 {
-                    if (_cancellationTokenSource == null || _cancellationTokenSource.IsCancellationRequested)
+                    if (_cancellationTokenSource?.IsCancellationRequested == true)
                     {
                         return;
                     }
 
-                    _cancellationTokenSource.Cancel(false);
+                    _cancellationTokenSource?.Cancel(false);
                 }
-                catch (Exception adapterException)
+                catch (Exception exception)
                 {
-                    _logger.Warning(adapterException, "Error while initiating disconnect.");
+                    _logger.Warning(exception, "Error while initiating disconnect.");
                 }
             }
         }
@@ -358,7 +361,7 @@ namespace MQTTnet.Client
                     _logger.Error(exception, "Unhandled exception while sending/receiving keep alive packets.");
                 }
 
-                if (_disconnectReason.TrySetException(exception))
+                if (!DisconnectIsPending())
                 {
                     await DisconnectInternalAsync(_keepAliveMessageSenderTask, exception).ConfigureAwait(false);
                 }
@@ -377,8 +380,10 @@ namespace MQTTnet.Client
             {
                 while (!cancellationToken.IsCancellationRequested)
                 {
-                    var packet = await _adapter.ReceivePacketAsync(TimeSpan.Zero, cancellationToken).ConfigureAwait(false);
-                    if (packet != null)
+                    var packet = await _adapter.ReceivePacketAsync(TimeSpan.Zero, cancellationToken)
+                        .ConfigureAwait(false);
+
+                    if (packet != null && !cancellationToken.IsCancellationRequested)
                     {
                         await ProcessReceivedPacketAsync(packet, cancellationToken).ConfigureAwait(false);
                     }
@@ -393,7 +398,6 @@ namespace MQTTnet.Client
 
                 if (exception is OperationCanceledException)
                 {
-                    _logger.Verbose ("MQTT OperationCanceled exception while receiving packets.");
                 }
                 else if (exception is MqttCommunicationException)
                 {
@@ -406,7 +410,7 @@ namespace MQTTnet.Client
 
                 _packetDispatcher.Dispatch(exception);
 
-                if (_disconnectReason.TrySetException(exception))
+                if (!DisconnectIsPending())
                 {
                     await DisconnectInternalAsync(_packetReceiverTask, exception).ConfigureAwait(false);
                 }
@@ -492,16 +496,20 @@ namespace MQTTnet.Client
 
         private void StartReceivingPackets(CancellationToken cancellationToken)
         {
-            _packetReceiverTask = Task.Run(
+            _packetReceiverTask = Task.Factory.StartNew(
                 () => ReceivePacketsAsync(cancellationToken),
-                cancellationToken);
+                cancellationToken,
+                TaskCreationOptions.LongRunning, 
+                TaskScheduler.Default);
         }
 
         private void StartSendingKeepAliveMessages(CancellationToken cancellationToken)
         {
-            _keepAliveMessageSenderTask = Task.Run(
+            _keepAliveMessageSenderTask = Task.Factory.StartNew(
                 () => SendKeepAliveMessagesAsync(cancellationToken),
-                cancellationToken);
+                cancellationToken,
+                TaskCreationOptions.LongRunning,
+                TaskScheduler.Default);
         }
 
         private void FireApplicationMessageReceivedEvent(MqttPublishPacket publishPacket)
@@ -537,5 +545,10 @@ namespace MQTTnet.Client
             {
             }
         }
+
+        private bool DisconnectIsPending()
+        {
+            return Interlocked.CompareExchange(ref _disconnectGate, 1, 0) != 0;
+        }
     }
 }

Tests/MQTTnet.Core.Tests/MqttServerTests.cs

@@ -8,6 +8,7 @@ using System.Collections.Generic;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
+using MQTTnet.Adapter;
 using MQTTnet.Implementations;
 
 namespace MQTTnet.Core.Tests
@@ -552,6 +553,51 @@ namespace MQTTnet.Core.Tests
             Assert.IsTrue(bodyIsMatching);
         }
 
+        [TestMethod]
+        public async Task MqttServer_ConnectionDenied()
+        {
+            var server = new MqttFactory().CreateMqttServer();
+            var client = new MqttFactory().CreateMqttClient();
+
+            try
+            {
+                var options = new MqttServerOptionsBuilder().WithConnectionValidator(context =>
+                {
+                    context.ReturnCode = MqttConnectReturnCode.ConnectionRefusedNotAuthorized;
+                }).Build();
+
+                await server.StartAsync(options);
+
+                
+                var clientOptions = new MqttClientOptionsBuilder()
+                    .WithTcpServer("localhost").Build();
+
+                try
+                {
+                    await client.ConnectAsync(clientOptions);
+                    Assert.Fail("An exception should be raised.");
+                }
+                catch (Exception exception)
+                {
+                    if (exception is MqttConnectingFailedException)
+                    {
+
+                    }
+                    else
+                    {
+                        Assert.Fail("Wrong exception.");
+                    }
+                }
+            }
+            finally
+            {
+                await client.DisconnectAsync();
+                await server.StopAsync();
+                
+                client.Dispose();
+            }
+        }
+
         [TestMethod]
         public async Task MqttServer_SameClientIdConnectDisconnectEventOrder()
         {
@@ -623,25 +669,24 @@ namespace MQTTnet.Core.Tests
             MqttQualityOfServiceLevel filterQualityOfServiceLevel,
             int expectedReceivedMessagesCount)
         {
-            var serverAdapter = new TestMqttServerAdapter();
-            var s = new MqttFactory().CreateMqttServer(new[] { serverAdapter }, new MqttNetLogger());
+            var s = new MqttFactory().CreateMqttServer();
 
             var receivedMessagesCount = 0;
             try
             {
                 await s.StartAsync(new MqttServerOptions());
 
-                var c1 = await serverAdapter.ConnectTestClient("c1");
-                var c2 = await serverAdapter.ConnectTestClient("c2");
-
+                var c1 = new MqttFactory().CreateMqttClient();
                 c1.ApplicationMessageReceived += (_, __) => receivedMessagesCount++;
-
+                await c1.ConnectAsync(new MqttClientOptionsBuilder().WithTcpServer("localhost").Build());
                 await c1.SubscribeAsync(new TopicFilterBuilder().WithTopic(topicFilter).WithQualityOfServiceLevel(filterQualityOfServiceLevel).Build());
+
+                var c2 = new MqttFactory().CreateMqttClient();
+                await c2.ConnectAsync(new MqttClientOptionsBuilder().WithTcpServer("localhost").Build());
                 await c2.PublishAsync(builder => builder.WithTopic(topic).WithPayload(new byte[0]).WithQualityOfServiceLevel(qualityOfServiceLevel));
 
                 await Task.Delay(500);
                 await c1.UnsubscribeAsync(topicFilter);
-
                 await Task.Delay(500);
             }
             finally