SEBSP-26: Implemented capturing and transmission interval.

SafeExamBrowser.Client/CompositionRoot.cs

@@ -288,7 +288,7 @@ namespace SafeExamBrowser.Client
 
 		private IOperation BuildProctoringOperation()
 		{
-			var controller = new ProctoringController(context.AppConfig, new FileSystem(), ModuleLogger(nameof(ProctoringController)), context.Server, text, uiFactory);
+			var controller = new ProctoringController(context.AppConfig, new FileSystem(), ModuleLogger(nameof(ProctoringController)), nativeMethods, context.Server, text, uiFactory);
 			var operation = new ProctoringOperation(actionCenter, context, controller, logger, taskbar, uiFactory);
 
 			return operation;

SafeExamBrowser.Configuration/ConfigurationData/DataMapping/ProctoringDataMapper.cs

@@ -90,6 +90,9 @@ namespace SafeExamBrowser.Configuration.ConfigurationData.DataMapping
 				case Keys.Proctoring.ScreenProctoring.ClientSecret:
 					MapClientSecret(settings, value);
 					break;
+				case Keys.Proctoring.ScreenProctoring.Enabled:
+					MapScreenProctoringEnabled(settings, value);
+					break;
 				case Keys.Proctoring.ScreenProctoring.GroupId:
 					MapGroupId(settings, value);
 					break;
@@ -108,9 +111,6 @@ namespace SafeExamBrowser.Configuration.ConfigurationData.DataMapping
 				case Keys.Proctoring.ScreenProctoring.MinInterval:
 					MapMinInterval(settings, value);
 					break;
-				case Keys.Proctoring.ScreenProctoring.Enabled:
-					MapScreenProctoringEnabled(settings, value);
-					break;
 				case Keys.Proctoring.ScreenProctoring.ServiceUrl:
 					MapServiceUrl(settings, value);
 					break;

SafeExamBrowser.Proctoring/ProctoringController.cs

@@ -19,6 +19,7 @@ using SafeExamBrowser.Server.Contracts.Events.Proctoring;
 using SafeExamBrowser.Settings.Proctoring;
 using SafeExamBrowser.SystemComponents.Contracts;
 using SafeExamBrowser.UserInterface.Contracts;
+using SafeExamBrowser.WindowsApi.Contracts;
 
 namespace SafeExamBrowser.Proctoring
 {
@@ -40,6 +41,7 @@ namespace SafeExamBrowser.Proctoring
 			AppConfig appConfig,
 			IFileSystem fileSystem,
 			IModuleLogger logger,
+			INativeMethods nativeMethods,
 			IServerProxy server,
 			IText text,
 			IUserInterfaceFactory uiFactory)
@@ -47,7 +49,7 @@ namespace SafeExamBrowser.Proctoring
 			this.logger = logger;
 			this.server = server;
 
-			factory = new ProctoringFactory(appConfig, fileSystem, logger, text, uiFactory);
+			factory = new ProctoringFactory(appConfig, fileSystem, logger, nativeMethods, text, uiFactory);
 			implementations = new List<ProctoringImplementation>();
 		}
 

SafeExamBrowser.Proctoring/ProctoringFactory.cs

@@ -16,6 +16,7 @@ using SafeExamBrowser.Proctoring.ScreenProctoring.Service;
 using SafeExamBrowser.Settings.Proctoring;
 using SafeExamBrowser.SystemComponents.Contracts;
 using SafeExamBrowser.UserInterface.Contracts;
+using SafeExamBrowser.WindowsApi.Contracts;
 
 namespace SafeExamBrowser.Proctoring
 {
@@ -24,14 +25,22 @@ namespace SafeExamBrowser.Proctoring
 		private readonly AppConfig appConfig;
 		private readonly IFileSystem fileSystem;
 		private readonly IModuleLogger logger;
+		private readonly INativeMethods nativeMethods;
 		private readonly IText text;
 		private readonly IUserInterfaceFactory uiFactory;
 
