SEBWIN-221: Changed configuration file handling to support special case with resource URL as startup URL and switched to data stream instead of byte array.

SafeExamBrowser.Configuration/ConfigurationRepository.cs

@@ -11,7 +11,6 @@ using System.Collections.Generic;
 using System.IO;
 using System.IO.Compression;
 using System.Linq;
-using SafeExamBrowser.Configuration.DataFormats;
 using SafeExamBrowser.Contracts.Configuration;
 using SafeExamBrowser.Contracts.Configuration.Settings;
 using SafeExamBrowser.Contracts.Logging;
@@ -132,29 +131,17 @@ namespace SafeExamBrowser.Configuration
 
 			try
 			{
-				var resourceLoader = resourceLoaders.FirstOrDefault(l => l.CanLoad(resource));
+				var status = TryLoadData(resource, out Stream data);
 
-				if (resourceLoader != null)
+				switch (status)
 				{
-					var data = resourceLoader.Load(resource);
+					case LoadStatus.LoadWithBrowser:
-					var dataFormat = dataFormats.FirstOrDefault(f => f.CanParse(data));
+						return HandleBrowserResource(resource, out settings);
-
+					case LoadStatus.Success:
-					logger.Info($"Successfully loaded {data.Length / 1000.0} KB data from '{resource}' using {resourceLoader.GetType().Name}.");
+						return TryParseData(data, out settings, adminPassword, settingsPassword);
-
-					if (dataFormat is HtmlFormat)
-					{
-						return HandleHtml(resource, out settings);
-					}
-
-					if (dataFormat != null)
-					{
-						return dataFormat.TryParse(data, out settings, adminPassword, settingsPassword);
-					}
 				}
 
-				logger.Warn($"No {(resourceLoader == null ? "resource loader" : "data format")} found for '{resource}'!");
+				return status;
-
-				return LoadStatus.NotSupported;
 			}
 			catch (Exception e)
 			{
@@ -164,13 +151,53 @@ namespace SafeExamBrowser.Configuration
 			}
 		}
 
-		private LoadStatus HandleHtml(Uri resource, out Settings settings)
+		private LoadStatus TryLoadData(Uri resource, out Stream data)
 		{
-			logger.Info($"Loaded data appears to be HTML, loading default settings and using '{resource}' as startup URL.");
+			var status = LoadStatus.NotSupported;
+			var resourceLoader = resourceLoaders.FirstOrDefault(l => l.CanLoad(resource));
 
+			data = default(Stream);
+
+			if (resourceLoader != null)
+			{
+				status = resourceLoader.TryLoad(resource, out data);
+				logger.Info($"Tried to load data from '{resource}' using {resourceLoader.GetType().Name} -> Result: {status}.");
+			}
+			else
+			{
+				logger.Warn($"No resource loader found for '{resource}'!");
+			}
+
+			return status;
+		}
+
+		private LoadStatus TryParseData(Stream data, out Settings settings, string adminPassword, string settingsPassword)
+		{
+			var status = LoadStatus.NotSupported;
+			var dataFormat = dataFormats.FirstOrDefault(f => f.CanParse(data));
+
+			settings = default(Settings);
+
+			if (dataFormat != null)
+			{
+				status = dataFormat.TryParse(data, out settings, adminPassword, settingsPassword);
+				logger.Info($"Tried to parse data from '{data}' using {dataFormat.GetType().Name} -> Result: {status}.");
+			}
+			else
+			{
+				logger.Warn($"No data format found for '{data}'!");
+			}
+
+			return status;
+		}
+
+		private LoadStatus HandleBrowserResource(Uri resource, out Settings settings)
+		{
 			settings = LoadDefaultSettings();
 			settings.Browser.StartUrl = resource.AbsoluteUri;
 
+			logger.Info($"The resource needs authentication or is HTML data, loaded default settings with '{resource}' as startup URL.");
+
 			return LoadStatus.Success;
 		}
 

