Add interfaces, optimize performance, fix QoS level 2

Frameworks/MQTTnet.NetFramework/MqttClientFactory.cs

@@ -8,7 +8,7 @@ namespace MQTTnet
 {
     public class MqttClientFactory
     {
-        public MqttClient CreateMqttClient(MqttClientOptions options)
+        public IMqttClient CreateMqttClient(MqttClientOptions options)
         {
             if (options == null) throw new ArgumentNullException(nameof(options));
 

Frameworks/MQTTnet.NetFramework/MqttServerFactory.cs

@@ -8,7 +8,7 @@ namespace MQTTnet
 {
     public class MqttServerFactory
     {
-        public MqttServer CreateMqttServer(MqttServerOptions options)
+        public IMqttServer CreateMqttServer(MqttServerOptions options)
         {
             if (options == null) throw new ArgumentNullException(nameof(options));
 

Frameworks/MQTTnet.NetStandard/MqttClientFactory.cs

@@ -8,7 +8,7 @@ namespace MQTTnet
 {
     public class MqttClientFactory
     {
-        public MqttClient CreateMqttClient(MqttClientOptions options)
+        public IMqttClient CreateMqttClient(MqttClientOptions options)
         {
             if (options == null) throw new ArgumentNullException(nameof(options));
 

Frameworks/MQTTnet.NetStandard/MqttServerFactory.cs

@@ -8,7 +8,7 @@ namespace MQTTnet
 {
     public class MqttServerFactory
     {
-        public MqttServer CreateMqttServer(MqttServerOptions options)
+        public IMqttServer CreateMqttServer(MqttServerOptions options)
         {
             if (options == null) throw new ArgumentNullException(nameof(options));
 

Frameworks/MQTTnet.UniversalWindows/MqttClientFactory.cs

@@ -8,7 +8,7 @@ namespace MQTTnet
 {
     public class MqttClientFactory
     {
-        public MqttClient CreateMqttClient(MqttClientOptions options)
+        public IMqttClient CreateMqttClient(MqttClientOptions options)
         {
             if (options == null) throw new ArgumentNullException(nameof(options));
 

Frameworks/MQTTnet.UniversalWindows/MqttServerFactory.cs

@@ -8,7 +8,7 @@ namespace MQTTnet
 {
     public class MqttServerFactory
     {
-        public MqttServer CreateMqttServer(MqttServerOptions options)
+        public IMqttServer CreateMqttServer(MqttServerOptions options)
         {
             if (options == null) throw new ArgumentNullException(nameof(options));
 

MQTTnet.Core/Client/IMqttClient.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using MQTTnet.Core.Packets;
+
+namespace MQTTnet.Core.Client
+{
+    public interface IMqttClient
+    {
+        bool IsConnected { get; }
+
+        event EventHandler<MqttApplicationMessageReceivedEventArgs> ApplicationMessageReceived;
+        event EventHandler Connected;
+        event EventHandler Disconnected;
+
+        Task ConnectAsync(MqttApplicationMessage willApplicationMessage = null);
+        Task DisconnectAsync();
+        Task PublishAsync(MqttApplicationMessage applicationMessage);
+        Task<IList<MqttSubscribeResult>> SubscribeAsync(IList<TopicFilter> topicFilters);
+        Task<IList<MqttSubscribeResult>> SubscribeAsync(params TopicFilter[] topicFilters);
+        Task Unsubscribe(IList<string> topicFilters);
+        Task Unsubscribe(params string[] topicFilters);
+    }
+}

MQTTnet.Core/Client/MqttClient.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
@@ -13,10 +12,9 @@
 
 namespace MQTTnet.Core.Client
 {
-    public class MqttClient
+    public class MqttClient : IMqttClient
     {
-        private readonly ConcurrentDictionary<ushort, MqttPublishPacket> _pendingExactlyOncePublishPackets = new ConcurrentDictionary<ushort, MqttPublishPacket>();
-        private readonly HashSet<ushort> _processedPublishPackets = new HashSet<ushort>();
+        private readonly HashSet<ushort> _unacknowledgedPublishPackets = new HashSet<ushort>();
 
         private readonly MqttPacketDispatcher _packetDispatcher = new MqttPacketDispatcher();
         private readonly MqttClientOptions _options;
@@ -63,7 +61,6 @@ public async Task ConnectAsync(MqttApplicationMessage willApplicationMessage = n
 