-		public ProctoringFactory(AppConfig appConfig, IFileSystem fileSystem, IModuleLogger logger, IText text, IUserInterfaceFactory uiFactory)
+		public ProctoringFactory(
+			AppConfig appConfig,
+			IFileSystem fileSystem,
+			IModuleLogger logger,
+			INativeMethods nativeMethods,
+			IText text,
+			IUserInterfaceFactory uiFactory)
 		{
 			this.appConfig = appConfig;
 			this.fileSystem = fileSystem;
 			this.logger = logger;
+			this.nativeMethods = nativeMethods;
 			this.text = text;
 			this.uiFactory = uiFactory;
 		}
@@ -52,7 +61,7 @@ namespace SafeExamBrowser.Proctoring
 				var logger = this.logger.CloneFor(nameof(ScreenProctoring));
 				var service = new ServiceProxy(logger.CloneFor(nameof(ServiceProxy)));
 
-				implementations.Add(new ScreenProctoringImplementation(logger, service, settings, text));
+				implementations.Add(new ScreenProctoringImplementation(logger, nativeMethods, service, settings, text));
 			}
 
 			return implementations;

SafeExamBrowser.Proctoring/SafeExamBrowser.Proctoring.csproj

@@ -145,6 +145,10 @@
       <Project>{c7889e97-6ff6-4a58-b7cb-521ed276b316}</Project>
       <Name>SafeExamBrowser.UserInterface.Contracts</Name>
     </ProjectReference>
+    <ProjectReference Include="..\SafeExamBrowser.WindowsApi.Contracts\SafeExamBrowser.WindowsApi.Contracts.csproj">
+      <Project>{7016F080-9AA5-41B2-A225-385AD877C171}</Project>
+      <Name>SafeExamBrowser.WindowsApi.Contracts</Name>
+    </ProjectReference>
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="JitsiMeet\index.html" />

SafeExamBrowser.Proctoring/ScreenProctoring/Imaging/ScreenShot.cs

@@ -46,12 +46,12 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring.Imaging
 
 		public string ToReducedString()
 		{
-			return $"{Width}x{Height}, {Data.Length / 1000:N0} kB, {Format.ToString().ToUpper()}";
+			return $"{Width}x{Height}, {Data.Length / 1000:N0}kB, {Format.ToString().ToUpper()}";
 		}
 
 		public override string ToString()
 		{
-			return $"resolution: {Width}x{Height}, size: {Data.Length / 1000:N0} kB, format: {Format.ToString().ToUpper()}";
+			return $"resolution: {Width}x{Height}, size: {Data.Length / 1000:N0}kB, format: {Format.ToString().ToUpper()}";
 		}
 
 		internal void Compress()

SafeExamBrowser.Proctoring/ScreenProctoring/ScreenProctoringImplementation.cs

@@ -7,7 +7,10 @@
  */
 
 using System;
+using System.Threading;
+using System.Threading.Tasks;
 using System.Timers;
+using System.Windows.Input;
 using SafeExamBrowser.Core.Contracts.Notifications.Events;
 using SafeExamBrowser.Core.Contracts.Resources.Icons;
 using SafeExamBrowser.I18n.Contracts;
@@ -16,24 +19,42 @@ using SafeExamBrowser.Proctoring.ScreenProctoring.Imaging;
 using SafeExamBrowser.Proctoring.ScreenProctoring.Service;
 using SafeExamBrowser.Server.Contracts.Events.Proctoring;
 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 ScreenProctoringImplementation : ProctoringImplementation
 	{
+		private readonly object @lock = new object();
+
 		private readonly IModuleLogger logger;
+		private readonly INativeMethods nativeMethods;
 		private readonly ServiceProxy service;
 		private readonly ScreenProctoringSettings settings;
 		private readonly IText text;
 		private readonly Timer timer;
 
+		private DateTime last;
+		private Guid? keyboardHookId;
+		private Guid? mouseHookId;
+
 		internal override string Name => nameof(ScreenProctoring);
 
 		public override event NotificationChangedEventHandler NotificationChanged;
 
-		internal ScreenProctoringImplementation(IModuleLogger logger, ServiceProxy service, ProctoringSettings settings, IText text)
+		internal ScreenProctoringImplementation(
+			IModuleLogger logger,
+			INativeMethods nativeMethods,
+			ServiceProxy service,
+			ProctoringSettings settings,
+			IText text)
 		{
 			this.logger = logger;
+			this.nativeMethods = nativeMethods;
 			this.service = service;
 			this.settings = settings.ScreenProctoring;
 			this.text = text;
@@ -62,7 +83,6 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 			else
 			{
 				ShowNotificationInactive();
-
 				logger.Info($"Initialized proctoring: Not all settings are valid or a server session is active, not starting automatically.");
 			}
 		}
@@ -96,9 +116,12 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 				logger.Info("Successfully processed instruction.");
 			}
 		}
-
 		internal override void Start()
 		{
+			last = DateTime.Now;
+			keyboardHookId = nativeMethods.RegisterKeyboardHook(KeyboardHookCallback);
+			mouseHookId = nativeMethods.RegisterMouseHook(MouseHookCallback);
+
 			timer.Elapsed += Timer_Elapsed;
 			timer.Start();
 
