Merge branch 'develop' into client-cancel-task

Source/MQTTnet.AspnetCore/AspNetMqttServerOptionsBuilder.cs

@@ -0,0 +1,15 @@
+using MQTTnet.Server;
+using System;
+
+namespace MQTTnet.AspNetCore
+{
+    public class AspNetMqttServerOptionsBuilder : MqttServerOptionsBuilder
+    {
+        public AspNetMqttServerOptionsBuilder(IServiceProvider serviceProvider)
+        {
+            ServiceProvider = serviceProvider;
+        }
+
+        public IServiceProvider ServiceProvider { get; }
+    }
+}

Source/MQTTnet.AspnetCore/ServiceCollectionExtensions.cs

@@ -20,14 +20,27 @@ namespace MQTTnet.AspNetCore
 
             return services;
         }
-        
+
         public static IServiceCollection AddHostedMqttServer(this IServiceCollection services, Action<MqttServerOptionsBuilder> configure)
         {
-            var builder = new MqttServerOptionsBuilder();
+            services.AddSingleton<IMqttServerOptions>(s => {
+                var builder = new MqttServerOptionsBuilder();
+                configure(builder);
+                return builder.Build();
+            });
 
-            configure(builder);
-            
-            services.AddSingleton<IMqttServerOptions>(builder.Build());
+            services.AddHostedMqttServer();
+
+            return services;
+        }
+
+        public static IServiceCollection AddHostedMqttServerWithServices(this IServiceCollection services, Action<AspNetMqttServerOptionsBuilder> configure)
+        {
+            services.AddSingleton<IMqttServerOptions>(s => {
+                var builder = new AspNetMqttServerOptionsBuilder(s);
+                configure(builder);
+                return builder.Build();
+            });
 
             services.AddHostedMqttServer();
 

Source/MQTTnet.Extensions.ManagedClient/MQTTnet.Extensions.ManagedClient.csproj

@@ -1,7 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard1.3;netstandard2.0;net452;net461;uap10.0</TargetFrameworks>
+    <TargetFrameworks>netstandard1.3;netstandard2.0;net452;net461</TargetFrameworks>
+    <TargetFrameworks Condition=" '$(OS)' == 'Windows_NT' AND '$(MSBuildRuntimeType)' != 'Core'">$(TargetFrameworks);uap10.0</TargetFrameworks>
     <Product />
     <Company />
     <Authors />

Source/MQTTnet.Extensions.ManagedClient/ManagedMqttClient.cs

@@ -226,7 +226,7 @@ namespace MQTTnet.Extensions.ManagedClient
         {
             try
             {
-                while (!cancellationToken.IsCancellationRequested)
+                while (!cancellationToken.IsCancellationRequested && _mqttClient.IsConnected)
                 {
                     var message = _messageQueue.Take(cancellationToken);
                     if (message == null)
@@ -306,15 +306,15 @@ namespace MQTTnet.Extensions.ManagedClient
 
             try
             {
-                if (subscriptions.Any())
-                {
-                    await _mqttClient.SubscribeAsync(subscriptions).ConfigureAwait(false);
-                }
-
                 if (unsubscriptions.Any())
                 {
                     await _mqttClient.UnsubscribeAsync(unsubscriptions).ConfigureAwait(false);
                 }
+
+                if (subscriptions.Any())
+                {
+                    await _mqttClient.SubscribeAsync(subscriptions).ConfigureAwait(false);
+                }
             }
             catch (Exception exception)
             {
@@ -367,7 +367,6 @@ namespace MQTTnet.Extensions.ManagedClient
             }
 
             var cts = new CancellationTokenSource();
-
             _publishingCancellationToken = cts;
 
             Task.Factory.StartNew(() => PublishQueuedMessages(cts.Token), cts.Token, TaskCreationOptions.LongRunning, TaskScheduler.Default);

Source/MQTTnet.Extensions.Rpc/MQTTnet.Extensions.Rpc.csproj

@@ -1,7 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard1.3;netstandard2.0;net452;net461;uap10.0</TargetFrameworks>
+    <TargetFrameworks>netstandard1.3;netstandard2.0;net452;net461</TargetFrameworks>
+    <TargetFrameworks Condition=" '$(OS)' == 'Windows_NT' AND '$(MSBuildRuntimeType)' != 'Core'">$(TargetFrameworks);uap10.0</TargetFrameworks>
     <Product />
     <Company />
     <Authors />

Source/MQTTnet/Client/IMqttClientFactory.cs

@@ -7,5 +7,9 @@ namespace MQTTnet.Client
         IMqttClient CreateMqttClient();
 