SafeExamBrowser.Configuration/DataFormats/DefaultFormat.cs

@@ -6,6 +6,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+using System.IO;
 using SafeExamBrowser.Contracts.Configuration;
 using SafeExamBrowser.Contracts.Configuration.Settings;
 using SafeExamBrowser.Contracts.Logging;
@@ -21,17 +22,14 @@ namespace SafeExamBrowser.Configuration.DataFormats
 			this.logger = logger;
 		}
 
-		public bool CanParse(byte[] data)
+		public bool CanParse(Stream data)
 		{
-			return true;
+			return false;
 		}
 
-		public LoadStatus TryParse(byte[] data, out Settings settings, string adminPassword = null, string settingsPassword = null)
+		public LoadStatus TryParse(Stream data, out Settings settings, string adminPassword = null, string settingsPassword = null)
 		{
-			settings = new Settings();
+			throw new System.NotImplementedException();
-			settings.ServicePolicy = ServicePolicy.Optional;
-
-			return LoadStatus.Success;
 		}
 	}
 }

SafeExamBrowser.Configuration/DataFormats/HtmlFormat.cs

@@ -1,34 +0,0 @@
-/*
- * 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 SafeExamBrowser.Contracts.Configuration;
-using SafeExamBrowser.Contracts.Configuration.Settings;
-using SafeExamBrowser.Contracts.Logging;
-
-namespace SafeExamBrowser.Configuration.DataFormats
-{
-	public class HtmlFormat : IDataFormat
-	{
-		private ILogger logger;
-
-		public HtmlFormat(ILogger logger)
-		{
-			this.logger = logger;
-		}
-
-		public bool CanParse(byte[] data)
-		{
-			return false;
-		}
-
-		public LoadStatus TryParse(byte[] data, out Settings settings, string adminPassword = null, string settingsPassword = null)
-		{
-			throw new System.NotImplementedException();
-		}
-	}
-}

SafeExamBrowser.Configuration/DataFormats/XmlFormat.cs

@@ -6,6 +6,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+using System.IO;
 using SafeExamBrowser.Contracts.Configuration;
 using SafeExamBrowser.Contracts.Configuration.Settings;
 using SafeExamBrowser.Contracts.Logging;
@@ -21,12 +22,12 @@ namespace SafeExamBrowser.Configuration.DataFormats
 			this.logger = logger;
 		}
 
-		public bool CanParse(byte[] data)
+		public bool CanParse(Stream data)
 		{
 			return false;
 		}
 
-		public LoadStatus TryParse(byte[] data, out Settings settings, string adminPassword = null, string settingsPassword = null)
+		public LoadStatus TryParse(Stream data, out Settings settings, string adminPassword = null, string settingsPassword = null)
 		{
 			throw new System.NotImplementedException();
 		}

SafeExamBrowser.Configuration/ResourceLoaders/FileResourceLoader.cs

@@ -24,23 +24,27 @@ namespace SafeExamBrowser.Configuration.ResourceLoaders
 
 		public bool CanLoad(Uri resource)
 		{
-			if (resource.IsFile && File.Exists(resource.AbsolutePath))
+			var exists = resource.IsFile && File.Exists(resource.AbsolutePath);
+
+			if (exists)
 			{
 				logger.Debug($"Can load '{resource}' as it references an existing file.");
-
+			}
-				return true;
+			else
+			{
+				logger.Debug($"Can't load '{resource}' since it isn't a file URI or no file exists at the specified path.");
 			}
 
-			logger.Debug($"Can't load '{resource}' since it isn't a file URI or no file exists at the specified path.");
+			return exists;
-
-			return false;
 		}
 
-		public byte[] Load(Uri resource)
+		public LoadStatus TryLoad(Uri resource, out Stream data)
 		{
 			logger.Debug($"Loading data from '{resource}'...");
+			data = new FileStream(resource.AbsolutePath, FileMode.Open, FileAccess.Read);
+			logger.Debug($"Created {data} for {data.Length / 1000.0} KB data in '{resource}'.");
 
-			return File.ReadAllBytes(resource.AbsolutePath);
+			return LoadStatus.Success;
 		}
 	}
 }

