seb-win-refactoring/SafeExamBrowser.Monitoring/Keyboard/KeyboardInterceptor.cs
2018-02-15 15:42:54 +01:00

74 lines
2.3 KiB
C#

/*
* Copyright (c) 2018 ETH Zürich, Educational Development and Technology (LET)
*
* 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.Linq;
using System.Windows.Input;
using SafeExamBrowser.Contracts.Configuration.Settings;
using SafeExamBrowser.Contracts.Logging;
using SafeExamBrowser.Contracts.Monitoring;
namespace SafeExamBrowser.Monitoring.Keyboard
{
public class KeyboardInterceptor : IKeyboardInterceptor
{
private KeyboardSettings settings;
private ILogger logger;
public KeyboardInterceptor(KeyboardSettings settings, ILogger logger)
{
this.logger = logger;
this.settings = settings;
}
public bool Block(int keyCode, KeyModifier modifier, KeyState state)
{
var block = false;
var key = KeyInterop.KeyFromVirtualKey(keyCode);
block |= key == Key.Apps;
block |= key == Key.F1;
block |= key == Key.F2;
block |= key == Key.F3;
block |= key == Key.F4;
block |= key == Key.F6;
block |= key == Key.F7;
block |= key == Key.F8;
block |= key == Key.F9;
block |= key == Key.F10;
block |= key == Key.F11;
block |= key == Key.F12;
block |= key == Key.LWin;
block |= key == Key.PrintScreen;
block |= key == Key.RWin;
block |= key == Key.Escape && modifier.HasFlag(KeyModifier.Alt);
block |= key == Key.Escape && modifier.HasFlag(KeyModifier.Ctrl);
block |= key == Key.Space && modifier.HasFlag(KeyModifier.Alt);
block |= !settings.AllowAltTab && key == Key.Tab && modifier.HasFlag(KeyModifier.Alt);
block |= !settings.AllowEsc && key == Key.Escape && modifier == KeyModifier.None;
block |= !settings.AllowF5 && key == Key.F5;
if (block)
{
Log(key, keyCode, modifier, state);
}
return block;
}
private void Log(Key key, int keyCode, KeyModifier modifier, KeyState state)
{
var modifierFlags = Enum.GetValues(typeof(KeyModifier)).OfType<KeyModifier>().Where(m => m != KeyModifier.None && modifier.HasFlag(m));
var modifiers = modifierFlags.Any() ? String.Join(" + ", modifierFlags) + " + " : string.Empty;
logger.Info($"Blocked '{modifiers}{key}' ({key} = {keyCode}) when {state.ToString().ToLower()}.");
}
}
}