SEBWIN-220: Moved exception handling to proxy implementations by introducing the CommunicationResult.

SafeExamBrowser.Client/Behaviour/ClientController.cs

@@ -101,23 +101,22 @@ namespace SafeExamBrowser.Client.Behaviour
 			{
 				RegisterEvents();
 
-				try
+				var communication = runtime.InformClientReady();
-				{
-					runtime.InformClientReady();
-				}
-				catch (Exception e)
-				{
-					logger.Error("Failed to inform runtime that client is ready!", e);
-
-					return false;
-				}
 
+				if (communication.Success)
+				{
 					splashScreen.Hide();
 
 					logger.Info("--- Application successfully initialized ---");
 					logger.Log(string.Empty);
 				}
 				else
+				{
+					success = false;
+					logger.Error("Failed to inform runtime that client is ready!");
+				}
+			}
+			else
 			{
 				logger.Info("--- Application startup aborted! ---");
 				logger.Log(string.Empty);
@@ -227,14 +226,15 @@ namespace SafeExamBrowser.Client.Behaviour
 		{
 			if (success)
 			{
-				try
+				var communication = runtime.RequestReconfiguration(filePath);
+
+				if (communication.Success)
 				{
-					runtime.RequestReconfiguration(filePath);
 					logger.Info($"Sent reconfiguration request for '{filePath}' to the runtime.");
 				}
-				catch (Exception e)
+				else
 				{
-					logger.Error($"Failed to communicate reconfiguration request for '{filePath}'!", e);
+					logger.Error($"Failed to communicate reconfiguration request for '{filePath}'!");
 					messageBox.Show(TextKey.MessageBox_ReconfigurationError, TextKey.MessageBox_ReconfigurationErrorTitle, icon: MessageBoxIcon.Error);
 				}
 			}
@@ -287,13 +287,11 @@ namespace SafeExamBrowser.Client.Behaviour
 
 			if (result == MessageBoxResult.Yes)
 			{
-				try
+				var communication = runtime.RequestShutdown();
+
+				if (!communication.Success)
 				{
-					runtime.RequestShutdown();
+					logger.Error("Failed to communicate shutdown request to the runtime!");
-				}
-				catch (Exception e)
-				{
-					logger.Error("Failed to communicate shutdown request to the runtime!", e);
 					messageBox.Show(TextKey.MessageBox_QuitError, TextKey.MessageBox_QuitErrorTitle, icon: MessageBoxIcon.Error);
 				}
 			}

SafeExamBrowser.Client/Behaviour/Operations/ConfigurationOperation.cs

@@ -38,7 +38,8 @@ namespace SafeExamBrowser.Client.Behaviour.Operations
 
 			try
 			{
-				var config = runtime.GetConfiguration();
+				var communication = runtime.GetConfiguration();
+				var config = communication.Value.Configuration;
 
 				configuration.AppConfig = config.AppConfig;
 				configuration.SessionId = config.SessionId;

SafeExamBrowser.Client/Behaviour/Operations/RuntimeConnectionOperation.cs

@@ -36,25 +36,18 @@ namespace SafeExamBrowser.Client.Behaviour.Operations
 			logger.Info("Initializing runtime connection...");
 			ProgressIndicator?.UpdateText(TextKey.ProgressIndicator_InitializeRuntimeConnection);
 
-			try
-			{
 			connected = runtime.Connect(token);
-			}
-			catch (Exception e)
-			{
-				logger.Error("An unexpected error occurred while trying to connect to the runtime!", e);
-			}
 
-			if (!connected)
+			if (connected)
+			{
+				logger.Info("Successfully connected to the runtime.");
+			}
+			else
 			{
 				logger.Error("Failed to connect to the runtime. Aborting startup...");
-
-				return OperationResult.Failed;
 			}
 
-			logger.Info("Successfully connected to the runtime.");
+			return connected ? OperationResult.Success : OperationResult.Failed;
-
-			return OperationResult.Success;
 		}
 
 		public OperationResult Repeat()
@@ -69,13 +62,15 @@ namespace SafeExamBrowser.Client.Behaviour.Operations
 
 			if (connected)
 			{
-				try
+				var success = runtime.Disconnect();
+
+				if (success)
 				{
-					runtime.Disconnect();
+					logger.Info("Successfully disconnected from the runtime.");
 				}
-				catch (Exception e)
+				else
 				{
-					logger.Error("Failed to disconnect from runtime host!", e);
+					logger.Error("Failed to disconnect from the runtime!");
 				}
 			}
 		}

