Restore SEBPatch

SafeExamBrowser.Proctoring/ScreenProctoring/DataCollector.cs

@@ -0,0 +1,177 @@
+/*
+ * Copyright (c) 2024 ETH Zürich, IT Services
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using System.Timers;
+using System.Windows.Input;
+using SafeExamBrowser.Browser.Contracts;
+using SafeExamBrowser.Logging.Contracts;
+using SafeExamBrowser.Monitoring.Contracts.Applications;
+using SafeExamBrowser.Proctoring.ScreenProctoring.Data;
+using SafeExamBrowser.Proctoring.ScreenProctoring.Events;
+using SafeExamBrowser.Proctoring.ScreenProctoring.Imaging;
+using SafeExamBrowser.Settings.Proctoring;
+using SafeExamBrowser.WindowsApi.Contracts;
+using SafeExamBrowser.WindowsApi.Contracts.Events;
+using MouseButton = SafeExamBrowser.WindowsApi.Contracts.Events.MouseButton;
+using MouseButtonState = SafeExamBrowser.WindowsApi.Contracts.Events.MouseButtonState;
+using Timer = System.Timers.Timer;
+
+namespace SafeExamBrowser.Proctoring.ScreenProctoring
+{
+	internal class DataCollector
+	{
+		private readonly object @lock = new object();
+
+		private readonly IApplicationMonitor applicationMonitor;
+		private readonly IBrowserApplication browser;
+		private readonly IModuleLogger logger;
+		private readonly INativeMethods nativeMethods;
+		private readonly ScreenProctoringSettings settings;
+		private readonly Timer timer;
+
+		private DateTime last;
+		private Guid? keyboardHookId;
+		private Guid? mouseHookId;
+
+		internal event DataCollectedEventHandler DataCollected;
+
+		internal DataCollector(
+			IApplicationMonitor applicationMonitor,
+			IBrowserApplication browser,
+			IModuleLogger logger,
+			INativeMethods nativeMethods,
+			ScreenProctoringSettings settings)
+		{
+			this.applicationMonitor = applicationMonitor;
+			this.browser = browser;
+			this.logger = logger;
+			this.nativeMethods = nativeMethods;
+			this.settings = settings;
+			this.timer = new Timer();
+		}
+
+		internal void Start()
+		{
+			last = DateTime.Now;
+
+			keyboardHookId = nativeMethods.RegisterKeyboardHook(KeyboardHookCallback);
+			mouseHookId = nativeMethods.RegisterMouseHook(MouseHookCallback);
+
+			timer.AutoReset = false;
+			timer.Elapsed += MaxIntervalElapsed;
+			timer.Interval = settings.MaxInterval;
+			timer.Start();
+
+			logger.Debug("Started.");
+		}
+
+		internal void Stop()
+		{
+			last = DateTime.Now;
+
+			if (keyboardHookId.HasValue)
+			{
+				nativeMethods.DeregisterKeyboardHook(keyboardHookId.Value);
+			}
+
+			if (mouseHookId.HasValue)
+			{
+				nativeMethods.DeregisterMouseHook(mouseHookId.Value);
+			}
+
+			keyboardHookId = default;
+			mouseHookId = default;
+
+			timer.Elapsed -= MaxIntervalElapsed;
+			timer.Stop();
+
+			logger.Debug("Stopped.");
+		}
+
+		private bool KeyboardHookCallback(int keyCode, KeyModifier modifier, KeyState state)
+		{
+			var trigger = new KeyboardTrigger
+			{
+				Key = KeyInterop.KeyFromVirtualKey(keyCode),
+				Modifier = modifier,
+				State = state
+			};
+
+			TryCollect(keyboard: trigger);
+
+			return false;
+		}
+
+		private void MaxIntervalElapsed(object sender, ElapsedEventArgs args)
+		{
+			var trigger = new IntervalTrigger
+			{
+				ConfigurationValue = settings.MaxInterval,
+			};
+
+			TryCollect(interval: trigger);
+		}
+
+		private bool MouseHookCallback(MouseButton button, MouseButtonState state, MouseInformation info)
+		{
+			var trigger = new MouseTrigger
+			{
+				Button = button,
+				Info = info,
+				State = state
+			};
+
+			TryCollect(mouse: trigger);
+
+			return false;
+		}
+
+		private void TryCollect(IntervalTrigger interval = default, KeyboardTrigger keyboard = default, MouseTrigger mouse = default)
+		{
+			if (MinIntervalElapsed() && Monitor.TryEnter(@lock))
+			{
+				var elapsed = DateTime.Now.Subtract(last);
+
+				last = DateTime.Now;
+				timer.Stop();
+
+				Task.Run(() =>
+				{
+					try
+					{
+						var metaData = new MetaDataAggregator(applicationMonitor, browser, elapsed, logger.CloneFor(nameof(MetaDataAggregator)), settings.MetaData);
+						var screenShot = new ScreenShotProcessor(logger.CloneFor(nameof(ScreenShotProcessor)), settings);
+
+						metaData.Capture(interval, keyboard, mouse);
+						screenShot.Take();
+						screenShot.Compress();
+
+						DataCollected?.Invoke(metaData.Data, screenShot.Data);
+
+						screenShot.Dispose();
+					}
+					catch (Exception e)
+					{
+						logger.Error("Failed to execute data collection!", e);
+					}
+				});
+
+				timer.Start();
+				Monitor.Exit(@lock);
+			}
+		}
+
+		private bool MinIntervalElapsed()
+		{
+			return DateTime.Now.Subtract(last) >= new TimeSpan(0, 0, 0, 0, settings.MinInterval);
+		}
+	}
+}