Code cleanup.

Source/MQTTnet.AspnetCore/ServiceCollectionExtensions.cs

@@ -40,7 +40,7 @@ namespace MQTTnet.AspNetCore
 
         public static IServiceCollection AddHostedMqttServer(this IServiceCollection services, Action<MqttServerOptionsBuilder> configure = null)
         {
-            services.AddSingleton<MqttServerOptions>(s =>
+            services.AddSingleton(s =>
             {
                 var serverOptionsBuilder = new MqttServerOptionsBuilder();
                 configure?.Invoke(serverOptionsBuilder);
@@ -54,7 +54,7 @@ namespace MQTTnet.AspNetCore
 
         public static IServiceCollection AddHostedMqttServerWithServices(this IServiceCollection services, Action<AspNetMqttServerOptionsBuilder> configure)
         {
-            services.AddSingleton<MqttServerOptions>(s =>
+            services.AddSingleton(s =>
             {
                 var builder = new AspNetMqttServerOptionsBuilder(s);
                 configure(builder);

Source/MQTTnet.Benchmarks/ChannelAdapterBenchmark.cs

@@ -11,6 +11,7 @@ using System.IO;
 using System.Threading;
 using MQTTnet.Diagnostics;
 using MQTTnet.Formatter;
+using MQTTnet.Tests.Mockups;
 
 namespace MQTTnet.Benchmarks
 {

Source/MQTTnet.Extensions.WebSocket4Net/WebSocket4NetMqttChannel.cs

@@ -56,9 +56,9 @@ namespace MQTTnet.Extensions.WebSocket4Net
             }
 
 #if NET48 || NETCOREAPP3_1 || NET5 || NET6
-            var sslProtocols = _webSocketOptions?.TlsOptions.SslProtocol ?? SslProtocols.Tls12 | SslProtocols.Tls13;
+            var sslProtocols = _webSocketOptions?.TlsOptions?.SslProtocol ?? SslProtocols.Tls12 | SslProtocols.Tls13;
 #else
-            var sslProtocols = _webSocketOptions?.TlsOptions.SslProtocol ?? SslProtocols.Tls12 | (SslProtocols)0x00003000 /*Tls13*/;
+            var sslProtocols = _webSocketOptions?.TlsOptions?.SslProtocol ?? SslProtocols.Tls12 | (SslProtocols)0x00003000 /*Tls13*/;
 #endif
 
             var subProtocol = _webSocketOptions.SubProtocols.FirstOrDefault() ?? string.Empty;

Source/MQTTnet.Tests/Formatter/MqttPacketSerialization_V3_Binary_Tests.cs

@@ -17,6 +17,7 @@ using MQTTnet.Internal;
 using MQTTnet.Packets;
 using MQTTnet.Protocol;
 using MQTTnet.Tests.Extensions;
+using MQTTnet.Tests.Mockups;
 
 namespace MQTTnet.Tests
 {

Source/MQTTnet/Internal/TestMqttChannel.cs → Source/MQTTnet.Tests/Mockups/TestMqttChannel.cs

@@ -8,7 +8,7 @@ using System.Threading;
 using System.Threading.Tasks;
 using MQTTnet.Channel;
 
-namespace MQTTnet.Internal
+namespace MQTTnet.Tests.Mockups
 {
     public sealed class TestMqttChannel : IMqttChannel
     {

Source/MQTTnet.Tests/MqttPacketSerializationHelper.cs

@@ -5,6 +5,7 @@ using MQTTnet.Diagnostics;
 using MQTTnet.Formatter;
 using MQTTnet.Internal;
 using MQTTnet.Packets;
+using MQTTnet.Tests.Mockups;
 
 namespace MQTTnet.Tests
 {

Source/MQTTnet/Client/Options/MqttClientOptionsBuilderTlsParameters.cs

@@ -10,7 +10,7 @@ using System.Security.Cryptography.X509Certificates;
 
 namespace MQTTnet.Client
 {
-    public class MqttClientOptionsBuilderTlsParameters
+    public sealed class MqttClientOptionsBuilderTlsParameters
     {
         public bool UseTls { get; set; }
         