SafeExamBrowser.Client/CompositionRoot.cs

@@ -89,6 +89,7 @@ namespace SafeExamBrowser.Client
 			operations.Enqueue(new I18nOperation(logger, text));
 			operations.Enqueue(new RuntimeConnectionOperation(logger, runtimeProxy, startupToken));
 			operations.Enqueue(new ConfigurationOperation(configuration, logger, runtimeProxy));
+			operations.Enqueue(new DelegateOperation(UpdateAppConfig));
 			operations.Enqueue(new DelayedInitializationOperation(BuildCommunicationHostOperation));
 			// TODO
 			//operations.Enqueue(new DelayedInitializationOperation(BuildKeyboardInterceptorOperation));
@@ -202,9 +203,13 @@ namespace SafeExamBrowser.Client
 			return operation;
 		}
 
-		private void UpdateClientControllerDependencies()
+		private void UpdateAppConfig()
 		{
 			ClientController.AppConfig = configuration.AppConfig;
+		}
+
+		private void UpdateClientControllerDependencies()
+		{
 			ClientController.Browser = browserController;
 			ClientController.ClientHost = clientHost;
 			ClientController.SessionId = configuration.SessionId;

SafeExamBrowser.Contracts/Communication/ICommunicationProxy.cs

@@ -23,17 +23,14 @@ namespace SafeExamBrowser.Contracts.Communication
 		event CommunicationEventHandler ConnectionLost;
 
 		/// <summary>
-		/// Tries to establish a connection. Returns <c>true</c> if the connection has been accepted, otherwise <c>false</c>. If a
+		/// Tries to establish a connection. Returns <c>true</c> if the connection has been successful, otherwise <c>false</c>. If a
 		/// connection was successfully established and the auto-ping flag is set, the connection status will be periodically checked.
 		/// </summary>
-		/// <exception cref="System.ServiceModel.*">If the communication failed.</exception>
 		bool Connect(Guid? token = null, bool autoPing = true);
 
 		/// <summary>
-		/// Terminates an open connection. Returns <c>true</c> if the disconnection has been acknowledged, otherwise <c>false</c>.
+		/// Terminates an open connection. Returns <c>true</c> if the disconnection has been successful, otherwise <c>false</c>.
 		/// </summary>
-		/// <exception cref="InvalidOperationException">If no connection has been established.</exception>
-		/// <exception cref="System.ServiceModel.*">If the communication failed.</exception>
 		bool Disconnect();
 	}
 }

SafeExamBrowser.Contracts/Communication/Proxies/CommunicationResult.cs

@@ -0,0 +1,43 @@
+/*
+ * 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/.
+ */
+
+namespace SafeExamBrowser.Contracts.Communication.Proxies
+{
+	/// <summary>
+	/// Defines the result of a communication between an <see cref="ICommunicationProxy"/> and its <see cref="ICommunicationHost"/>.
+	/// </summary>
+	public class CommunicationResult
+	{
+		/// <summary>
+		/// Defines whether the communication was successful or not.
+		/// </summary>
+		public bool Success { get; protected set; }
+
+		public CommunicationResult(bool success)
+		{
+			Success = success;
+		}
+	}
+
+	/// <summary>
+	/// Defines the result of a communication between an <see cref="ICommunicationProxy"/> and its <see cref="ICommunicationHost"/>.
+	/// </summary>
+	/// <typeparam name="T">The type of the expected response value.</typeparam>
+	public class CommunicationResult<T> : CommunicationResult
+	{
+		/// <summary>
+		/// The response value. Can be <c>null</c> or <c>default(T)</c> in case the communication has failed!
+		/// </summary>
+		public T Value { get; protected set; }
+
+		public CommunicationResult(bool success, T value) : base(success)
+		{
+			Value = value;
+		}
+	}
+}

SafeExamBrowser.Contracts/Communication/Proxies/IClientProxy.cs

@@ -19,24 +19,21 @@ namespace SafeExamBrowser.Contracts.Communication.Proxies
 		/// <summary>
 		/// Informs the client that the reconfiguration request for the specified file was denied.
 		/// </summary>
-		void InformReconfigurationDenied(string filePath);
+		CommunicationResult InformReconfigurationDenied(string filePath);
 