SafeExamBrowser.Configuration/ResourceLoaders/NetworkResourceLoader.cs

@@ -7,8 +7,11 @@
  */
 
 using System;
+using System.IO;
 using System.Linq;
+using System.Net;
 using System.Net.Http;
+using System.Net.Mime;
 using System.Threading.Tasks;
 using SafeExamBrowser.Contracts.Configuration;
 using SafeExamBrowser.Contracts.Logging;
@@ -20,6 +23,12 @@ namespace SafeExamBrowser.Configuration.ResourceLoaders
 		private AppConfig appConfig;
 		private ILogger logger;
 
+		private string[] SupportedContentTypes => new[]
+		{
+			MediaTypeNames.Application.Octet,
+			MediaTypeNames.Text.Xml
+		};
+
 		private string[] SupportedSchemes => new[]
 		{
 			appConfig.SebUriScheme,
@@ -36,54 +45,41 @@ namespace SafeExamBrowser.Configuration.ResourceLoaders
 
 		public bool CanLoad(Uri resource)
 		{
-			if (SupportedSchemes.Contains(resource.Scheme) && IsAvailable(resource))
+			var available = SupportedSchemes.Contains(resource.Scheme) && IsAvailable(resource);
+
+			if (available)
 			{
 				logger.Debug($"Can load '{resource}' as it references an existing network resource.");
-
+			}
-				return true;
+			else
+			{
+				logger.Debug($"Can't load '{resource}' since its URI scheme is not supported or the resource is unavailable.");
 			}
 
-			logger.Debug($"Can't load '{resource}' since its URI scheme is not supported or the resource is unavailable.");
+			return available;
-
-			return false;
 		}
 
-		public byte[] Load(Uri resource)
+		public LoadStatus TryLoad(Uri resource, out Stream data)
 		{
 			var uri = BuildUriFor(resource);
 
-			logger.Debug($"Downloading data from '{uri}'...");
+			logger.Debug($"Sending GET request for '{uri}'...");
 
 			var request = new HttpRequestMessage(HttpMethod.Get, uri);
 			var response = Execute(request);
 
-			logger.Debug($"Sent GET request for '{uri}', received response '{(int) response.StatusCode} - {response.ReasonPhrase}'.");
+			logger.Debug($"Received response '{ToString(response)}'.");
 
-			var data = Extract(response.Content);
+			if (IsUnauthorized(response) || HasHtmlContent(response))
-
-			logger.Debug($"Extracted {data.Length / 1000.0} KB data from response.");
-
-			return data;
-		}
-
-		private bool IsAvailable(Uri resource)
-		{
-			try
 			{
-				var uri = BuildUriFor(resource);
+				return HandleBrowserResource(response, out data);
-				var request = new HttpRequestMessage(HttpMethod.Head, uri);
-				var response = Execute(request);
-
-				logger.Debug($"Sent HEAD request for '{uri}', received response '{(int) response.StatusCode} - {response.ReasonPhrase}'.");
-
-				return response.IsSuccessStatusCode;
 			}
-			catch (Exception e)
-			{
-				logger.Error($"Failed to check availability of '{resource}'!", e);
 
-				return false;
+			logger.Debug($"Trying to extract response data...");
-			}
+			data = Extract(response.Content);
+			logger.Debug($"Created {data} for {data.Length / 1000.0} KB data of response body.");
+
+			return LoadStatus.Success;
 		}
 
 		private Uri BuildUriFor(Uri resource)
@@ -94,6 +90,29 @@ namespace SafeExamBrowser.Configuration.ResourceLoaders
 			return builder.Uri;
 		}
 
