Add support for reset of connection statistics. Refactor keep alive monitor.

Source/MQTTnet.AspnetCore/MqttConnectionContext.cs

@@ -145,6 +145,12 @@ namespace MQTTnet.AspNetCore
             return null;
         }
 
+        public void ResetStatistics()
+        {
+            BytesReceived = 0;
+            BytesSent = 0;
+        }
+
         public async Task SendPacketAsync(MqttBasePacket packet, TimeSpan timeout, CancellationToken cancellationToken)
         {
             var formatter = PacketFormatterAdapter;

Source/MQTTnet/Adapter/IMqttChannelAdapter.cs

@@ -32,5 +32,7 @@ namespace MQTTnet.Adapter
         Task SendPacketAsync(MqttBasePacket packet, TimeSpan timeout, CancellationToken cancellationToken);
 
         Task<MqttBasePacket> ReceivePacketAsync(TimeSpan timeout, CancellationToken cancellationToken);
+
+        void ResetStatistics();
     }
 }

Source/MQTTnet/Server/MqttClientConnection.cs

@@ -14,7 +14,7 @@ using MQTTnet.Server.Status;
 
 namespace MQTTnet.Server
 {
-    public class MqttClientConnection : IMqttClientSession, IDisposable
+    public class MqttClientConnection : IDisposable
     {
         private readonly MqttPacketIdentifierProvider _packetIdentifierProvider = new MqttPacketIdentifierProvider();
         private readonly MqttPacketDispatcher _packetDispatcher = new MqttPacketDispatcher();
@@ -64,7 +64,7 @@ namespace MQTTnet.Server
             if (logger == null) throw new ArgumentNullException(nameof(logger));
             _logger = logger.CreateChildLogger(nameof(MqttClientConnection));
 
-            _keepAliveMonitor = new MqttClientKeepAliveMonitor(this, _logger);
+            _keepAliveMonitor = new MqttClientKeepAliveMonitor(_connectPacket.ClientId, StopAsync, _logger);
 
             _connectedTimestamp = DateTime.UtcNow;
             _lastPacketReceivedTimestamp = _connectedTimestamp;
@@ -86,6 +86,11 @@ namespace MQTTnet.Server
             }
         }
 
+        public void ResetStatistics()
+        {
+            _channelAdapter.ResetStatistics();
+        }
+
         public void FillStatus(MqttClientStatus status)
         {
             status.ClientId = ClientId;

Source/MQTTnet/Server/MqttClientKeepAliveMonitor.cs

@@ -10,17 +10,18 @@ namespace MQTTnet.Server
     {
         private readonly Stopwatch _lastPacketReceivedTracker = new Stopwatch();
 
-        private readonly IMqttClientSession _clientSession;
+        private readonly string _clientId;
+        private readonly Func<Task> _keepAliveElapsedCallback;
         private readonly IMqttNetChildLogger _logger;
 
         private bool _isPaused;
 
-        public MqttClientKeepAliveMonitor(IMqttClientSession clientSession, IMqttNetChildLogger logger)
+        public MqttClientKeepAliveMonitor(string clientId, Func<Task> keepAliveElapsedCallback, IMqttNetChildLogger logger)
         {
+            _clientId = clientId ?? throw new ArgumentNullException(nameof(clientId));
+            _keepAliveElapsedCallback = keepAliveElapsedCallback ?? throw new ArgumentNullException(nameof(keepAliveElapsedCallback));
+            
             if (logger == null) throw new ArgumentNullException(nameof(logger));
-
-            _clientSession = clientSession ?? throw new ArgumentNullException(nameof(clientSession));
-
             _logger = logger.CreateChildLogger(nameof(MqttClientKeepAliveMonitor));
         }
 
@@ -62,8 +63,8 @@ namespace MQTTnet.Server
                     // If the client sends 1 sec. the server will allow up to 1.5 seconds.
                     if (!_isPaused && _lastPacketReceivedTracker.Elapsed.TotalSeconds >= keepAlivePeriod * 1.5D)
                     {
-                        _logger.Warning(null, "Client '{0}': Did not receive any packet or keep alive signal.", _clientSession.ClientId);
-                        await _clientSession.StopAsync().ConfigureAwait(false);
+                        _logger.Warning(null, "Client '{0}': Did not receive any packet or keep alive signal.", _clientId);
+                        await _keepAliveElapsedCallback().ConfigureAwait(false);
 