         IMqttClient CreateMqttClient(IMqttNetLogger logger);
+
+        IMqttClient CreateMqttClient(IMqttClientAdapterFactory adapterFactory);
+
+        IMqttClient CreateMqttClient(IMqttNetLogger logger, IMqttClientAdapterFactory adapterFactory);
     }
 }

Source/MQTTnet/Client/MqttClient.cs

@@ -25,10 +25,11 @@ namespace MQTTnet.Client
 
         private IMqttClientOptions _options;
         private CancellationTokenSource _cancellationTokenSource;
-        private Task _packetReceiverTask;
-        private Task _keepAliveMessageSenderTask;
+        internal Task _packetReceiverTask;
+        internal Task _keepAliveMessageSenderTask;
         private IMqttChannelAdapter _adapter;
         private bool _cleanDisconnectInitiated;
+        private TaskCompletionSource<bool> _disconnectReason;
 
         public MqttClient(IMqttClientAdapterFactory channelFactory, IMqttNetLogger logger)
         {
@@ -54,6 +55,7 @@ namespace MQTTnet.Client
             try
             {
                 _cancellationTokenSource = new CancellationTokenSource();
+                _disconnectReason = new TaskCompletionSource<bool>();
                 _options = options;
                 _packetIdentifierProvider.Reset();
                 _packetDispatcher.Reset();
@@ -85,8 +87,10 @@ namespace MQTTnet.Client
             catch (Exception exception)
             {
                 _logger.Error(exception, "Error while connecting with server.");
-                await DisconnectInternalAsync(null, exception).ConfigureAwait(false);
-
+                if (_disconnectReason.TrySetException(exception))
+                {
+                    await DisconnectInternalAsync(null, exception).ConfigureAwait(false);
+                }
                 throw;
             }
         }
@@ -104,7 +108,10 @@ namespace MQTTnet.Client
             }
             finally
             {
-                await DisconnectInternalAsync(null, null).ConfigureAwait(false);
+                if (_disconnectReason.TrySetCanceled())
+                {
+                    await DisconnectInternalAsync(null, null).ConfigureAwait(false);
+                }
             }
         }
 
@@ -351,7 +358,10 @@ namespace MQTTnet.Client
                     _logger.Error(exception, "Unhandled exception while sending/receiving keep alive packets.");
                 }
 
-                await DisconnectInternalAsync(_keepAliveMessageSenderTask, exception).ConfigureAwait(false);
+                if (_disconnectReason.TrySetException(exception))
+                {
+                    await DisconnectInternalAsync(_keepAliveMessageSenderTask, exception).ConfigureAwait(false);
+                }
             }
             finally
             {
@@ -395,7 +405,11 @@ namespace MQTTnet.Client
                 }
 
                 _packetDispatcher.Dispatch(exception);
-                await DisconnectInternalAsync(_packetReceiverTask, exception).ConfigureAwait(false);
+
+                if (_disconnectReason.TrySetException(exception))
+                {
+                    await DisconnectInternalAsync(_packetReceiverTask, exception).ConfigureAwait(false);
+                }
             }
             finally
             {

Source/MQTTnet/Client/MqttClientOptionsBuilder.cs

@@ -7,10 +7,11 @@ namespace MQTTnet.Client
     public class MqttClientOptionsBuilder
     {
         private readonly MqttClientOptions _options = new MqttClientOptions();
+
         private MqttClientTcpOptions _tcpOptions;
         private MqttClientWebSocketOptions _webSocketOptions;
-
-        private MqttClientTlsOptions _tlsOptions;
+        private MqttClientOptionsBuilderTlsParameters _tlsParameters;
+        private MqttClientWebSocketProxyOptions _proxyOptions;
 
         public MqttClientOptionsBuilder WithProtocolVersion(MqttProtocolVersion value)
         {
@@ -76,6 +77,21 @@ namespace MQTTnet.Client
             return this;
         }
 
+        public MqttClientOptionsBuilder WithProxy(string address, string username = null, string password = null, string domain = null, bool bypassOnLocal = false, string[] bypassList = null)
+        {
+            _proxyOptions = new MqttClientWebSocketProxyOptions
+            {
+                Address = address,
+                Username = username,
+                Password = password,
+                Domain = domain,
+                BypassOnLocal = bypassOnLocal,
+                BypassList = bypassList
+            };
+
+            return this;
+        }
+
         public MqttClientOptionsBuilder WithWebSocketServer(string uri)
         {
             _webSocketOptions = new MqttClientWebSocketOptions
@@ -86,13 +102,25 @@ namespace MQTTnet.Client
             return this;
         }
 