             _cancellationTokenSource = new CancellationTokenSource();
             _latestPacketIdentifier = 0;
-            _processedPublishPackets.Clear();
             _packetDispatcher.Reset();
             IsConnected = true;
 
@@ -105,6 +102,7 @@ public async Task<IList<MqttSubscribeResult>> SubscribeAsync(IList<TopicFilter>
         {
             if (topicFilters == null) throw new ArgumentNullException(nameof(topicFilters));
             if (!topicFilters.Any()) throw new MqttProtocolViolationException("At least one topic filter must be set [MQTT-3.8.3-3].");
+
             ThrowIfNotConnected();
 
             var subscribePacket = new MqttSubscribePacket
@@ -154,6 +152,7 @@ public async Task PublishAsync(MqttApplicationMessage applicationMessage)
 
             if (publishPacket.QualityOfServiceLevel == MqttQualityOfServiceLevel.AtMostOnce)
             {
+                // No packet identifier is used for QoS 0 [3.3.2.2 Packet Identifier]
                 await SendAsync(publishPacket);
             }
             else if (publishPacket.QualityOfServiceLevel == MqttQualityOfServiceLevel.AtLeastOnce)
@@ -164,8 +163,8 @@ public async Task PublishAsync(MqttApplicationMessage applicationMessage)
             else if (publishPacket.QualityOfServiceLevel == MqttQualityOfServiceLevel.ExactlyOnce)
             {
                 publishPacket.PacketIdentifier = GetNewPacketIdentifier();
-                await SendAndReceiveAsync<MqttPubRecPacket>(publishPacket);
-                await SendAsync(publishPacket.CreateResponse<MqttPubCompPacket>());
+                var pubRecPacket = await SendAndReceiveAsync<MqttPubRecPacket>(publishPacket);
+                await SendAndReceiveAsync<MqttPubCompPacket>(pubRecPacket.CreateResponse<MqttPubRelPacket>());
             }
         }
 
@@ -208,14 +207,12 @@ private Task ProcessReceivedPacketAsync(MqttBasePacket mqttPacket)
                     return DisconnectAsync();
                 }
 
-                var publishPacket = mqttPacket as MqttPublishPacket;
-                if (publishPacket != null)
+                if (mqttPacket is MqttPublishPacket publishPacket)
                 {
                     return ProcessReceivedPublishPacket(publishPacket);
                 }
 
-                var pubRelPacket = mqttPacket as MqttPubRelPacket;
-                if (pubRelPacket != null)
+                if (mqttPacket is MqttPubRelPacket pubRelPacket)
                 {
                     return ProcessReceivedPubRelPacket(pubRelPacket);
                 }
@@ -232,11 +229,6 @@ private Task ProcessReceivedPacketAsync(MqttBasePacket mqttPacket)
 
         private void FireApplicationMessageReceivedEvent(MqttPublishPacket publishPacket)
         {
-            if (publishPacket.QualityOfServiceLevel != MqttQualityOfServiceLevel.AtMostOnce)
-            {
-                _processedPublishPackets.Add(publishPacket.PacketIdentifier);
-            }
-
             var applicationMessage = publishPacket.ToApplicationMessage();
 
             try
@@ -265,7 +257,13 @@ private Task ProcessReceivedPublishPacket(MqttPublishPacket publishPacket)
 
             if (publishPacket.QualityOfServiceLevel == MqttQualityOfServiceLevel.ExactlyOnce)
             {
-                _pendingExactlyOncePublishPackets[publishPacket.PacketIdentifier] = publishPacket;
+                // QoS 2 is implement as method "B" [4.3.3 QoS 2: Exactly once delivery]
+                lock (_unacknowledgedPublishPackets)
+                {
+                    _unacknowledgedPublishPackets.Add(publishPacket.PacketIdentifier);
+                }
+
+                FireApplicationMessageReceivedEvent(publishPacket);
                 return SendAsync(new MqttPubRecPacket { PacketIdentifier = publishPacket.PacketIdentifier });
             }
 
