Refactor keep alive monitoring and add unit tests.

2026-10-18 10:26:11 +08:00 · 2018-02-28 21:43:19 +01:00
parent f5696b6fc0
commit f85ad4965b
8 changed files with 182 additions and 76 deletions
@@ -0,0 +1,88 @@
+using System;
+using System.Diagnostics;
+using System.Threading;
+using System.Threading.Tasks;
+using MQTTnet.Diagnostics;
+using MQTTnet.Packets;
+
+namespace MQTTnet.Server
+{
+    public sealed class MqttClientKeepAliveMonitor
+    {
+        private readonly Stopwatch _lastPacketReceivedTracker = new Stopwatch();
+        private readonly Stopwatch _lastNonKeepAlivePacketReceivedTracker = new Stopwatch();
+
+        private readonly string _clientId;
+        private readonly Func<Task> _timeoutCallback;
+        private readonly IMqttNetLogger _logger;
+
+        public MqttClientKeepAliveMonitor(string clientId, Func<Task> timeoutCallback, IMqttNetLogger logger)
+        {
+            _clientId = clientId;
+            _timeoutCallback = timeoutCallback;
+            _logger = logger;
+        }
+
+        public TimeSpan LastPacketReceived => _lastPacketReceivedTracker.Elapsed;
+
+        public TimeSpan LastNonKeepAlivePacketReceived => _lastNonKeepAlivePacketReceivedTracker.Elapsed;
+
+        public void Start(int keepAlivePeriod, CancellationToken cancellationToken)
+        {
+            if (keepAlivePeriod == 0)
+            {
+                return;
+            }
+
+            Task.Run(async () => await RunAsync(keepAlivePeriod, cancellationToken).ConfigureAwait(false), cancellationToken).ConfigureAwait(false);
+        }
+
+        private async Task RunAsync(int keepAlivePeriod, CancellationToken cancellationToken)
+        {
+            try
+            {
+                _lastPacketReceivedTracker.Restart();
+                _lastNonKeepAlivePacketReceivedTracker.Restart();
+
+                while (!cancellationToken.IsCancellationRequested)
+                {
+                    // Values described here: [MQTT-3.1.2-24].
+                    if (_lastPacketReceivedTracker.Elapsed.TotalSeconds > keepAlivePeriod * 1.5D)
+                    {
+                        _logger.Warning<MqttClientSession>("Client '{0}': Did not receive any packet or keep alive signal.", _clientId);
+
+                        if (_timeoutCallback != null)
+                        {
+                            await _timeoutCallback().ConfigureAwait(false);
+                        }
+
+                        return;
+                    }
+
+                    await Task.Delay(keepAlivePeriod, cancellationToken).ConfigureAwait(false);
+                }
+            }
+            catch (OperationCanceledException)
+            {
+            }
+            catch (Exception exception)
+            {
+                _logger.Error<MqttClientSession>(exception, "Client '{0}': Unhandled exception while checking keep alive timeouts.", _clientId);
+            }
+            finally
+            {
+                _logger.Trace<MqttClientSession>("Client {0}: Stopped checking keep alive timeout.", _clientId);
+            }
+        }
+
+        public void PacketReceived(MqttBasePacket packet)
+        {
+            _lastPacketReceivedTracker.Restart();
+
+            if (!(packet is MqttPingReqPacket))
+            {
+                _lastNonKeepAlivePacketReceivedTracker.Restart();
+            }
+        }
+    }
+}