+        public MqttClientOptionsBuilder WithTls(MqttClientOptionsBuilderTlsParameters parameters)
+        {
+            _tlsParameters = parameters ?? throw new ArgumentNullException(nameof(parameters));
+            return this;
+        }
+
+        public MqttClientOptionsBuilder WithTls()
+        {
+            return WithTls(new MqttClientOptionsBuilderTlsParameters { UseTls = true });
+        }
+
+        [Obsolete("Use method _WithTls_ which accepts the _MqttClientOptionsBuilderTlsParameters_.")]
         public MqttClientOptionsBuilder WithTls(
             bool allowUntrustedCertificates = false,
             bool ignoreCertificateChainErrors = false,
             bool ignoreCertificateRevocationErrors = false,
             params byte[][] certificates)
         {
-            _tlsOptions = new MqttClientTlsOptions
+            _tlsParameters = new MqttClientOptionsBuilderTlsParameters
             {
                 UseTls = true,
                 AllowUntrustedCertificates = allowUntrustedCertificates,
@@ -104,33 +132,47 @@ namespace MQTTnet.Client
             return this;
         }
 
-        public MqttClientOptionsBuilder WithTls()
-        {
-            _tlsOptions = new MqttClientTlsOptions
-            {
-                UseTls = true
-            };
-
-            return this;
-        }
-
         public IMqttClientOptions Build()
         {
-            if (_tlsOptions != null)
+            if (_tcpOptions == null && _webSocketOptions == null)
             {
-                if (_tcpOptions == null && _webSocketOptions == null)
+                throw new InvalidOperationException("A channel must be set.");
+            }
+
+            if (_tlsParameters != null)
+            {
+                if (_tlsParameters?.UseTls == true)
                 {
-                    throw new InvalidOperationException("A channel (TCP or WebSocket) must be set if TLS is configured.");
+                    var tlsOptions = new MqttClientTlsOptions
+                    {
+                        UseTls = true,
+                        SslProtocol = _tlsParameters.SslProtocol,
+                        AllowUntrustedCertificates = _tlsParameters.AllowUntrustedCertificates,
+                        Certificates = _tlsParameters.Certificates?.Select(c => c.ToArray()).ToList(),
+                        CertificateValidationCallback = _tlsParameters.CertificateValidationCallback,
+                        IgnoreCertificateChainErrors = _tlsParameters.IgnoreCertificateChainErrors,
+                        IgnoreCertificateRevocationErrors = _tlsParameters.IgnoreCertificateRevocationErrors
+                    };
+
+                    if (_tcpOptions != null)
+                    {
+                        _tcpOptions.TlsOptions = tlsOptions;
+                    }
+                    else if (_webSocketOptions != null)
+                    {
+                        _webSocketOptions.TlsOptions = tlsOptions;
+                    }
+                }
+            }
+
+            if (_proxyOptions != null)
+            {
+                if (_webSocketOptions == null)
+                {
+                    throw new InvalidOperationException("Proxies are only supported for WebSocket connections.");
                 }
 
-                if (_tcpOptions != null)
-                {
-                    _tcpOptions.TlsOptions = _tlsOptions;
-                }
-                else if (_webSocketOptions != null)
-                {
-                    _webSocketOptions.TlsOptions = _tlsOptions;
-                }
+                _webSocketOptions.ProxyOptions = _proxyOptions;
             }
 
             _options.ChannelOptions = (IMqttClientChannelOptions)_tcpOptions ?? _webSocketOptions;

Source/MQTTnet/Client/MqttClientOptionsBuilderTlsParameters.cs

@@ -0,0 +1,29 @@
+using System;
+using System.Collections.Generic;
+using System.Net.Security;
+using System.Security.Authentication;
+using System.Security.Cryptography.X509Certificates;
+
+namespace MQTTnet.Client
+{
+    public class MqttClientOptionsBuilderTlsParameters
+    {
+        public bool UseTls { get; set; }
+
+        public Func<X509Certificate, X509Chain, SslPolicyErrors, IMqttClientOptions, bool> CertificateValidationCallback
+        {
+            get;
+            set;
+        }
+
+        public SslProtocols SslProtocol { get; set; } = SslProtocols.Tls12;
+
+        public IEnumerable<IEnumerable<byte>> Certificates { get; set; }
+
+        public bool AllowUntrustedCertificates { get; set; }
+
+        public bool IgnoreCertificateChainErrors { get; set; }
+
+        public bool IgnoreCertificateRevocationErrors { get; set; }
+    }
+}