@@ -274,15 +272,12 @@ private Task ProcessReceivedPublishPacket(MqttPublishPacket publishPacket)
 
         private async Task ProcessReceivedPubRelPacket(MqttPubRelPacket pubRelPacket)
         {
-            MqttPublishPacket originalPublishPacket;
-            if (!_pendingExactlyOncePublishPackets.TryRemove(pubRelPacket.PacketIdentifier, out originalPublishPacket))
+            lock (_unacknowledgedPublishPackets)
             {
-                throw new MqttCommunicationException();
+                _unacknowledgedPublishPackets.Remove(pubRelPacket.PacketIdentifier);
             }
-
-            await SendAsync(originalPublishPacket.CreateResponse<MqttPubCompPacket>());
-
-            FireApplicationMessageReceivedEvent(originalPublishPacket);
+
+            await SendAsync(pubRelPacket.CreateResponse<MqttPubCompPacket>());
         }
 
         private Task SendAsync(MqttBasePacket packet)
@@ -300,8 +295,8 @@ bool ResponsePacketSelector(MqttBasePacket p)
                     return false;
                 }
 
-                var pi1 = requestPacket as IPacketWithIdentifier;
-                var pi2 = p as IPacketWithIdentifier;
+                var pi1 = requestPacket as IMqttPacketWithIdentifier;
+                var pi2 = p as IMqttPacketWithIdentifier;
 
                 if (pi1 != null && pi2 != null)
                 {

MQTTnet.Core/Packets/IPacketWithPacketIdentifier.cs → MQTTnet.Core/Packets/IMqttPacketWithIdentifier.cs

@@ -1,6 +1,6 @@
 namespace MQTTnet.Core.Packets
 {
-    public interface IPacketWithIdentifier
+    public interface IMqttPacketWithIdentifier
     {
         ushort PacketIdentifier { get; set; }
     }

MQTTnet.Core/Packets/MqttBasePacket.cs

@@ -1,25 +1,6 @@
-using System;
-
-namespace MQTTnet.Core.Packets
+namespace MQTTnet.Core.Packets
 {
     public abstract class MqttBasePacket
     {
-        public TResponsePacket CreateResponse<TResponsePacket>()
-        {
-            var responsePacket = Activator.CreateInstance<TResponsePacket>();
-            var responsePacketWithIdentifier = responsePacket as IPacketWithIdentifier;
-            if (responsePacketWithIdentifier != null)
-            {
-                var requestPacketWithIdentifier = this as IPacketWithIdentifier;
-                if (requestPacketWithIdentifier == null)
-                {
-                    throw new InvalidOperationException("Response packet has PacketIdentifier but request packet does not.");
-                }
-
-                responsePacketWithIdentifier.PacketIdentifier = requestPacketWithIdentifier.PacketIdentifier;
-            }
-
-            return responsePacket;
-        }
     }
 }

MQTTnet.Core/Packets/MqttBasePublishPacket.cs

@@ -1,6 +1,6 @@
 namespace MQTTnet.Core.Packets
 {
-    public class MqttBasePublishPacket : MqttBasePacket, IPacketWithIdentifier
+    public class MqttBasePublishPacket : MqttBasePacket, IMqttPacketWithIdentifier
     {
         public ushort PacketIdentifier { get; set; }
     }

MQTTnet.Core/Packets/MqttPacketExtensions.cs

@@ -0,0 +1,27 @@
+using System;
+
+namespace MQTTnet.Core.Packets
+{
+    public static class MqttPacketExtensions
+    {
+        public static TResponsePacket CreateResponse<TResponsePacket>(this MqttBasePacket packet)
+        {
+            if (packet == null) throw new ArgumentNullException(nameof(packet));
+
+            var responsePacket = Activator.CreateInstance<TResponsePacket>();
+
+            if (responsePacket is IMqttPacketWithIdentifier responsePacketWithIdentifier)
+            {
+                var requestPacketWithIdentifier = packet as IMqttPacketWithIdentifier;
+                if (requestPacketWithIdentifier == null)
+                {
+                    throw new InvalidOperationException("Response packet has PacketIdentifier but request packet does not.");
+                }
+
+                responsePacketWithIdentifier.PacketIdentifier = requestPacketWithIdentifier.PacketIdentifier;
+            }
+
+            return responsePacket;
+        }
+    }
+}

MQTTnet.Core/Packets/MqttSubAckPacket.cs

@@ -4,7 +4,7 @@
 
 namespace MQTTnet.Core.Packets
 {
-    public sealed class MqttSubAckPacket : MqttBasePacket, IPacketWithIdentifier
+    public sealed class MqttSubAckPacket : MqttBasePacket, IMqttPacketWithIdentifier
     {
         public ushort PacketIdentifier { get; set; }
 