Source/MQTTnet/Client/Unsubscribing/MqttClientUnsubscribeResultFactory.cs

@@ -4,7 +4,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using MQTTnet.Exceptions;
 using MQTTnet.Packets;
 

Source/MQTTnet/Diagnostics/Logger/MqttNetNullLogger.cs

@@ -7,12 +7,17 @@ using System;
 namespace MQTTnet.Diagnostics
 {
     /// <summary>
-    /// This logger does nothing with the messages.
+    ///     This logger does nothing with the messages.
     /// </summary>
     public sealed class MqttNetNullLogger : IMqttNetLogger
     {
+        public MqttNetNullLogger()
+        {
+            IsEnabled = false;
+        }
+
         public static MqttNetNullLogger Instance { get; } = new MqttNetNullLogger();
-        
+
         public bool IsEnabled { get; }
 
         public void Publish(MqttNetLogLevel logLevel, string source, string message, object[] parameters, Exception exception)

Source/MQTTnet/Formatter/MqttBufferReader.cs

@@ -3,12 +3,10 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Collections.Generic;
 using System.Runtime.CompilerServices;
 using System.Text;
 using MQTTnet.Exceptions;
 using MQTTnet.Implementations;
-using MQTTnet.Protocol;
 
 namespace MQTTnet.Formatter
 {

Source/MQTTnet/Implementations/CrossPlatformSocket.cs

@@ -47,7 +47,7 @@ namespace MQTTnet.Implementations
             // We cannot use the _NoDelay_ property from the socket because there is an issue in .NET 4.5.2, 4.6.
             // The decompiled code is: this.SetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.Debug, value ? 1 : 0);
             // Which is wrong because the "NoDelay" should be set and not "Debug".
-            get => (int)_socket.GetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.NoDelay) != 0;
+            get => (int?)_socket.GetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.NoDelay) != 0;
             set => _socket.SetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.NoDelay, value ? 1 : 0);
         }
 

Source/MQTTnet/MqttTopicFilterBuilder.cs

@@ -4,7 +4,6 @@
 
 using MQTTnet.Exceptions;
 using MQTTnet.Protocol;
-using System;
 using MQTTnet.Packets;
 
 namespace MQTTnet

Source/MQTTnet/Server/Events/InterceptingPublishEventArgs.cs

@@ -4,41 +4,40 @@
 
 using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Threading;
 
 namespace MQTTnet.Server
 {
     public sealed class InterceptingPublishEventArgs : EventArgs
-    { 
+    {
+        public MqttApplicationMessage ApplicationMessage { get; set; }
+
         /// <summary>
-        /// Gets the client identifier.
-        /// Hint: This identifier needs to be unique over all used clients / devices on the broker to avoid connection issues.
+        ///     Gets the cancellation token which can indicate that the client connection gets down.
+        /// </summary>
+        public CancellationToken CancellationToken { get; internal set; }
+
+        /// <summary>
+        ///     Gets the client identifier.
+        ///     Hint: This identifier needs to be unique over all used clients / devices on the broker to avoid connection issues.
         /// </summary>
         public string ClientId { get; internal set; }
 
-        public MqttApplicationMessage ApplicationMessage { get; set; }
+        public bool CloseConnection { get; set; }
 
         /// <summary>
-        /// Gets or sets a key/value collection that can be used to share data within the scope of this session.
+        ///     Gets or sets whether the publish should be processed internally.
         /// </summary>
-        public IDictionary SessionItems { get; internal set; }
+        public bool ProcessPublish { get; set; } = true;
 