Source/MQTTnet/Client/MqttClientTlsOptions.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Net.Security;
 using System.Security.Cryptography.X509Certificates;
+using System.Security.Authentication;
 
 namespace MQTTnet.Client
 {
@@ -17,6 +18,8 @@ namespace MQTTnet.Client
 
         public List<byte[]> Certificates { get; set; }
 
+        public SslProtocols SslProtocol { get; set; } = SslProtocols.Tls12;
+
         public Func<X509Certificate, X509Chain, SslPolicyErrors, IMqttClientOptions, bool> CertificateValidationCallback { get; set; }
     }
 }

Source/MQTTnet/Client/MqttClientWebSocketOptions.cs

@@ -13,6 +13,8 @@ namespace MQTTnet.Client
 
         public CookieContainer CookieContainer { get; set; }
 
+        public MqttClientWebSocketProxyOptions ProxyOptions { get; set; }
+
         public MqttClientTlsOptions TlsOptions { get; set; } = new MqttClientTlsOptions();
 
         public override string ToString()

Source/MQTTnet/Client/MqttClientWebSocketProxyOptions.cs

@@ -0,0 +1,17 @@
+namespace MQTTnet.Client
+{
+    public class MqttClientWebSocketProxyOptions
+    {
+        public string Address { get; set; }
+
+        public string Username { get; set; }
+
+        public string Password { get; set; }
+
+        public string Domain { get; set; }
+
+        public bool BypassOnLocal { get; set; }
+
+        public string[] BypassList { get; set; }
+    }
+}

Source/MQTTnet/Implementations/MqttTcpChannel.cs

@@ -63,7 +63,7 @@ namespace MQTTnet.Implementations
             if (_options.TlsOptions.UseTls)
             {
                 sslStream = new SslStream(new NetworkStream(_socket, true), false, InternalUserCertificateValidationCallback);
-                await sslStream.AuthenticateAsClientAsync(_options.Server, LoadCertificates(), SslProtocols.Tls12, _options.TlsOptions.IgnoreCertificateRevocationErrors).ConfigureAwait(false);
+                await sslStream.AuthenticateAsClientAsync(_options.Server, LoadCertificates(), _options.TlsOptions.SslProtocol, _options.TlsOptions.IgnoreCertificateRevocationErrors).ConfigureAwait(false);
             }
 
             CreateStream(sslStream);
@@ -87,8 +87,14 @@ namespace MQTTnet.Implementations
 
         public void Dispose()
         {
-            TryDispose(_stream, () => _stream = null);
-            TryDispose(_socket, () => _socket = null);
+            Cleanup(ref _stream, (s) => s.Dispose());
+            Cleanup(ref _socket, (s) => {
+                if (s.Connected)
+                {
+                    s.Shutdown(SocketShutdown.Both);
+                }
+                s.Dispose();
+            });
         }
 
         private bool InternalUserCertificateValidationCallback(object sender, X509Certificate x509Certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
@@ -157,11 +163,16 @@ namespace MQTTnet.Implementations
             }
         }
 
-        private static void TryDispose(IDisposable disposable, Action afterDispose)
+        private static void Cleanup<T>(ref T item, Action<T> handler) where T : class
         {
+            var temp = item;
+            item = null;
             try
             {
-                disposable?.Dispose();
+                if (temp != null)
+                {
+                    handler(temp);
+                }
             }
             catch (ObjectDisposedException)
             {
@@ -169,10 +180,6 @@ namespace MQTTnet.Implementations
             catch (NullReferenceException)
             {
             }
-            finally
-            {
-                afterDispose();
-            }
         }
     }
 }

Source/MQTTnet/Implementations/MqttTcpServerListener.cs

@@ -78,8 +78,10 @@ namespace MQTTnet.Implementations
                         await sslStream.AuthenticateAsServerAsync(_tlsCertificate, false, SslProtocols.Tls12, false).ConfigureAwait(false);
                     }
 
-                    var protocol = _addressFamily == AddressFamily.InterNetwork ? "ipv4" : "ipv6";
-                    _logger.Verbose($"Client '{clientSocket.RemoteEndPoint}' accepted by TCP listener '{_socket.LocalEndPoint}, {protocol}'.");
+                    _logger.Verbose("Client '{0}' accepted by TCP listener '{1}, {2}'.",
+                        clientSocket.RemoteEndPoint,
+                        _socket.LocalEndPoint,
+                        _addressFamily == AddressFamily.InterNetwork ? "ipv4" : "ipv6");
 
                     var clientAdapter = new MqttChannelAdapter(new MqttTcpChannel(clientSocket, sslStream), new MqttPacketSerializer(), _logger);
                     ClientAccepted?.Invoke(this, new MqttServerAdapterClientAcceptedEventArgs(clientAdapter));