@@ -109,6 +132,19 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 
 		internal override void Stop()
 		{
+			if (keyboardHookId.HasValue)
+			{
+				nativeMethods.DeregisterKeyboardHook(keyboardHookId.Value);
+			}
+
+			if (mouseHookId.HasValue)
+			{
+				nativeMethods.DeregisterMouseHook(mouseHookId.Value);
+			}
+
+			keyboardHookId = default;
+			mouseHookId = default;
+
 			timer.Elapsed -= Timer_Elapsed;
 			timer.Stop();
 
@@ -120,11 +156,7 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 
 		internal override void Terminate()
 		{
-			if (timer.Enabled)
+			Stop();
-			{
-				Stop();
-			}
-
 			TerminateNotification();
 
 			logger.Info("Terminated proctoring.");
@@ -160,9 +192,28 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 			}
 		}
 
+		private bool KeyboardHookCallback(int keyCode, KeyModifier modifier, KeyState state)
+		{
+			var key = KeyInterop.KeyFromVirtualKey(keyCode);
+
+			TryExecute();
+
+			return false;
+		}
+
+		private bool MouseHookCallback(MouseButton button, MouseButtonState state, MouseInformation info)
+		{
+			var isTouch = info.IsTouch;
+
+			TryExecute();
+
+			return false;
+		}
+
 		private void ShowNotificationActive()
 		{
 			// TODO: Replace with actual icon!
+			// TODO: Extend INotification with IsEnabled or CanActivate, as the screen proctoring notification does not have any action or window!
 			IconResource = new XamlIconResource { Uri = new Uri("pack://application:,,,/SafeExamBrowser.UserInterface.Desktop;component/Images/ProctoringNotification_Active.xaml") };
 			Tooltip = text.Get(TextKey.Notification_ProctoringActiveTooltip);
 			NotificationChanged?.Invoke();
@@ -187,21 +238,41 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 
 		private void Timer_Elapsed(object sender, ElapsedEventArgs args)
 		{
-			try
+			TryExecute();
-			{
+		}
-				using (var screenShot = new ScreenShot(logger.CloneFor(nameof(ScreenShot)), settings))
-				{
-					screenShot.Take();
-					screenShot.Compress();
-					service.SendScreenShot(screenShot);
-				}
-			}
-			catch (Exception e)
-			{
-				logger.Error("Failed to process screen shot!", e);
-			}
 
-			timer.Start();
+		private void TryExecute()
+		{
+			if (MinimumIntervalElapsed() && Monitor.TryEnter(@lock))
+			{
+				last = DateTime.Now;
+				timer.Stop();
+
+				Task.Run(() =>
+				{
+					try
+					{
+						using (var screenShot = new ScreenShot(logger.CloneFor(nameof(ScreenShot)), settings))
+						{
+							screenShot.Take();
+							screenShot.Compress();
+							service.Send(screenShot);
+						}
+					}
+					catch (Exception e)
+					{
+						logger.Error("Failed to process screen shot!", e);
+					}
+				});
+
+				timer.Start();
+				Monitor.Exit(@lock);
+			}
+		}
+
+		private bool MinimumIntervalElapsed()
+		{
+			return DateTime.Now.Subtract(last) >= new TimeSpan(0, 0, 0, 0, settings.MinInterval);
 		}
 	}
 }

SafeExamBrowser.Proctoring/ScreenProctoring/Service/ServiceProxy.cs

@@ -69,7 +69,7 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring.Service
 			return new ServiceResponse(success, message);
 		}
 
-		internal ServiceResponse SendScreenShot(ScreenShot screenShot)
+		internal ServiceResponse Send(ScreenShot screenShot)
 		{
 			var request = new ScreenShotRequest(api, httpClient, logger, parser);
 			var success = request.TryExecute(screenShot, SessionId, out var message);