         /// <summary>
-        /// Gets the response which will be sent to the client via the PUBACK etc. packets.
+        ///     Gets the response which will be sent to the client via the PUBACK etc. packets.
         /// </summary>
         public PublishResponse Response { get; } = new PublishResponse();
-        
-        /// <summary>
-        /// Gets or sets whether the publish should be processed internally.
-        /// </summary>
-        public bool ProcessPublish { get; set; } = true;
-        
-        public bool CloseConnection { get; set; }
-        
+
         /// <summary>
-        /// Gets the cancellation token which can indicate that the client connection gets down.
+        ///     Gets or sets a key/value collection that can be used to share data within the scope of this session.
         /// </summary>
-        public CancellationToken CancellationToken { get; internal set; }
+        public IDictionary SessionItems { get; internal set; }
     }
-}
+}

Source/MQTTnet/Server/Events/InterceptingUnsubscriptionEventArgs.cs

@@ -4,7 +4,6 @@
 
 using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Threading;
 
 namespace MQTTnet.Server
@@ -12,43 +11,45 @@ namespace MQTTnet.Server
     public sealed class InterceptingUnsubscriptionEventArgs : EventArgs
     {
         /// <summary>
-        /// Gets the client identifier.
-        /// Hint: This identifier needs to be unique over all used clients / devices on the broker to avoid connection issues.
+        ///     Gets the cancellation token which can indicate that the client connection gets down.
         /// </summary>
-        public string ClientId { get; internal set; }
+        public CancellationToken CancellationToken { get; internal set; }
 
         /// <summary>
-        /// Gets or sets the MQTT topic.
-        /// In MQTT, the word topic refers to an UTF-8 string that the broker uses to filter messages for each connected client.
-        /// The topic consists of one or more topic levels. Each topic level is separated by a forward slash (topic level separator). 
+        ///     Gets the client identifier.
+        ///     Hint: This identifier needs to be unique over all used clients / devices on the broker to avoid connection issues.
         /// </summary>
-        public string Topic { get; internal set; }
+        public string ClientId { get; internal set; }
 
         /// <summary>
-        /// Gets or sets a key/value collection that can be used to share data within the scope of this session.
+        ///     Gets or sets whether the broker should close the client connection.
         /// </summary>
-        public IDictionary SessionItems { get; internal set; }
+        public bool CloseConnection { get; set; }
 
         /// <summary>
-        /// Gets the response which will be sent to the client via the UNSUBACK pocket.
+        ///     Gets or sets whether the broker should remove an internal subscription for the client.
+        ///     The broker can also avoid this and return "success" to the client.
+        ///     This feature allows using the MQTT Broker as the Frontend and another system as the backend.
         /// </summary>
-        public UnsubscribeResponse Response { get; } = new UnsubscribeResponse();
-        
+        public bool ProcessUnsubscription { get; set; } = true;
+
         /// <summary>
-        /// Gets or sets whether the broker should remove an internal subscription for the client.
-        /// The broker can also avoid this and return "success" to the client.
-        /// This feature allows using the MQTT Broker as the Frontend and another system as the backend.
+        ///     Gets the response which will be sent to the client via the UNSUBACK pocket.
         /// </summary>
-        public bool ProcessUnsubscription { get; set; } = true;
-        
+        public UnsubscribeResponse Response { get; } = new UnsubscribeResponse();
+
         /// <summary>
-        /// Gets or sets whether the broker should close the client connection.
+        ///     Gets or sets a key/value collection that can be used to share data within the scope of this session.
         /// </summary>
-        public bool CloseConnection { get; set; }
-        
+        public IDictionary SessionItems { get; internal set; }
+
         /// <summary>
-        /// Gets the cancellation token which can indicate that the client connection gets down.
+        ///     Gets or sets the MQTT topic.
+        ///     In MQTT, the word topic refers to an UTF-8 string that the broker uses to filter messages for each connected
+        ///     client.
+        ///     The topic consists of one or more topic levels. Each topic level is separated by a forward slash (topic level
+        ///     separator).
         /// </summary>
-        public CancellationToken CancellationToken { get; internal set; }
+        public string Topic { get; internal set; }
     }
-}
+}