+		private HttpResponseMessage Execute(HttpRequestMessage request)
+		{
+			var task = Task.Run(async () =>
+			{
+				using (var client = new HttpClient())
+				{
+					return await client.SendAsync(request);
+				}
+			});
+
+			return task.GetAwaiter().GetResult();
+		}
+
+		private Stream Extract(HttpContent content)
+		{
+			var task = Task.Run(async () =>
+			{
+				return await content.ReadAsStreamAsync();
+			});
+
+			return task.GetAwaiter().GetResult();
+		}
+
 		private string GetSchemeFor(Uri resource)
 		{
 			if (resource.Scheme == appConfig.SebUriScheme)
@@ -109,27 +128,52 @@ namespace SafeExamBrowser.Configuration.ResourceLoaders
 			return resource.Scheme;
 		}
 
-		private HttpResponseMessage Execute(HttpRequestMessage request)
+		private LoadStatus HandleBrowserResource(HttpResponseMessage response, out Stream data)
 		{
-			var task = Task.Run(async () =>
+			data = default(Stream);
-			{
-				using (var client = new HttpClient())
-				{
-					return await client.SendAsync(request);
-				}
-			});
 
-			return task.GetAwaiter().GetResult();
+			logger.Debug($"The {(IsUnauthorized(response) ? "resource needs authentication" : " response data is HTML")}.");
+
+			return LoadStatus.LoadWithBrowser;
 		}
 
-		private byte[] Extract(HttpContent content)
+		private bool HasHtmlContent(HttpResponseMessage response)
 		{
-			var task = Task.Run(async () =>
+			return response.Content.Headers.ContentType.MediaType == MediaTypeNames.Text.Html;
-			{
+		}
-				return await content.ReadAsByteArrayAsync();
-			});
 
-			return task.GetAwaiter().GetResult();
+		private bool IsAvailable(Uri resource)
+		{
+			try
+			{
+				var uri = BuildUriFor(resource);
+
+				logger.Debug($"Sending HEAD request for '{uri}'...");
+
+				var request = new HttpRequestMessage(HttpMethod.Head, uri);
+				var response = Execute(request);
+				var isAvailable = response.IsSuccessStatusCode || IsUnauthorized(response);
+
+				logger.Debug($"Received response '{ToString(response)}'.");
+
+				return isAvailable;
+			}
+			catch (Exception e)
+			{
+				logger.Error($"Failed to check availability of '{resource}'!", e);
+
+				return false;
+			}
+		}
+
+		private bool IsUnauthorized(HttpResponseMessage response)
+		{
+			return response.StatusCode == HttpStatusCode.Unauthorized;
+		}
+
+		private string ToString(HttpResponseMessage response)
+		{
+			return $"{(int)response.StatusCode} - {response.ReasonPhrase}";
 		}
 	}
 }

SafeExamBrowser.Configuration/SafeExamBrowser.Configuration.csproj

@@ -54,7 +54,6 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="DataFormats\DefaultFormat.cs" />
-    <Compile Include="DataFormats\HtmlFormat.cs" />
     <Compile Include="DataFormats\XmlFormat.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="ConfigurationRepository.cs" />

SafeExamBrowser.Contracts/Configuration/IConfigurationRepository.cs

@@ -31,12 +31,12 @@ namespace SafeExamBrowser.Contracts.Configuration
 		Settings.Settings LoadDefaultSettings();
 
 		/// <summary>
-		/// Registers the specified <see cref="IDataFormat"/> as option to parse configuration data.
+		/// Registers the specified <see cref="IDataFormat"/> as option to parse data from a configuration resource.
 		/// </summary>
 		void Register(IDataFormat dataFormat);
 
 		/// <summary>
-		/// Registers the specified <see cref="IResourceLoader"/> as option to load configuration data.
+		/// Registers the specified <see cref="IResourceLoader"/> as option to load data from a configuration resource.
 		/// </summary>
 		void Register(IResourceLoader resourceLoader);
 

SafeExamBrowser.Contracts/Configuration/IDataFormat.cs

@@ -6,21 +6,24 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+using System.IO;
+
 namespace SafeExamBrowser.Contracts.Configuration
 {
 	/// <summary>
-	/// Defines the data format for a configuration file.
+	/// Provides functionality to parse configuration data with a particular format.
 	/// </summary>
 	public interface IDataFormat
 	{
 		/// <summary>
 		/// Indicates whether the given data complies with the required format.
 		/// </summary>
-		bool CanParse(byte[] data);
+		bool CanParse(Stream data);
 