 		/// <summary>
 		/// Instructs the client to initiate its shutdown procedure.
 		/// </summary>
-		/// <exception cref="System.ServiceModel.*">If the communication failed.</exception>
+		CommunicationResult InitiateShutdown();
-		void InitiateShutdown();
 
 		/// <summary>
 		/// Instructs the client to submit its authentication data.
 		/// </summary>
-		/// <exception cref="System.ServiceModel.*">If the communication failed.</exception>
+		CommunicationResult<AuthenticationResponse> RequestAuthentication();
-		AuthenticationResponse RequestAuthentication();
 
 		/// <summary>
 		/// Requests the client to render a password dialog and subsequently return the interaction result as separate message.
 		/// </summary>
-		/// <exception cref="System.ServiceModel.*">If the communication failed.</exception>
+		CommunicationResult RequestPassword(PasswordRequestPurpose purpose, Guid requestId);
-		void RequestPassword(PasswordRequestPurpose purpose, Guid requestId);
 	}
 }

SafeExamBrowser.Contracts/Communication/Proxies/IRuntimeProxy.cs

@@ -7,7 +7,7 @@
  */
 
 using System;
-using SafeExamBrowser.Contracts.Configuration;
+using SafeExamBrowser.Contracts.Communication.Data;
 
 namespace SafeExamBrowser.Contracts.Communication.Proxies
 {
@@ -19,32 +19,27 @@ namespace SafeExamBrowser.Contracts.Communication.Proxies
 		/// <summary>
 		/// Retrieves the application configuration from the runtime.
 		/// </summary>
-		/// <exception cref="System.ServiceModel.*">If the communication failed.</exception>
+		CommunicationResult<ConfigurationResponse> GetConfiguration();
-		ClientConfiguration GetConfiguration();
 
 		/// <summary>
 		/// Informs the runtime that the client is ready.
 		/// </summary>
-		/// <exception cref="System.ServiceModel.*">If the communication failed.</exception>
+		CommunicationResult InformClientReady();
-		void InformClientReady();
 
 		/// <summary>
 		/// Requests the runtime to shut down the application.
 		/// </summary>
-		/// <exception cref="System.ServiceModel.*">If the communication failed.</exception>
+		CommunicationResult RequestShutdown();
-		void RequestShutdown();
 
 		/// <summary>
 		/// Requests the runtime to reconfigure the application with the specified configuration.
 		/// </summary>
-		/// <exception cref="System.ServiceModel.*">If the communication failed.</exception>
+		CommunicationResult RequestReconfiguration(string filePath);
-		void RequestReconfiguration(string filePath);
 
 		/// <summary>
 		/// Submits the result of a password input previously requested by the runtime. If the procedure was aborted by the user,
 		/// the password parameter will be <c>null</c>!
 		/// </summary>
-		/// /// <exception cref="System.ServiceModel.*">If the communication failed.</exception>
+		CommunicationResult SubmitPassword(Guid requestId, bool success, string password = null);
-		void SubmitPassword(Guid requestId, bool success, string password = null);
 	}
 }

SafeExamBrowser.Contracts/Communication/Proxies/IServiceProxy.cs

@@ -25,13 +25,11 @@ namespace SafeExamBrowser.Contracts.Communication.Proxies
 		/// <summary>
 		/// Instructs the service to start a new session according to the given parameters.
 		/// </summary>
-		/// <exception cref="System.ServiceModel.*">If the communication failed.</exception>
+		CommunicationResult StartSession(Guid sessionId, Settings settings);
-		void StartSession(Guid sessionId, Settings settings);
 
 		/// <summary>
 		/// Instructs the service to stop the specified session.
 		/// </summary>
-		/// <exception cref="System.ServiceModel.*">If the communication failed.</exception>
+		CommunicationResult StopSession(Guid sessionId);
-		void StopSession(Guid sessionId);
 	}
 }

SafeExamBrowser.Contracts/SafeExamBrowser.Contracts.csproj

@@ -75,6 +75,7 @@
     <Compile Include="Communication\Hosts\IHostObject.cs" />
     <Compile Include="Communication\Hosts\IHostObjectFactory.cs" />
     <Compile Include="Communication\ICommunication.cs" />
+    <Compile Include="Communication\Proxies\CommunicationResult.cs" />
     <Compile Include="Communication\Proxies\IClientProxy.cs" />
     <Compile Include="Communication\ICommunicationHost.cs" />
     <Compile Include="Communication\ICommunicationProxy.cs" />

