SEBWIN-302: Implemented configuration of internal PDF reader.

SafeExamBrowser.Browser/BrowserApplication.cs

@@ -156,10 +156,16 @@ namespace SafeExamBrowser.Browser
 
 			cefSettings.CefCommandLineArgs.Add("touch-events", "enabled");
 
+			if (!settings.AllowPdfReader)
+			{
+				cefSettings.CefCommandLineArgs.Add("disable-pdf-extension", "");
+			}
+
 			logger.Debug($"Cache path: {cefSettings.CachePath}");
 			logger.Debug($"Engine version: Chromium {Cef.ChromiumVersion}, CEF {Cef.CefVersion}, CefSharp {Cef.CefSharpVersion}");
 			logger.Debug($"Log file: {cefSettings.LogFile}");
 			logger.Debug($"Log severity: {cefSettings.LogSeverity}");
+			logger.Debug($"PDF reader: {(settings.AllowPdfReader ? "Enabled" : "Disabled")}");
 
 			return cefSettings;
 		}

SafeExamBrowser.Browser/Handlers/ResourceHandler.cs

@@ -9,6 +9,7 @@
 using System;
 using System.Collections.Specialized;
 using System.IO;
+using System.Net.Mime;
 using System.Reflection;
 using System.Security.Cryptography;
 using System.Text;
@@ -76,6 +77,22 @@ namespace SafeExamBrowser.Browser.Handlers
 			return base.OnBeforeResourceLoad(webBrowser, browser, frame, request, callback);
 		}
 
+		protected override bool OnResourceResponse(IWebBrowser chromiumWebBrowser, IBrowser browser, IFrame frame, IRequest request, IResponse response)
+		{
+			var abort = true;
+
+			if (RedirectToDisablePdfToolbar(request, response, out var url))
+			{
+				chromiumWebBrowser.Load(url);
+			}
+			else
+			{
+				abort = base.OnResourceResponse(chromiumWebBrowser, browser, frame, request, response);
+			}
+
+			return abort;
+		}
+
 		private void AppendCustomUserAgent(IRequest request)
 		{
 			var headers = new NameValueCollection(request.Headers);
@@ -100,20 +117,20 @@ namespace SafeExamBrowser.Browser.Handlers
 
 		private bool Block(IRequest request)
 		{
+			var block = false;
+
 			if (settings.Filter.ProcessContentRequests)
 			{
 				var result = filter.Process(new Request { Url = request.Url });
-				var block = result == FilterResult.Block;
 
-				if (block)
+				if (result == FilterResult.Block)
 				{
+					block = true;
 					logger.Info($"Blocked content request for '{request.Url}'.");
 				}
-
-				return block;
 			}
 
-			return false;
+			return block;
 		}
 
 		private bool IsMailtoUrl(string url)
@@ -121,6 +138,23 @@ namespace SafeExamBrowser.Browser.Handlers
 			return url.StartsWith(Uri.UriSchemeMailto);
 		}
 
+		private bool RedirectToDisablePdfToolbar(IRequest request, IResponse response, out string url)
+		{
+			const string DISABLE_PDF_TOOLBAR = "#toolbar=0";
+			var isPdf = response.Headers["Content-Type"] == MediaTypeNames.Application.Pdf;
+			var hasFragment = request.Url.Contains(DISABLE_PDF_TOOLBAR);
+			var redirect = settings.AllowPdfReader && !settings.AllowPdfReaderToolbar && isPdf && !hasFragment;
+
+			url = request.Url + DISABLE_PDF_TOOLBAR;
+
+			if (redirect)
+			{
+				logger.Info($"Redirecting to '{url}' to disable PDF reader toolbar.");
+			}
+
+			return redirect;
+		}
+
 		private void ReplaceSebScheme(IRequest request)
 		{
 			if (Uri.IsWellFormedUriString(request.Url, UriKind.RelativeOrAbsolute))