Source/MQTTnet/Implementations/MqttWebSocketChannel.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Net;
 using System.Net.WebSockets;
 using System.Security.Cryptography.X509Certificates;
 using System.Threading;
@@ -14,7 +15,7 @@ namespace MQTTnet.Implementations
         private readonly MqttClientWebSocketOptions _options;
 
         private WebSocket _webSocket;
-        
+
         public MqttWebSocketChannel(MqttClientWebSocketOptions options)
         {
             _options = options ?? throw new ArgumentNullException(nameof(options));
@@ -45,6 +46,11 @@ namespace MQTTnet.Implementations
 
             var clientWebSocket = new ClientWebSocket();
 
+            if (_options.ProxyOptions != null)
+            {
+                clientWebSocket.Options.Proxy = CreateProxy();
+            }
+
             if (_options.RequestHeaders != null)
             {
                 foreach (var requestHeader in _options.RequestHeaders)
@@ -132,5 +138,31 @@ namespace MQTTnet.Implementations
                 _webSocket = null;
             }
         }
+
+        private IWebProxy CreateProxy()
+        {
+            if (string.IsNullOrEmpty(_options.ProxyOptions?.Address))
+            {
+                return null;
+            }
+
+#if WINDOWS_UWP
+            throw new NotSupportedException("Proxies are not supported in UWP.");
+#elif NETSTANDARD1_3
+            throw new NotSupportedException("Proxies are not supported in netstandard 1.3.");
+#else
+            var proxyUri = new Uri(_options.ProxyOptions.Address);
+
+            if (!string.IsNullOrEmpty(_options.ProxyOptions.Username) && !string.IsNullOrEmpty(_options.ProxyOptions.Password))
+            {
+                var credentials =
+                    new NetworkCredential(_options.ProxyOptions.Username, _options.ProxyOptions.Password, _options.ProxyOptions.Domain);
+
+                return new WebProxy(proxyUri, _options.ProxyOptions.BypassOnLocal, _options.ProxyOptions.BypassList, credentials);
+            }
+
+            return new WebProxy(proxyUri, _options.ProxyOptions.BypassOnLocal, _options.ProxyOptions.BypassList);
+#endif
+        }
     }
 }

Source/MQTTnet/MQTTnet.csproj

@@ -1,8 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks Condition=" '$(OS)' == 'Windows_NT' ">netstandard1.3;netstandard2.0;net452;net461;uap10.0</TargetFrameworks>
-    <TargetFrameworks Condition=" '$(OS)' != 'Windows_NT' ">netstandard1.3;netstandard2.0</TargetFrameworks>
+    <TargetFrameworks>netstandard1.3;netstandard2.0</TargetFrameworks>
+    <TargetFrameworks Condition=" '$(OS)' == 'Windows_NT' ">$(TargetFrameworks);net452;net461</TargetFrameworks>
+    <TargetFrameworks Condition=" '$(OS)' == 'Windows_NT' AND '$(MSBuildRuntimeType)' != 'Core'">$(TargetFrameworks);uap10.0</TargetFrameworks>
     <AssemblyName>MQTTnet</AssemblyName>
     <RootNamespace>MQTTnet</RootNamespace>
     <GeneratePackageOnBuild>False</GeneratePackageOnBuild>

Source/MQTTnet/Properties/AssemblyInfo.cs

@@ -0,0 +1,5 @@
+using System.Runtime.CompilerServices;
+
+#if DEBUG
+[assembly:InternalsVisibleTo("MQTTnet.Core.Tests")]
+#endif

Source/MQTTnet/Server/IMqttClientSession.cs

@@ -14,7 +14,7 @@ namespace MQTTnet.Server
         void EnqueueApplicationMessage(MqttClientSession senderClientSession, MqttPublishPacket publishPacket);
         void ClearPendingApplicationMessages();
         
-        Task<bool> RunAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter);
+        Task RunAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter);
         void Stop(MqttClientDisconnectType disconnectType);
 
         Task SubscribeAsync(IList<TopicFilter> topicFilters);

Source/MQTTnet/Server/IMqttServerFactory.cs

@@ -8,6 +8,8 @@ namespace MQTTnet.Server
     {
         IMqttServer CreateMqttServer();
 
+        IMqttServer CreateMqttServer(IMqttNetLogger logger);
+
         IMqttServer CreateMqttServer(IEnumerable<IMqttServerAdapter> adapters, IMqttNetLogger logger);
     }
 }