MQTTnet.Core/Packets/MqttSubscribePacket.cs

@@ -3,7 +3,7 @@
 
 namespace MQTTnet.Core.Packets
 {
-    public sealed class MqttSubscribePacket : MqttBasePacket, IPacketWithIdentifier
+    public sealed class MqttSubscribePacket : MqttBasePacket, IMqttPacketWithIdentifier
     {
         public ushort PacketIdentifier { get; set; }
 

MQTTnet.Core/Packets/MqttUnsubAckPacket.cs

@@ -1,6 +1,6 @@
 namespace MQTTnet.Core.Packets
 {
-    public sealed class MqttUnsubAckPacket : MqttBasePacket, IPacketWithIdentifier
+    public sealed class MqttUnsubAckPacket : MqttBasePacket, IMqttPacketWithIdentifier
     {
         public ushort PacketIdentifier { get; set; }
     }

MQTTnet.Core/Packets/MqttUnsubscribe.cs

@@ -2,7 +2,7 @@
 
 namespace MQTTnet.Core.Packets
 {
-    public sealed class MqttUnsubscribePacket : MqttBasePacket, IPacketWithIdentifier
+    public sealed class MqttUnsubscribePacket : MqttBasePacket, IMqttPacketWithIdentifier
     {
         public ushort PacketIdentifier { get; set; }
 

MQTTnet.Core/Server/IMqttServer.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+using MQTTnet.Core.Adapter;
+
+namespace MQTTnet.Core.Server
+{
+    public interface IMqttServer
+    {
+        event EventHandler<MqttApplicationMessageReceivedEventArgs> ApplicationMessageReceived;
+        event EventHandler<MqttClientConnectedEventArgs> ClientConnected;
+
+        IList<string> GetConnectedClients();
+        void InjectClient(string identifier, IMqttCommunicationAdapter adapter);
+        void Publish(MqttApplicationMessage applicationMessage);
+        void Start();
+        void Stop();
+    }
+}

MQTTnet.Core/Server/MqttClientMessageQueue.cs

@@ -35,7 +35,7 @@ public void Start(IMqttCommunicationAdapter adapter)
             _adapter = adapter ?? throw new ArgumentNullException(nameof(adapter));
             _cancellationTokenSource = new CancellationTokenSource();
 
-            Task.Run(() => SendPendingPublishPacketsAsync(_cancellationTokenSource.Token));
+            Task.Run(() => SendPendingPublishPacketsAsync(_cancellationTokenSource.Token), _cancellationTokenSource.Token);
         }
 
         public void Stop()
@@ -45,14 +45,13 @@ public void Stop()
             _cancellationTokenSource = null;
         }
 
-        public void Enqueue(MqttClientSession senderClientSession, MqttPublishPacket publishPacket)
+        public void Enqueue(MqttPublishPacket publishPacket)
         {
-            if (senderClientSession == null) throw new ArgumentNullException(nameof(senderClientSession));
             if (publishPacket == null) throw new ArgumentNullException(nameof(publishPacket));
 
             lock (_pendingPublishPackets)
             {
-                _pendingPublishPackets.Add(new MqttClientPublishPacketContext(senderClientSession, publishPacket));
+                _pendingPublishPackets.Add(new MqttClientPublishPacketContext(publishPacket));
                 _gate.Set();
             }
         }

MQTTnet.Core/Server/MqttClientPublishPacketContext.cs

@@ -5,14 +5,11 @@ namespace MQTTnet.Core.Server
 {
     public sealed class MqttClientPublishPacketContext
     {
-        public MqttClientPublishPacketContext(MqttClientSession senderClientSession, MqttPublishPacket publishPacket)
+        public MqttClientPublishPacketContext(MqttPublishPacket publishPacket)
         {
-            SenderClientSession = senderClientSession ?? throw new ArgumentNullException(nameof(senderClientSession));
             PublishPacket = publishPacket ?? throw new ArgumentNullException(nameof(publishPacket));
         }
 
-        public MqttClientSession SenderClientSession { get; }
-
         public MqttPublishPacket PublishPacket { get; }
 
         public int SendTries { get; set; }