Migrate events in server to async handlers.

Source/MQTTnet/Server/IMqttServer.cs

@@ -10,9 +10,16 @@ namespace MQTTnet.Server
         event EventHandler Started;
         event EventHandler Stopped;
 
-        event EventHandler<MqttClientConnectedEventArgs> ClientConnected;
+        IMqttServerClientConnectedHandler ClientConnectedHandler { get; set; }
-        event EventHandler<MqttClientDisconnectedEventArgs> ClientDisconnected;
+        [Obsolete("Use ClientConnectedHandler instead.")]
+        event EventHandler<MqttServerClientConnectedEventArgs> ClientConnected;
+
+        IMqttServerClientDisconnectedHandler ClientDisconnectedHandler { get; set; }
+        [Obsolete("Use ClientDisconnectedHandler instead.")]
+        event EventHandler<MqttServerClientDisconnectedEventArgs> ClientDisconnected;
+
         event EventHandler<MqttClientSubscribedTopicEventArgs> ClientSubscribedTopic;
+
         event EventHandler<MqttClientUnsubscribedTopicEventArgs> ClientUnsubscribedTopic;
         
         IMqttServerOptions Options { get; }

Source/MQTTnet/Server/IMqttServerClientConnectedHandler.cs

@@ -0,0 +1,9 @@
+using System.Threading.Tasks;
+
+namespace MQTTnet.Server
+{
+    public interface IMqttServerClientConnectedHandler
+    {
+        Task HandleClientConnectedAsync(MqttServerClientConnectedEventArgs eventArgs);
+    }
+}

Source/MQTTnet/Server/IMqttServerClientDisconnectedHandler.cs

@@ -0,0 +1,9 @@
+using System.Threading.Tasks;
+
+namespace MQTTnet.Server
+{
+    public interface IMqttServerClientDisconnectedHandler
+    {
+        Task HandleClientDisconnectedAsync(MqttServerClientDisconnectedEventArgs eventArgs);
+    }
+}

Source/MQTTnet/Server/IMqttServerFactory.cs

@@ -10,6 +10,8 @@ namespace MQTTnet.Server
 
         IMqttServer CreateMqttServer(IMqttNetLogger logger);
 
+        IMqttServer CreateMqttServer(IEnumerable<IMqttServerAdapter> adapters);
+
         IMqttServer CreateMqttServer(IEnumerable<IMqttServerAdapter> adapters, IMqttNetLogger logger);
     }
 }

Source/MQTTnet/Server/MqttClientConnection.cs

@@ -14,62 +14,6 @@ using MQTTnet.Server.Status;
 
 namespace MQTTnet.Server
 {
-    public class MqttClientSession
-    {
-        private readonly DateTime _createdTimestamp = DateTime.UtcNow;
-
-        public MqttClientSession(string clientId, MqttServerEventDispatcher eventDispatcher, IMqttServerOptions serverOptions)
-        {
-            ClientId = clientId ?? throw new ArgumentNullException(nameof(clientId));
-
-            SubscriptionsManager = new MqttClientSubscriptionsManager(clientId, eventDispatcher, serverOptions);
-            ApplicationMessagesQueue = new MqttClientSessionApplicationMessagesQueue(serverOptions);
-        }
-
-        public string ClientId { get; }
-
-        public bool IsCleanSession { get; set; } = true;
-
-        public MqttApplicationMessage WillMessage { get; set; }
-
-        public MqttClientSubscriptionsManager SubscriptionsManager { get; }
-
-        public MqttClientSessionApplicationMessagesQueue ApplicationMessagesQueue { get; }
-
-        public void EnqueueApplicationMessage(MqttApplicationMessage applicationMessage, string senderClientId, bool isRetainedApplicationMessage)
-        {
-            var checkSubscriptionsResult = SubscriptionsManager.CheckSubscriptions(applicationMessage.Topic, applicationMessage.QualityOfServiceLevel);
-            if (!checkSubscriptionsResult.IsSubscribed)
-            {
-                return;
-            }
-
-            ApplicationMessagesQueue.Enqueue(applicationMessage, senderClientId, checkSubscriptionsResult.QualityOfServiceLevel, isRetainedApplicationMessage);
-        }
-
-        public async Task SubscribeAsync(ICollection<TopicFilter> topicFilters, MqttRetainedMessagesManager retainedMessagesManager)
-        {
-            await SubscriptionsManager.SubscribeAsync(topicFilters).ConfigureAwait(false);
-            var matchingRetainedMessages = await retainedMessagesManager.GetSubscribedMessagesAsync(topicFilters).ConfigureAwait(false);
-            foreach (var matchingRetainedMessage in matchingRetainedMessages)
-            {
-                EnqueueApplicationMessage(matchingRetainedMessage, null, true);
-            }
-        }
-
-        public Task UnsubscribeAsync(IEnumerable<string> topicFilters)
-        {
-            return SubscriptionsManager.UnsubscribeAsync(topicFilters);
-        }
-
-        public void FillStatus(MqttSessionStatus status)
-        {
-            status.ClientId = ClientId;
-            status.CreatedTimestamp = _createdTimestamp;
-            status.PendingApplicationMessagesCount = ApplicationMessagesQueue.Count;
-        }
-    }
-
     public class MqttClientConnection : IMqttClientSession, IDisposable
     {
         private readonly MqttPacketIdentifierProvider _packetIdentifierProvider = new MqttPacketIdentifierProvider();