                         return;
                     }
@@ -80,11 +81,11 @@ namespace MQTTnet.Server
             }
             catch (Exception exception)
             {
-                _logger.Error(exception, "Client '{0}': Unhandled exception while checking keep alive timeouts.", _clientSession.ClientId);
+                _logger.Error(exception, "Client '{0}': Unhandled exception while checking keep alive timeouts.", _clientId);
             }
             finally
             {
-                _logger.Verbose("Client '{0}': Stopped checking keep alive timeout.", _clientSession.ClientId);
+                _logger.Verbose("Client '{0}': Stopped checking keep alive timeout.", _clientId);
             }
         }
     }

Source/MQTTnet/Server/Status/IMqttClientStatus.cs

@@ -29,7 +29,9 @@ namespace MQTTnet.Server.Status
         long BytesSent { get; }
 
         long BytesReceived { get; }
-
+        
         Task DisconnectAsync();
+
+        void ResetStatistics();
     }
 }

Source/MQTTnet/Server/Status/MqttClientStatus.cs

@@ -43,5 +43,10 @@ namespace MQTTnet.Server.Status
         {
             return _connection.StopAsync();
         }
+
+        public void ResetStatistics()
+        {
+            _connection.ResetStatistics();
+        }
     }
 }

Tests/MQTTnet.Core.Tests/Mockups/TestMqttCommunicationAdapter.cs

@@ -69,6 +69,10 @@ namespace MQTTnet.Tests.Mockups
             }, cancellationToken);
         }
 
+        public void ResetStatistics()
+        {
+        }
+
         private void EnqueuePacketInternal(MqttBasePacket packet)
         {
             if (packet == null) throw new ArgumentNullException(nameof(packet));

Tests/MQTTnet.Core.Tests/MqttKeepAliveMonitor_Tests.cs

@@ -16,31 +16,43 @@ namespace MQTTnet.Tests
         [TestMethod]
         public void KeepAlive_Timeout()
         {
-            var clientSession = new TestClientSession();
-            var monitor = new MqttClientKeepAliveMonitor(clientSession, new MqttNetLogger().CreateChildLogger());
+            var counter = 0;
 
-            Assert.AreEqual(0, clientSession.StopCalledCount);
+            var monitor = new MqttClientKeepAliveMonitor("", () =>
+                {
+                    counter++;
+                    return Task.CompletedTask;
+                },
+                new MqttNetLogger().CreateChildLogger());
+
+            Assert.AreEqual(0, counter);
 
             monitor.Start(1, CancellationToken.None);
 
-            Assert.AreEqual(0, clientSession.StopCalledCount);
+            Assert.AreEqual(0, counter);
 
             Thread.Sleep(2000); // Internally the keep alive timeout is multiplied with 1.5 as per protocol specification.
 
-            Assert.AreEqual(1, clientSession.StopCalledCount);
+            Assert.AreEqual(1, counter);
         }
 
         [TestMethod]
         public void KeepAlive_NoTimeout()
         {
-            var clientSession = new TestClientSession();
-            var monitor = new MqttClientKeepAliveMonitor(clientSession, new MqttNetLogger().CreateChildLogger());
+            var counter = 0;
 
-            Assert.AreEqual(0, clientSession.StopCalledCount);
+            var monitor = new MqttClientKeepAliveMonitor("", () =>
+                {
+                    counter++;
+                    return Task.CompletedTask;
+                },
+                new MqttNetLogger().CreateChildLogger());
+
+            Assert.AreEqual(0, counter);
 
             monitor.Start(1, CancellationToken.None);
 
-            Assert.AreEqual(0, clientSession.StopCalledCount);
+            Assert.AreEqual(0, counter);
 
             // Simulate traffic.
             Thread.Sleep(1000); // Internally the keep alive timeout is multiplied with 1.5 as per protocol specification.
@@ -49,11 +61,11 @@ namespace MQTTnet.Tests
             monitor.PacketReceived();
             Thread.Sleep(1000);
 
-            Assert.AreEqual(0, clientSession.StopCalledCount);
+            Assert.AreEqual(0, counter);
 
             Thread.Sleep(2000);
 
-            Assert.AreEqual(1, clientSession.StopCalledCount);
+            Assert.AreEqual(1, counter);
         }
 
         private class TestClientSession : IMqttClientSession