SafeExamBrowser.Core.UnitTests/Communication/Proxies/BaseProxyTests.cs

@@ -106,14 +106,14 @@ namespace SafeExamBrowser.Core.UnitTests.Communication.Proxies
 		}
 
 		[TestMethod]
-		[ExpectedException(typeof(InvalidOperationException))]
 		public void MustFailToDisconnectIfNotConnected()
 		{
-			sut.Disconnect();
+			var success = sut.Disconnect();
+
+			Assert.IsFalse(success);
 		}
 
 		[TestMethod]
-		[ExpectedException(typeof(CommunicationException))]
 		public void MustFailToDisconnectIfChannelNotOpen()
 		{
 			var proxy = new Mock<IProxyObject>();
@@ -130,7 +130,10 @@ namespace SafeExamBrowser.Core.UnitTests.Communication.Proxies
 			var token = Guid.NewGuid();
 
 			sut.Connect(token);
-			sut.Disconnect();
+
+			var success = sut.Disconnect();
+
+			Assert.IsFalse(success);
 		}
 
 		[TestMethod]
@@ -141,7 +144,7 @@ namespace SafeExamBrowser.Core.UnitTests.Communication.Proxies
 		}
 
 		[TestMethod]
-		[ExpectedException(typeof(CommunicationException))]
+		[ExpectedException(typeof(InvalidOperationException))]
 		public void MustFailToSendIfChannelNotOpen()
 		{
 			var proxy = new Mock<IProxyObject>();

SafeExamBrowser.Core.UnitTests/Communication/Proxies/ClientProxyTests.cs

@@ -10,7 +10,6 @@ using System;
 using System.ServiceModel;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Moq;
-using SafeExamBrowser.Contracts.Communication;
 using SafeExamBrowser.Contracts.Communication.Data;
 using SafeExamBrowser.Contracts.Communication.Proxies;
 using SafeExamBrowser.Contracts.Logging;
@@ -52,18 +51,20 @@ namespace SafeExamBrowser.Core.UnitTests.Communication.Proxies
 		{
 			proxy.Setup(p => p.Send(It.Is<SimpleMessage>(m => m.Purport == SimpleMessagePurport.Shutdown))).Returns(new SimpleResponse(SimpleResponsePurport.Acknowledged));
 
-			sut.InitiateShutdown();
+			var communication = sut.InitiateShutdown();
 
 			proxy.Verify(p => p.Send(It.Is<SimpleMessage>(m => m.Purport == SimpleMessagePurport.Shutdown)), Times.Once);
+			Assert.IsTrue(communication.Success);
 		}
 
 		[TestMethod]
-		[ExpectedException(typeof(CommunicationException))]
+		public void MustIndicateIfShutdownCommandNotAcknowledged()
-		public void MustFailIfShutdownCommandNotAcknowledged()
 		{
 			proxy.Setup(p => p.Send(It.Is<SimpleMessage>(m => m.Purport == SimpleMessagePurport.Shutdown))).Returns<Response>(null);
 
-			sut.InitiateShutdown();
+			var communication = sut.InitiateShutdown();
+
+			Assert.IsFalse(communication.Success);
 		}
 
 		[TestMethod]
@@ -71,20 +72,24 @@ namespace SafeExamBrowser.Core.UnitTests.Communication.Proxies
 		{
 			proxy.Setup(p => p.Send(It.Is<SimpleMessage>(m => m.Purport == SimpleMessagePurport.Authenticate))).Returns(new AuthenticationResponse());
 
-			var response = sut.RequestAuthentication();
+			var communication = sut.RequestAuthentication();
+			var response = communication.Value;
 
 			proxy.Verify(p => p.Send(It.Is<SimpleMessage>(m => m.Purport == SimpleMessagePurport.Authenticate)), Times.Once);
 
+			Assert.IsTrue(communication.Success);
 			Assert.IsInstanceOfType(response, typeof(AuthenticationResponse));
 		}
 
 		[TestMethod]
-		[ExpectedException(typeof(CommunicationException))]
+		public void MustIndicateIfAuthenticationCommandNotAcknowledged()
-		public void MustFailIfAuthenticationCommandNotFollowed()
 		{
 			proxy.Setup(p => p.Send(It.Is<SimpleMessage>(m => m.Purport == SimpleMessagePurport.Authenticate))).Returns<Response>(null);
 