Source/MQTTnet/Server/Events/PreparingSessionEventArgs.cs

@@ -11,9 +11,9 @@ namespace MQTTnet.Server
     public sealed class PreparingSessionEventArgs : EventArgs
     {
         public string Id { get; internal set; }
-        
+
         // TODO: Allow adding of packets to the queue etc.
-        
+
         /*
          * The Session State in the Server consists of:
 ·         The existence of a Session, even if the rest of the Session State is empty.
@@ -23,28 +23,28 @@ namespace MQTTnet.Server
 ·         QoS 2 messages which have been received from the Client, but have not been completely acknowledged.The Will Message and the Will Delay Interval
 ·         If the Session is currently not connected, the time at which the Session will end and Session State will be discarded.
          */
-        
+
         public bool IsExistingSession { get; set; }
 
-        public List<MqttSubscription> Subscriptions { get; } = new List<MqttSubscription>();
+        public IDictionary<object, object> Items { get; set; }
 
         public List<MqttPublishPacket> PublishPackets { get; } = new List<MqttPublishPacket>();
-        
-        public IDictionary<object, object> Items { get; set; }
 
-        /// <summary>
-        /// Gets the last will message.
-        /// In MQTT, you use the last will message feature to notify other clients about an ungracefully disconnected client.
-        /// </summary>
-        // TODO: Use single properties. No entire will message.
-        MqttApplicationMessage WillMessage { get; set; }
+        DateTime? SessionExpiryTimestamp { get; set; }
+
+        public List<MqttSubscription> Subscriptions { get; } = new List<MqttSubscription>();
 
         /// <summary>
-        /// Gets the will delay interval.
-        /// This is the time between the client disconnect and the time the will message will be sent.
+        ///     Gets the will delay interval.
+        ///     This is the time between the client disconnect and the time the will message will be sent.
         /// </summary>
-        uint? WillDelayInterval { get; set; }
+        public uint? WillDelayInterval { get; set; }
 
-        DateTime? SessionExpiryTimestamp { get; set; }
+        // <summary>
+        //     Gets the last will message.
+        //     In MQTT, you use the last will message feature to notify other clients about an ungracefully disconnected client.
+        // </summary>
+        // TODO: Use single properties. No entire will message.
+        //MqttApplicationMessage WillMessage { get; set; }
     }
 }

Source/MQTTnet/Server/Internal/ISubscriptionChangedNotification.cs

@@ -1,13 +1,11 @@
-using System;
 using System.Collections.Generic;
-using System.Text;
 
 namespace MQTTnet.Server
 {
     public interface ISubscriptionChangedNotification
     {
         void OnSubscriptionsAdded(MqttSession clientSession, List<string> subscriptionsTopics);
-        
+
         void OnSubscriptionsRemoved(MqttSession clientSession, List<string> subscriptionTopics);
     }
-}
+}

Source/MQTTnet/Server/Internal/MqttClient.cs

@@ -103,24 +103,24 @@ namespace MQTTnet.Server
             Session.LatestConnectPacket = _connectPacket;
             Session.WillMessageSent = false;
 
-            using (var cancellationToken = new CancellationTokenSource())
+            using (_cancellationToken = new CancellationTokenSource())
             {
-                _cancellationToken = cancellationToken;
+                var cancellationToken = _cancellationToken.Token;
 
                 try
                 {
-                    Task.Run(() => SendPacketsLoop(cancellationToken.Token), cancellationToken.Token).RunInBackground(_logger);
+                    Task.Run(() => SendPacketsLoop(cancellationToken), cancellationToken).RunInBackground(_logger);
                     
                     IsRunning = true;
 
-                    await ReceivePackagesLoop(cancellationToken.Token).ConfigureAwait(false);
+                    await ReceivePackagesLoop(cancellationToken).ConfigureAwait(false);
                 }
                 finally
                 {
                     IsRunning = false;
 
+                    _cancellationToken?.Cancel();
                     _cancellationToken = null;
-                    cancellationToken.Cancel();
                 }
             }
 

Source/MQTTnet/Server/MqttServerExtensions.cs

@@ -2,9 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using MQTTnet.Protocol;
 using System;
-using System.Threading;
 using System.Threading.Tasks;
 using MQTTnet.Packets;