 		/// <summary>
-		/// Attempts to parse the given binary data.
+		/// Tries to parse the given data, using the optional passwords. As long as the result is not <see cref="LoadStatus.Success"/>,
+		/// the referenced settings may be <c>null</c> or in an undefinable state!
 		/// </summary>
-		LoadStatus TryParse(byte[] data, out Settings.Settings settings, string adminPassword = null, string settingsPassword = null);
+		LoadStatus TryParse(Stream data, out Settings.Settings settings, string adminPassword = null, string settingsPassword = null);
 	}
 }

SafeExamBrowser.Contracts/Configuration/IResourceLoader.cs

@@ -7,11 +7,12 @@
  */
 
 using System;
+using System.IO;
 
 namespace SafeExamBrowser.Contracts.Configuration
 {
 	/// <summary>
-	/// Loads binary data from a particular resource.
+	/// Provides functionality to load configuration data from a particular resource.
 	/// </summary>
 	public interface IResourceLoader
 	{
@@ -21,8 +22,8 @@ namespace SafeExamBrowser.Contracts.Configuration
 		bool CanLoad(Uri resource);
 
 		/// <summary>
-		/// Loads the binary data from the specified resource.
+		/// Tries to load the configuration data from the specified resource.
 		/// </summary>
-		byte[] Load(Uri resource);
+		LoadStatus TryLoad(Uri resource, out Stream data);
 	}
 }

SafeExamBrowser.Contracts/Configuration/LoadStatus.cs

@@ -9,7 +9,7 @@
 namespace SafeExamBrowser.Contracts.Configuration
 {
 	/// <summary>
-	/// Defines all possible results of an attempt to load a configuration file.
+	/// Defines all possible results of an attempt to load a configuration resource.
 	/// </summary>
 	public enum LoadStatus
 	{
@@ -19,10 +19,15 @@ namespace SafeExamBrowser.Contracts.Configuration
 		AdminPasswordNeeded = 1,
 
 		/// <summary>
-		/// Indicates that a resource does not comply with the required data format.
+		/// Indicates that a resource does not comply with the declared data format.
 		/// </summary>
 		InvalidData,
 
+		/// <summary>
+		/// Indicates that a resource needs to be loaded with the browser.
+		/// </summary>
+		LoadWithBrowser,
+
 		/// <summary>
 		/// Indicates that a resource is not supported.
 		/// </summary>

SafeExamBrowser.Runtime/CompositionRoot.cs

@@ -118,7 +118,6 @@ namespace SafeExamBrowser.Runtime
 			appConfig = configuration.InitializeAppConfig();
 
 			configuration.Register(new DefaultFormat(new ModuleLogger(logger, nameof(DefaultFormat))));
-			configuration.Register(new HtmlFormat(new ModuleLogger(logger, nameof(HtmlFormat))));
 			configuration.Register(new XmlFormat(new ModuleLogger(logger, nameof(XmlFormat))));
 			configuration.Register(new FileResourceLoader(new ModuleLogger(logger, nameof(FileResourceLoader))));
 			configuration.Register(new NetworkResourceLoader(appConfig, new ModuleLogger(logger, nameof(NetworkResourceLoader))));

SafeExamBrowser.Runtime/Operations/ConfigurationOperation.cs

@@ -48,17 +48,15 @@ namespace SafeExamBrowser.Runtime.Operations
 
 			if (isValidUri)
 			{
-				logger.Info($"Attempting to load settings from '{uri}'...");
-
 				var result = LoadSettings(uri);
 
-				HandleClientConfiguration(ref result);
+				HandleClientConfiguration(ref result, uri);
 				LogOperationResult(result);
 
 				return result;
 			}
 
-			logger.Info("No valid settings resource specified nor found in PROGRAMDATA or APPDATA - loading default settings...");
+			logger.Info("No valid configuration resource specified nor found in PROGRAMDATA or APPDATA - loading default settings...");
 			Context.Next.Settings = configuration.LoadDefaultSettings();
 
 			return OperationResult.Success;
@@ -73,8 +71,6 @@ namespace SafeExamBrowser.Runtime.Operations
 
 			if (isValidUri)
 			{
-				logger.Info($"Attempting to load settings from '{uri}'...");
-
 				var result = LoadSettings(uri);
 
