Merge branch 'develop' into ServerShutdown

Build/MQTTnet.nuspec

@@ -11,11 +11,11 @@
     <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] Performance optimizations.
-* [Core] Fixed a bug which prevents receiving large packets (UWP only)
+* [Client] Added support for proxies when using web socket connections (thanks to PitySOFT).
-* [Client] The ManagedClient options now allow configuring the interval for connection checks.
+* [Client] Refactored TLS parameter usage and added more parameters (thanks to PitySOFT).
-* [Server] Added the Endpoint of the Adapter (remote IP and port) to the connection validation callback.
+* [Server] Fixed an issue in client keep alive checks (thanks to @jenscski).
-* [Server] The ipv4 and ipv6 endpoint can be disabled now by setting the bound IP address to _None_.
+* [Server] Changed the order of _ClientConnected_ and _ClientDisconnected_ events so that _ClientConnected_ is fired at first (thanks to @jenscski).
-* [Server] Fix a bug in the keep alive monitor which caused high CPU load (thanks to @GarageGadget).
+* [Server] Fixed an iussue which lets the server stop processing messages when using the application message interceptor (thanks to @alamsor).
     </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> 
@@ -56,6 +56,9 @@
     <file src="..\Source\MQTTnet\bin\Release\net452\MQTTnet.*" target="lib\net452\"/>
 
     <file src="..\Source\MQTTnet\bin\Release\netstandard2.0\MQTTnet.*" target="lib\net461\"/>
+    <file src="..\Source\MQTTnet\bin\Release\netstandard2.0\MQTTnet.*" target="lib\net462\"/>
+    <file src="..\Source\MQTTnet\bin\Release\netstandard2.0\MQTTnet.*" target="lib\net470\"/>
+    <file src="..\Source\MQTTnet\bin\Release\netstandard2.0\MQTTnet.*" target="lib\net471\"/>
     <file src="..\Source\MQTTnet\bin\Release\netstandard2.0\MQTTnet.*" target="lib\net472\"/>
   </files>
 </package>

README.md

@@ -83,9 +83,10 @@ This project also listed at Open Collective (https://opencollective.com/mqttnet)
 
 This library is used in the following projects:
 
+* HA4IoT (Open Source Home Automation system for .NET, <https://github.com/chkr1011/HA4IoT>)
 * MQTT Client Rx (Wrapper for Reactive Extensions, <https://github.com/1iveowl/MQTTClient.rx>)
 * MQTT Tester (MQTT client test app for [Android](https://play.google.com/store/apps/details?id=com.liveowl.mqtttester) and [iOS](https://itunes.apple.com/us/app/mqtt-tester/id1278621826?mt=8))
-* HA4IoT (Open Source Home Automation system for .NET, <https://github.com/chkr1011/HA4IoT>)
+* Wirehome.Core (Open Source Home Automation system for .NET Core, <https://github.com/chkr1011/Wirehome.Core>)
 
 If you use this library and want to see your project here please let me know.
 

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 MqttClientOptionsBuilderTlsParameters _tlsParameters;
-        private MqttClientTlsOptions _tlsOptions;
+        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)
+                _webSocketOptions.ProxyOptions = _proxyOptions;
-                {
-                    _tcpOptions.TlsOptions = _tlsOptions;
-                }
-                else if (_webSocketOptions != null)
-                {
-                    _webSocketOptions.TlsOptions = _tlsOptions;
-                }
             }
 
             _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);

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/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/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

@@ -67,13 +67,13 @@ namespace MQTTnet.Server
             status.LastNonKeepAlivePacketReceived = _keepAliveMonitor.LastNonKeepAlivePacketReceived;
         }
 
-        public Task<bool> RunAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter)
+        public Task RunAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter)
         {
             _workerTask = RunInternalAsync(connectPacket, adapter);
             return _workerTask;
         }
 