Source/MQTTnet/Server/MqttClientSession.cs

@@ -0,0 +1,63 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using MQTTnet.Server.Status;
+
+namespace MQTTnet.Server
+{
+    public class MqttClientSession
+    {
+        private readonly DateTime _createdTimestamp = DateTime.UtcNow;
+
+        public MqttClientSession(string clientId, MqttServerEventDispatcher eventDispatcher, IMqttServerOptions serverOptions)
+        {
+            ClientId = clientId ?? throw new ArgumentNullException(nameof(clientId));
+
+            SubscriptionsManager = new MqttClientSubscriptionsManager(clientId, eventDispatcher, serverOptions);
+            ApplicationMessagesQueue = new MqttClientSessionApplicationMessagesQueue(serverOptions);
+        }
+
+        public string ClientId { get; }
+
+        public bool IsCleanSession { get; set; } = true;
+
+        public MqttApplicationMessage WillMessage { get; set; }
+
+        public MqttClientSubscriptionsManager SubscriptionsManager { get; }
+
+        public MqttClientSessionApplicationMessagesQueue ApplicationMessagesQueue { get; }
+
+        public void EnqueueApplicationMessage(MqttApplicationMessage applicationMessage, string senderClientId, bool isRetainedApplicationMessage)
+        {
+            var checkSubscriptionsResult = SubscriptionsManager.CheckSubscriptions(applicationMessage.Topic, applicationMessage.QualityOfServiceLevel);
+            if (!checkSubscriptionsResult.IsSubscribed)
+            {
+                return;
+            }
+
+            ApplicationMessagesQueue.Enqueue(applicationMessage, senderClientId, checkSubscriptionsResult.QualityOfServiceLevel, isRetainedApplicationMessage);
+        }
+
+        public async Task SubscribeAsync(ICollection<TopicFilter> topicFilters, MqttRetainedMessagesManager retainedMessagesManager)
+        {
+            await SubscriptionsManager.SubscribeAsync(topicFilters).ConfigureAwait(false);
+            var matchingRetainedMessages = await retainedMessagesManager.GetSubscribedMessagesAsync(topicFilters).ConfigureAwait(false);
+            foreach (var matchingRetainedMessage in matchingRetainedMessages)
+            {
+                EnqueueApplicationMessage(matchingRetainedMessage, null, true);
+            }
+        }
+
+        public Task UnsubscribeAsync(IEnumerable<string> topicFilters)
+        {
+            return SubscriptionsManager.UnsubscribeAsync(topicFilters);
+        }
+
+        public void FillStatus(MqttSessionStatus status)
+        {
+            status.ClientId = ClientId;
+            status.CreatedTimestamp = _createdTimestamp;
+            status.PendingApplicationMessagesCount = ApplicationMessagesQueue.Count;
+        }
+    }
+}

Source/MQTTnet/Server/MqttServer.cs

@@ -50,9 +50,14 @@ namespace MQTTnet.Server
         public event EventHandler Started;
         public event EventHandler Stopped;
 
-        public event EventHandler<MqttClientConnectedEventArgs> ClientConnected;
+        public IMqttServerClientConnectedHandler ClientConnectedHandler { get; set; }
-        public event EventHandler<MqttClientDisconnectedEventArgs> ClientDisconnected;
+        public event EventHandler<MqttServerClientConnectedEventArgs> ClientConnected;
+
+        public IMqttServerClientDisconnectedHandler ClientDisconnectedHandler { get; set; }
+        public event EventHandler<MqttServerClientDisconnectedEventArgs> ClientDisconnected;
+
         public event EventHandler<MqttClientSubscribedTopicEventArgs> ClientSubscribedTopic;
+
         public event EventHandler<MqttClientUnsubscribedTopicEventArgs> ClientUnsubscribedTopic;
 
         public IMqttApplicationMessageHandler ReceivedApplicationMessageHandler { get; set; }

Source/MQTTnet/Server/MqttServerClientConnectedEventArgs.cs

@@ -2,9 +2,9 @@
 
 namespace MQTTnet.Server
 {
-    public class MqttClientConnectedEventArgs : EventArgs
+    public class MqttServerClientConnectedEventArgs : EventArgs
     {
-        public MqttClientConnectedEventArgs(string clientId)
+        public MqttServerClientConnectedEventArgs(string clientId)
         {
             ClientId = clientId ?? throw new ArgumentNullException(nameof(clientId));
         }