Source/MQTTnet/Server/MqttClientKeepAliveMonitor.cs

@@ -14,9 +14,9 @@ namespace MQTTnet.Server
 
         private readonly IMqttClientSession _clientSession;
         private readonly IMqttNetChildLogger _logger;
-        
+
         private bool _isPaused;
-        
+
         public MqttClientKeepAliveMonitor(IMqttClientSession clientSession, IMqttNetChildLogger logger)
         {
             if (logger == null) throw new ArgumentNullException(nameof(logger));
@@ -76,7 +76,7 @@ namespace MQTTnet.Server
                     {
                         _logger.Warning(null, "Client '{0}': Did not receive any packet or keep alive signal.", _clientSession.ClientId);
                         _clientSession.Stop(MqttClientDisconnectType.NotClean);
-                        
+
                         return;
                     }
 
@@ -96,7 +96,7 @@ namespace MQTTnet.Server
             }
             finally
             {
-                _logger.Verbose("Client {0}: Stopped checking keep alive timeout.", _clientSession.ClientId);
+                _logger.Verbose("Client '{0}': Stopped checking keep alive timeout.", _clientSession.ClientId);
             }
         }
     }

Source/MQTTnet/Server/MqttClientSession.cs

@@ -29,6 +29,8 @@ namespace MQTTnet.Server
         private MqttApplicationMessage _willMessage;
         private bool _wasCleanDisconnect;
         private IMqttChannelAdapter _adapter;
+        private Task _workerTask;
+        private IDisposable _cleanupHandle;
 
         public MqttClientSession(
             string clientId,
@@ -65,7 +67,13 @@ namespace MQTTnet.Server
             status.LastNonKeepAlivePacketReceived = _keepAliveMonitor.LastNonKeepAlivePacketReceived;
         }
 
-        public async Task<bool> RunAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter)
+        public Task RunAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter)
+        {
+            _workerTask = RunInternalAsync(connectPacket, adapter);
+            return _workerTask;
+        }
+
+        private async Task RunInternalAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter)
         {
             if (connectPacket == null) throw new ArgumentNullException(nameof(connectPacket));
             if (adapter == null) throw new ArgumentNullException(nameof(adapter));
@@ -73,10 +81,18 @@ namespace MQTTnet.Server
             try
             {
                 _adapter = adapter;
+
                 adapter.ReadingPacketStarted += OnAdapterReadingPacketStarted;
                 adapter.ReadingPacketCompleted += OnAdapterReadingPacketCompleted;
 
                 _cancellationTokenSource = new CancellationTokenSource();
+
+                //woraround for https://github.com/dotnet/corefx/issues/24430
+#pragma warning disable 4014
+                _cleanupHandle = _cancellationTokenSource.Token.Register(() => CleanupAsync());
+#pragma warning restore 4014
+                //endworkaround
+
                 _wasCleanDisconnect = false;
                 _willMessage = connectPacket.WillMessage;
 
@@ -114,26 +130,55 @@ namespace MQTTnet.Server
                     _logger.Error(exception, "Client '{0}': Unhandled exception while receiving client packets.", ClientId);
                 }
 
-                Stop(MqttClientDisconnectType.NotClean);
+                Stop(MqttClientDisconnectType.NotClean, true);
             }
             finally
             {
-                if (_adapter != null)
-                {
-                    _adapter.ReadingPacketStarted -= OnAdapterReadingPacketStarted;
-                    _adapter.ReadingPacketCompleted -= OnAdapterReadingPacketCompleted;
-                }
+                await CleanupAsync().ConfigureAwait(false);
 
+                _cleanupHandle?.Dispose();
+                _cleanupHandle = null;
+                
                 _adapter = null;
-                _cancellationTokenSource?.Cancel ();
+                _cancellationTokenSource?.Cancel(false);
                 _cancellationTokenSource?.Dispose();
                 _cancellationTokenSource = null;
             }
+        }
 
-            return _wasCleanDisconnect;
+        private async Task CleanupAsync()
+        {
+            var adapter = _adapter;
+            try
+            {
+                if (adapter == null)
+                {
+                    return;
+                }
+
+                _adapter = null;
+
+                adapter.ReadingPacketStarted -= OnAdapterReadingPacketStarted;
+                adapter.ReadingPacketCompleted -= OnAdapterReadingPacketCompleted;
+
+                await adapter.DisconnectAsync(_options.DefaultCommunicationTimeout, CancellationToken.None).ConfigureAwait(false);
+            }
+            catch (Exception exception)
+            {
+                _logger.Error(exception, exception.Message);
+            }
+            finally
+            {
+                adapter?.Dispose();
+            }
         }
 
         public void Stop(MqttClientDisconnectType type)
+        {
+            Stop(type, false);
+        }
+
+        private void Stop(MqttClientDisconnectType type, bool isInsideSession)
         {
             try
             {
@@ -153,10 +198,17 @@ namespace MQTTnet.Server
                 }
 