-        private async Task<bool> RunInternalAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter)
+        private async Task RunInternalAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter)
         {
             if (connectPacket == null) throw new ArgumentNullException(nameof(connectPacket));
             if (adapter == null) throw new ArgumentNullException(nameof(adapter));
@@ -138,8 +138,6 @@ namespace MQTTnet.Server
                 _cancellationTokenSource?.Dispose();
                 _cancellationTokenSource = null;
             }
-
-            return _wasCleanDisconnect;
         }
 
         private async Task Cleanup()
@@ -199,6 +197,8 @@ namespace MQTTnet.Server
             finally
             {
                 _logger.Info("Client '{0}': Session stopped.", ClientId);
+
+                _sessionsManager.Server.OnClientDisconnected(ClientId, _wasCleanDisconnect);
             }
         }
 
@@ -447,12 +447,12 @@ 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);
+                    TryProcessNextQueuedApplicationMessage(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 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)
             {
@@ -253,8 +268,6 @@ namespace MQTTnet.Server
                 {
                     DeleteSession(clientId);
                 }
-
-                Server.OnClientDisconnected(clientId, wasCleanDisconnect);
             }
         }
 

Tests/MQTTnet.Core.Tests/MqttClientTests.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Net.Sockets;
 using System.Threading;
 using System.Threading.Tasks;
@@ -8,13 +8,14 @@ using MQTTnet.Client;
 using MQTTnet.Diagnostics;
 using MQTTnet.Exceptions;
 using MQTTnet.Packets;
+using MQTTnet.Implementations;
+using MQTTnet.Server;
 
 namespace MQTTnet.Core.Tests
 {
     [TestClass]
     public class MqttClientTests
     {
-
         [TestMethod]
         public async Task ClientDisconnectException()
         {

Tests/MQTTnet.Core.Tests/MqttKeepAliveMonitorTests.cs

@@ -60,7 +60,7 @@ namespace MQTTnet.Core.Tests
         {
             public string ClientId { get; }
 
-            public int StopCalledCount { get; set; }
+            public int StopCalledCount { get; private set; }
 
             public void FillStatus(MqttClientSessionStatus status)
             {
@@ -77,7 +77,7 @@ namespace MQTTnet.Core.Tests
                 throw new NotSupportedException();
             }
 
-            public Task<bool> RunAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter)
+            public Task RunAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter)
             {
                 throw new NotSupportedException();
             }

Tests/MQTTnet.Core.Tests/MqttServerTests.cs

@@ -552,6 +552,54 @@ namespace MQTTnet.Core.Tests
             Assert.IsTrue(bodyIsMatching);
         }
 
+        [TestMethod]
+        public async Task MqttServer_SameClientIdConnectDisconnectEventOrder()
+        {
+            var serverAdapter = new MqttTcpServerAdapter(new MqttNetLogger().CreateChildLogger());
+            var s = new MqttFactory().CreateMqttServer(new[] { serverAdapter }, new MqttNetLogger());
+
+            var connectedClient = false;
+            var connecteCalledBeforeConnectedClients = false;
+
+            s.ClientConnected += (_, __) =>
+            {
+                connecteCalledBeforeConnectedClients |= connectedClient;
+                connectedClient = true;
+            };
+
+            s.ClientDisconnected += (_, __) =>
+            {
+                connectedClient = false;
+            };
+
+            var clientOptions = new MqttClientOptionsBuilder()
+                .WithTcpServer("localhost")
+                .WithClientId(Guid.NewGuid().ToString())
+                .Build();
+
+            await s.StartAsync(new MqttServerOptions());
+
+            var c1 = new MqttFactory().CreateMqttClient();
+            var c2 = new MqttFactory().CreateMqttClient();
+
+            await c1.ConnectAsync(clientOptions);
+
+            await Task.Delay(100);
+
+            await c2.ConnectAsync(clientOptions);
+
+            await Task.Delay(100);
+
+            await c1.DisconnectAsync();
+            await c2.DisconnectAsync();
+
+            await s.StopAsync();
+
+            await Task.Delay(100);
+
+            Assert.IsFalse(connecteCalledBeforeConnectedClients, "ClientConnected was called before ClientDisconnect was called");
+        }
+
         private class TestStorage : IMqttServerStorage
         {
             public IList<MqttApplicationMessage> Messages = new List<MqttApplicationMessage>();