Source/MQTTnet/Server/MqttServerClientConnectedHandlerDelegate.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Threading.Tasks;
+
+namespace MQTTnet.Server
+{
+    public class MqttServerClientConnectedHandlerDelegate : IMqttServerClientConnectedHandler
+    {
+        private readonly Func<MqttServerClientConnectedEventArgs, Task> _handler;
+
+        public MqttServerClientConnectedHandlerDelegate(Action<MqttServerClientConnectedEventArgs> handler)
+        {
+            if (handler == null) throw new ArgumentNullException(nameof(handler));
+
+            _handler = context =>
+            {
+                handler(context);
+                return Task.FromResult(0);
+            };
+        }
+
+        public MqttServerClientConnectedHandlerDelegate(Func<MqttServerClientConnectedEventArgs, Task> handler)
+        {
+            _handler = handler ?? throw new ArgumentNullException(nameof(handler));
+        }
+
+        public Task HandleClientConnectedAsync(MqttServerClientConnectedEventArgs eventArgs)
+        {
+            return _handler(eventArgs);
+        }
+    }
+}

Source/MQTTnet/Server/MqttServerClientDisconnectedEventArgs.cs

@@ -2,9 +2,9 @@
 
 namespace MQTTnet.Server
 {
-    public class MqttClientDisconnectedEventArgs : EventArgs
+    public class MqttServerClientDisconnectedEventArgs : EventArgs
     {
-        public MqttClientDisconnectedEventArgs(string clientId, MqttClientDisconnectType disconnectType)
+        public MqttServerClientDisconnectedEventArgs(string clientId, MqttClientDisconnectType disconnectType)
         {
             ClientId = clientId ?? throw new ArgumentNullException(nameof(clientId));
             DisconnectType = disconnectType;

Source/MQTTnet/Server/MqttServerClientDisconnectedHandlerDelegate.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Threading.Tasks;
+
+namespace MQTTnet.Server
+{
+    public class MqttServerClientDisconnectedHandlerDelegate : IMqttServerClientDisconnectedHandler
+    {
+        private readonly Func<MqttServerClientDisconnectedEventArgs, Task> _handler;
+
+        public MqttServerClientDisconnectedHandlerDelegate(Action<MqttServerClientDisconnectedEventArgs> handler)
+        {
+            if (handler == null) throw new ArgumentNullException(nameof(handler));
+
+            _handler = context =>
+            {
+                handler(context);
+                return Task.FromResult(0);
+            };
+        }
+
+        public MqttServerClientDisconnectedHandlerDelegate(Func<MqttServerClientDisconnectedEventArgs, Task> handler)
+        {
+            _handler = handler ?? throw new ArgumentNullException(nameof(handler));
+        }
+
+        public Task HandleClientDisconnectedAsync(MqttServerClientDisconnectedEventArgs eventArgs)
+        {
+            return _handler(eventArgs);
+        }
+    }
+}

Source/MQTTnet/Server/MqttServerEventDispatcher.cs

@@ -8,9 +8,9 @@ namespace MQTTnet.Server
 
         public event EventHandler<MqttClientUnsubscribedTopicEventArgs> ClientUnsubscribedTopic;
 
-        public event EventHandler<MqttClientConnectedEventArgs> ClientConnected;
+        public event EventHandler<MqttServerClientConnectedEventArgs> ClientConnected;
 
-        public event EventHandler<MqttClientDisconnectedEventArgs> ClientDisconnected;
+        public event EventHandler<MqttServerClientDisconnectedEventArgs> ClientDisconnected;
 
         public event EventHandler<MqttApplicationMessageReceivedEventArgs> ApplicationMessageReceived;
 
@@ -26,7 +26,7 @@ namespace MQTTnet.Server
 
         public void OnClientDisconnected(string clientId, MqttClientDisconnectType disconnectType)
         {
-            ClientDisconnected?.Invoke(this, new MqttClientDisconnectedEventArgs(clientId, disconnectType));
+            ClientDisconnected?.Invoke(this, new MqttServerClientDisconnectedEventArgs(clientId, disconnectType));
         }
 
         public void OnApplicationMessageReceived(string senderClientId, MqttApplicationMessage applicationMessage)
@@ -36,7 +36,7 @@ namespace MQTTnet.Server
 
         public void OnClientConnected(string clientId)
         {
-            ClientConnected?.Invoke(this, new MqttClientConnectedEventArgs(clientId));
+            ClientConnected?.Invoke(this, new MqttServerClientConnectedEventArgs(clientId));
         }
     }
 }