                 _willMessage = null;
+
+                if (!isInsideSession)
+                {
+                    _workerTask?.GetAwaiter().GetResult();
+                }
             }
             finally
             {
                 _logger.Info("Client '{0}': Session stopped.", ClientId);
+
+                _sessionsManager.Server.OnClientDisconnected(ClientId, _wasCleanDisconnect);
             }
         }
 
@@ -300,18 +352,18 @@ namespace MQTTnet.Server
 
             if (packet is MqttDisconnectPacket)
             {
-                Stop(MqttClientDisconnectType.Clean);
+                Stop(MqttClientDisconnectType.Clean, true);
                 return;
             }
 
             if (packet is MqttConnectPacket)
             {
-                Stop(MqttClientDisconnectType.NotClean);
+                Stop(MqttClientDisconnectType.NotClean, true);
                 return;
             }
 
             _logger.Warning(null, "Client '{0}': Received not supported packet ({1}). Closing connection.", ClientId, packet);
-            Stop(MqttClientDisconnectType.NotClean);
+            Stop(MqttClientDisconnectType.NotClean, true);
         }
 
         private void EnqueueSubscribedRetainedMessages(ICollection<TopicFilter> topicFilters)
@@ -330,7 +382,7 @@ namespace MQTTnet.Server
 
             if (subscribeResult.CloseConnection)
             {
-                Stop(MqttClientDisconnectType.NotClean);
+                Stop(MqttClientDisconnectType.NotClean, true);
                 return;
             }
 
@@ -407,12 +459,12 @@ namespace MQTTnet.Server
 
         private void OnAdapterReadingPacketCompleted(object sender, EventArgs e)
         {
-            _keepAliveMonitor?.Pause();
+            _keepAliveMonitor?.Resume();
         }
 
         private void OnAdapterReadingPacketStarted(object sender, EventArgs e)
         {
-            _keepAliveMonitor?.Resume();
+            _keepAliveMonitor?.Pause();
         }
     }
 }

Source/MQTTnet/Server/MqttClientSessionsManager.cs

@@ -44,7 +44,7 @@ namespace MQTTnet.Server
 
         public void Start()
         {
-            Task.Factory.StartNew(() => ProcessQueuedApplicationMessages(_cancellationToken), _cancellationToken, TaskCreationOptions.LongRunning, TaskScheduler.Default);
+            Task.Factory.StartNew(() => TryProcessQueuedApplicationMessages(_cancellationToken), _cancellationToken, TaskCreationOptions.LongRunning, TaskScheduler.Default);
         }
 
         public void Stop()
@@ -125,6 +125,7 @@ namespace MQTTnet.Server
             {
                 _sessions.Remove(clientId);
             }
+
             _logger.Verbose("Session for client '{0}' deleted.", clientId);
         }
 
@@ -133,54 +134,69 @@ namespace MQTTnet.Server
             _messageQueue?.Dispose();
         }
 
-        private void ProcessQueuedApplicationMessages(CancellationToken cancellationToken)
+        private void TryProcessQueuedApplicationMessages(CancellationToken cancellationToken)
         {
             while (!cancellationToken.IsCancellationRequested)
             {
                 try
                 {
-                    var enqueuedApplicationMessage = _messageQueue.Take(cancellationToken);
-                    var sender = enqueuedApplicationMessage.Sender;
-                    var applicationMessage = enqueuedApplicationMessage.PublishPacket.ToApplicationMessage();
-
-                    var interceptorContext = InterceptApplicationMessage(sender, applicationMessage);
-                    if (interceptorContext != null)
-                    {
-                        if (interceptorContext.CloseConnection)
-                        {
-                            enqueuedApplicationMessage.Sender.Stop(MqttClientDisconnectType.NotClean);
-                        }
-
-                        if (interceptorContext.ApplicationMessage == null || !interceptorContext.AcceptPublish)
-                        {
-                            return;
-                        }
-
-                        applicationMessage = interceptorContext.ApplicationMessage;
-                    }
-
-                    Server.OnApplicationMessageReceived(sender?.ClientId, applicationMessage);
-
-                    if (applicationMessage.Retain)
-                    {
-                        _retainedMessagesManager.HandleMessageAsync(sender?.ClientId, applicationMessage).GetAwaiter().GetResult();
-                    }
-
-                    foreach (var clientSession in GetSessions())
-                    {
-                        clientSession.EnqueueApplicationMessage(enqueuedApplicationMessage.Sender, applicationMessage.ToPublishPacket());
-                    }
+                    TryProcessNextQueuedApplicationMessage(cancellationToken);
                 }
                 catch (OperationCanceledException)
                 {
                 }
                 catch (Exception exception)
                 {
-                    _logger.Error(exception, "Unhandled exception while processing queued application message.");
+                    _logger.Error(exception, "Unhandled exception while processing queued application messages.");
                 }
             }
         }
 