-			sut.RequestAuthentication();
+			var communication = sut.RequestAuthentication();
+
+			Assert.AreEqual(default(AuthenticationResponse), communication.Value);
+			Assert.IsFalse(communication.Success);
 		}
 	}
 }

SafeExamBrowser.Core.UnitTests/Communication/Proxies/RuntimeProxyTests.cs

@@ -57,20 +57,23 @@ namespace SafeExamBrowser.Core.UnitTests.Communication.Proxies
 
 			proxy.Setup(p => p.Send(It.Is<SimpleMessage>(m => m.Purport == SimpleMessagePurport.ConfigurationNeeded))).Returns(response);
 
-			var configuration = sut.GetConfiguration();
+			var communication = sut.GetConfiguration();
+			var configuration = communication.Value.Configuration;
 
 			proxy.Verify(p => p.Send(It.Is<SimpleMessage>(m => m.Purport == SimpleMessagePurport.ConfigurationNeeded)), Times.Once);
 
+			Assert.IsTrue(communication.Success);
 			Assert.IsInstanceOfType(configuration, typeof(ClientConfiguration));
 		}
 
 		[TestMethod]
-		[ExpectedException(typeof(CommunicationException))]
 		public void MustFailIfConfigurationNotRetrieved()
 		{
 			proxy.Setup(p => p.Send(It.Is<SimpleMessage>(m => m.Purport == SimpleMessagePurport.ConfigurationNeeded))).Returns<Response>(null);
 
-			sut.GetConfiguration();
+			var communication = sut.GetConfiguration();
+
+			Assert.IsFalse(communication.Success);
 		}
 
 		[TestMethod]
@@ -78,18 +81,20 @@ namespace SafeExamBrowser.Core.UnitTests.Communication.Proxies
 		{
 			proxy.Setup(p => p.Send(It.Is<SimpleMessage>(m => m.Purport == SimpleMessagePurport.ClientIsReady))).Returns(new SimpleResponse(SimpleResponsePurport.Acknowledged));
 
-			sut.InformClientReady();
+			var communication = sut.InformClientReady();
 
+			Assert.IsTrue(communication.Success);
 			proxy.Verify(p => p.Send(It.Is<SimpleMessage>(m => m.Purport == SimpleMessagePurport.ClientIsReady)), Times.Once);
 		}
 
 		[TestMethod]
-		[ExpectedException(typeof(CommunicationException))]
 		public void MustFailIfClientReadyNotAcknowledged()
 		{
 			proxy.Setup(p => p.Send(It.Is<SimpleMessage>(m => m.Purport == SimpleMessagePurport.ClientIsReady))).Returns<Response>(null);
 
-			sut.InformClientReady();
+			var communication = sut.InformClientReady();
+
+			Assert.IsFalse(communication.Success);
 		}
 
 		[TestMethod]
@@ -99,20 +104,22 @@ namespace SafeExamBrowser.Core.UnitTests.Communication.Proxies
 
 			proxy.Setup(p => p.Send(It.Is<ReconfigurationMessage>(m => m.ConfigurationPath == url))).Returns(new SimpleResponse(SimpleResponsePurport.Acknowledged));
 
-			sut.RequestReconfiguration(url);
+			var communication = sut.RequestReconfiguration(url);
 
+			Assert.IsTrue(communication.Success);
 			proxy.Verify(p => p.Send(It.Is<ReconfigurationMessage>(m => m.ConfigurationPath == url)), Times.Once);
 		}
 
 		[TestMethod]
-		[ExpectedException(typeof(CommunicationException))]
 		public void MustFailIfReconfigurationRequestNotAcknowledged()
 		{
 			var url = "file:///C:/Some/file/url.seb";
 
 			proxy.Setup(p => p.Send(It.Is<ReconfigurationMessage>(m => m.ConfigurationPath == url))).Returns<Response>(null);
 
-			sut.RequestReconfiguration(url);
+			var communication = sut.RequestReconfiguration(url);
+
+			Assert.IsFalse(communication.Success);
 		}
 