 				LogOperationResult(result);
@@ -82,7 +78,7 @@ namespace SafeExamBrowser.Runtime.Operations
 				return result;
 			}
 
-			logger.Warn($"The resource specified for reconfiguration does not exist or is not a file!");
+			logger.Warn($"The resource specified for reconfiguration does not exist or is not valid!");
 
 			return OperationResult.Failed;
 		}
@@ -126,10 +122,17 @@ namespace SafeExamBrowser.Runtime.Operations
 			if (status == LoadStatus.Success)
 			{
 				Context.Next.Settings = settings;
-
+			}
-				return OperationResult.Success;
+			else
+			{
+				ShowFailureMessage(status, uri);
 			}
 
+			return status == LoadStatus.Success ? OperationResult.Success : OperationResult.Failed;
+		}
+
+		private void ShowFailureMessage(LoadStatus status, Uri uri)
+		{
 			switch (status)
 			{
 				case LoadStatus.InvalidData:
@@ -142,8 +145,6 @@ namespace SafeExamBrowser.Runtime.Operations
 					ActionRequired?.Invoke(new UnexpectedErrorMessageArgs(uri.ToString()));
 					break;
 			}
-
-			return OperationResult.Failed;
 		}
 
 		private PasswordRequiredEventArgs TryGetPassword(LoadStatus status)
@@ -169,21 +170,21 @@ namespace SafeExamBrowser.Runtime.Operations
 			{
 				path = commandLineArgs[1];
 				isValidUri = Uri.TryCreate(path, UriKind.Absolute, out uri);
-				logger.Info($"Found command-line argument for settings file: '{path}', the URI is {(isValidUri ? "valid" : "invalid")}.");
+				logger.Info($"Found command-line argument for configuration resource: '{path}', the URI is {(isValidUri ? "valid" : "invalid")}.");
 			}
 
 			if (!isValidUri && File.Exists(programDataSettings))
 			{
 				path = programDataSettings;
 				isValidUri = Uri.TryCreate(path, UriKind.Absolute, out uri);
-				logger.Info($"Found settings file in PROGRAMDATA: '{path}', the URI is {(isValidUri ? "valid" : "invalid")}.");
+				logger.Info($"Found configuration file in PROGRAMDATA: '{path}', the URI is {(isValidUri ? "valid" : "invalid")}.");
 			}
 
 			if (!isValidUri && File.Exists(appDataSettings))
 			{
 				path = appDataSettings;
 				isValidUri = Uri.TryCreate(path, UriKind.Absolute, out uri);
-				logger.Info($"Found settings file in APPDATA: '{path}', the URI is {(isValidUri ? "valid" : "invalid")}.");
+				logger.Info($"Found configuration file in APPDATA: '{path}', the URI is {(isValidUri ? "valid" : "invalid")}.");
 			}
 
 			return isValidUri;
@@ -199,9 +200,13 @@ namespace SafeExamBrowser.Runtime.Operations
 			return isValidUri;
 		}
 
-		private void HandleClientConfiguration(ref OperationResult result)
+		private void HandleClientConfiguration(ref OperationResult result, Uri uri)
 		{
-			if (result == OperationResult.Success && Context.Next.Settings.ConfigurationMode == ConfigurationMode.ConfigureClient)
+			var configureMode = Context.Next.Settings?.ConfigurationMode == ConfigurationMode.ConfigureClient;
+			var loadWithBrowser = Context.Next.Settings?.Browser.StartUrl == uri.AbsoluteUri;
+			var successful = result == OperationResult.Success;
+
+			if (successful && configureMode && !loadWithBrowser)
 			{
 				var args = new ConfigurationCompletedEventArgs();