+        private void TryProcessNextQueuedApplicationMessage(CancellationToken cancellationToken)
+        {
+            try
+            {
+                var enqueuedApplicationMessage = _messageQueue.Take(cancellationToken);
+                var sender = enqueuedApplicationMessage.Sender;
+                var applicationMessage = enqueuedApplicationMessage.PublishPacket.ToApplicationMessage();
+
+                var interceptorContext = InterceptApplicationMessage(sender, applicationMessage);
+                if (interceptorContext != null)
+                {
+                    if (interceptorContext.CloseConnection)
+                    {
+                        enqueuedApplicationMessage.Sender.Stop(MqttClientDisconnectType.NotClean);
+                    }
+
+                    if (interceptorContext.ApplicationMessage == null || !interceptorContext.AcceptPublish)
+                    {
+                        return;
+                    }
+
+                    applicationMessage = interceptorContext.ApplicationMessage;
+                }
+
+                Server.OnApplicationMessageReceived(sender?.ClientId, applicationMessage);
+
+                if (applicationMessage.Retain)
+                {
+                    _retainedMessagesManager.HandleMessageAsync(sender?.ClientId, applicationMessage).GetAwaiter().GetResult();
+                }
+
+                foreach (var clientSession in GetSessions())
+                {
+                    clientSession.EnqueueApplicationMessage(enqueuedApplicationMessage.Sender, applicationMessage.ToPublishPacket());
+                }
+            }
+            catch (OperationCanceledException)
+            {
+            }
+            catch (Exception exception)
+            {
+                _logger.Error(exception, "Unhandled exception while processing next queued application message.");
+            }
+        }
+
         private List<MqttClientSession> GetSessions()
         {
             lock (_sessions)
@@ -192,8 +208,7 @@ namespace MQTTnet.Server
         private async Task RunSession(IMqttChannelAdapter clientAdapter, CancellationToken cancellationToken)
         {
             var clientId = string.Empty;
-            var wasCleanDisconnect = false;
-
+            
             try
             {
                 var firstPacket = await clientAdapter.ReceivePacketAsync(_options.DefaultCommunicationTimeout, cancellationToken).ConfigureAwait(false);
@@ -238,7 +253,7 @@ namespace MQTTnet.Server
 
                 Server.OnClientConnected(clientId);
 
-                wasCleanDisconnect = await clientSession.RunAsync(connectPacket, clientAdapter).ConfigureAwait(false);
+                await clientSession.RunAsync(connectPacket, clientAdapter).ConfigureAwait(false);
             }
             catch (OperationCanceledException)
             {
@@ -249,22 +264,10 @@ namespace MQTTnet.Server
             }
             finally
             {
-                try
-                {
-                    await clientAdapter.DisconnectAsync(_options.DefaultCommunicationTimeout, CancellationToken.None).ConfigureAwait(false);
-                    clientAdapter.Dispose();
-                }
-                catch (Exception exception)
-                {
-                    _logger.Error(exception, exception.Message);
-                }
-
                 if (!_options.EnablePersistentSessions)
                 {
                     DeleteSession(clientId);
                 }
-
-                Server.OnClientDisconnected(clientId, wasCleanDisconnect);
             }
         }
 

Source/MQTTnet/Server/MqttServer.cs

@@ -106,14 +106,14 @@ namespace MQTTnet.Server
 
                 _cancellationTokenSource.Cancel(false);
                 
+                _clientSessionsManager.Stop();
+
                 foreach (var adapter in _adapters)
                 {
                     adapter.ClientAccepted -= OnClientAccepted;
                     await adapter.StopAsync().ConfigureAwait(false);
                 }
 
-                _clientSessionsManager.Stop();
-
                 _logger.Info("Stopped.");
                 Stopped?.Invoke(this, EventArgs.Empty);
             }