SafeExamBrowser.Configuration/ConfigurationData/DataMapping/BrowserDataMapper.cs

@@ -36,6 +36,9 @@ namespace SafeExamBrowser.Configuration.ConfigurationData.DataMapping
 				case Keys.Browser.AllowPageZoom:
 					MapAllowPageZoom(settings, value);
 					break;
+				case Keys.Browser.AllowPdfReaderToolbar:
+					MapAllowPdfReaderToolbar(settings, value);
+					break;
 				case Keys.Browser.AdditionalWindow.AllowAddressBar:
 					MapAllowAddressBarAdditionalWindow(settings, value);
 					break;
@@ -60,6 +63,9 @@ namespace SafeExamBrowser.Configuration.ConfigurationData.DataMapping
 				case Keys.Browser.DownloadDirectory:
 					MapDownloadDirectory(settings, value);
 					break;
+				case Keys.Browser.DownloadPdfFiles:
+					MapDownloadPdfFiles(settings, value);
+					break;
 				case Keys.Browser.EnableBrowser:
 					MapEnableBrowser(settings, value);
 					break;
@@ -197,6 +203,14 @@ namespace SafeExamBrowser.Configuration.ConfigurationData.DataMapping
 			}
 		}
 
+		private void MapAllowPdfReaderToolbar(AppSettings settings, object value)
+		{
+			if (value is bool allow)
+			{
+				settings.Browser.AllowPdfReaderToolbar = allow;
+			}
+		}
+
 		private void MapAllowReload(AppSettings settings, object value)
 		{
 			if (value is bool allow)
@@ -221,6 +235,14 @@ namespace SafeExamBrowser.Configuration.ConfigurationData.DataMapping
 			}
 		}
 
+		private void MapDownloadPdfFiles(AppSettings settings, object value)
+		{
+			if (value is bool download)
+			{
+				settings.Browser.AllowPdfReader = !download;
+			}
+		}
+
 		private void MapEnableBrowser(AppSettings settings, object value)
 		{
 			if (value is bool enable)

SafeExamBrowser.Configuration/ConfigurationData/DataValues.cs

@@ -126,6 +126,8 @@ namespace SafeExamBrowser.Configuration.ConfigurationData
 			settings.Browser.AllowCustomDownloadLocation = false;
 			settings.Browser.AllowDownloads = true;
 			settings.Browser.AllowPageZoom = true;
+			settings.Browser.AllowPdfReader = true;
+			settings.Browser.AllowPdfReaderToolbar = false;
 			settings.Browser.AllowUploads = true;
 			settings.Browser.MainWindow.AllowAddressBar = false;
 			settings.Browser.MainWindow.AllowBackwardNavigation = false;

SafeExamBrowser.Configuration/ConfigurationData/Keys.cs

@@ -46,9 +46,11 @@ namespace SafeExamBrowser.Configuration.ConfigurationData
 			internal const string AllowDeveloperConsole = "allowDeveloperConsole";
 			internal const string AllowDownloadsAndUploads = "allowDownUploads";
 			internal const string AllowPageZoom = "enableZoomPage";
+			internal const string AllowPdfReaderToolbar = "allowPDFReaderToolbar";
 			internal const string CustomUserAgentDesktop = "browserUserAgentWinDesktopModeCustom";
 			internal const string CustomUserAgentMobile = "browserUserAgentWinTouchModeCustom";
 			internal const string DownloadDirectory = "downloadDirectoryWin";
+			internal const string DownloadPdfFiles = "downloadPDFFiles";
 			internal const string EnableBrowser = "enableSebBrowser";
 			internal const string PopupPolicy = "newBrowserWindowByLinkPolicy";
 			internal const string PopupBlockForeignHost = "newBrowserWindowByLinkBlockForeign";

SafeExamBrowser.Settings/Browser/BrowserSettings.cs

@@ -41,6 +41,16 @@ namespace SafeExamBrowser.Settings.Browser
 		/// </summary>
 		public bool AllowPageZoom { get; set; }
 
+		/// <summary>
+		/// Determines whether the internal PDF reader of the browser application is enabled. If not, documents will be downloaded by default.
+		/// </summary>
+		public bool AllowPdfReader { get; set; }
+
+		/// <summary>
+		/// Determines whether the toolbar of the internal PDF reader (which allows to e.g. download or print a document) will be enabled.
+		/// </summary>
+		public bool AllowPdfReaderToolbar { get; set; }
+
 		/// <summary>
 		/// Determines whether the user will be allowed to upload files.
 		/// </summary>