 		[TestMethod]
@@ -120,18 +127,20 @@ namespace SafeExamBrowser.Core.UnitTests.Communication.Proxies
 		{
 			proxy.Setup(p => p.Send(It.Is<SimpleMessage>(m => m.Purport == SimpleMessagePurport.RequestShutdown))).Returns(new SimpleResponse(SimpleResponsePurport.Acknowledged));
 
-			sut.RequestShutdown();
+			var communication = sut.RequestShutdown();
 
+			Assert.IsTrue(communication.Success);
 			proxy.Verify(p => p.Send(It.Is<SimpleMessage>(m => m.Purport == SimpleMessagePurport.RequestShutdown)), Times.Once);
 		}
 
 		[TestMethod]
-		[ExpectedException(typeof(CommunicationException))]
 		public void MustFailIfShutdownRequestNotAcknowledged()
 		{
 			proxy.Setup(p => p.Send(It.Is<SimpleMessage>(m => m.Purport == SimpleMessagePurport.RequestShutdown))).Returns<Response>(null);
 
-			sut.RequestShutdown();
+			var communication = sut.RequestShutdown();
+
+			Assert.IsFalse(communication.Success);
 		}
 	}
 }

SafeExamBrowser.Core.UnitTests/Communication/Proxies/ServiceProxyTests.cs

@@ -10,7 +10,6 @@ using System;
 using System.ServiceModel;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Moq;
-using SafeExamBrowser.Contracts.Communication;
 using SafeExamBrowser.Contracts.Communication.Data;
 using SafeExamBrowser.Contracts.Communication.Proxies;
 using SafeExamBrowser.Contracts.Logging;
@@ -68,8 +67,10 @@ namespace SafeExamBrowser.Core.UnitTests.Communication.Proxies
 		public void MustIgnoreStartSessionIfUnavaiable()
 		{
 			sut.Ignore = true;
-			sut.StartSession(Guid.Empty, null);
 
+			var communication = sut.StartSession(Guid.Empty, null);
+
+			Assert.IsTrue(communication.Success);
 			proxy.Verify(p => p.Send(It.IsAny<Message>()), Times.Never);
 		}
 
@@ -77,8 +78,10 @@ namespace SafeExamBrowser.Core.UnitTests.Communication.Proxies
 		public void MustIgnoreStopSessionIfUnavaiable()
 		{
 			sut.Ignore = true;
-			sut.StopSession(Guid.Empty);
 
+			var communication = sut.StopSession(Guid.Empty);
+
+			Assert.IsTrue(communication.Success);
 			proxy.Verify(p => p.Send(It.IsAny<Message>()), Times.Never);
 		}
 	}

SafeExamBrowser.Core/Communication/Proxies/BaseProxy.cs

@@ -31,6 +31,7 @@ namespace SafeExamBrowser.Core.Communication.Proxies
 		private Guid? communicationToken;
 		private Timer timer;
 
+		protected bool IsConnected { get { return communicationToken.HasValue; } }
 		protected ILogger Logger { get; private set; }
 
 		public event CommunicationEventHandler ConnectionLost;
@@ -43,51 +44,77 @@ namespace SafeExamBrowser.Core.Communication.Proxies
 		}
 
 		public virtual bool Connect(Guid? token = null, bool autoPing = true)
+		{
+			try
 			{
 				Logger.Debug($"Trying to connect to endpoint '{address}'{(token.HasValue ? $" with authentication token '{token}'" : string.Empty)}...");
 
 				InitializeProxyObject();
 
 				var response = proxy.Connect(token);
+				var success = response.ConnectionEstablished;
 
 				communicationToken = response.CommunicationToken;
-			Logger.Debug($"Connection was {(response.ConnectionEstablished ? "established" : "refused")}.");
+				Logger.Debug($"Connection was {(success ? "established" : "refused")}.");
 
-			if (response.ConnectionEstablished && autoPing)
+				if (success && autoPing)
 				{
 					StartAutoPing();
 				}
 
-			return response.ConnectionEstablished;
+				return success;
+			}
+			catch (Exception e)
+			{
+				Logger.Error($"Failed to connect to endpoint '{address}'!", e);
+
+				return false;
+			}
 		}
 
 		public virtual bool Disconnect()
 		{
-			FailIfNotConnected(nameof(Disconnect));
+			try
+			{
+				if (!IsConnected)
+				{
+					Logger.Warn($"Cannot disconnect from endpoint '{address}' before being connected!");
+
+					return false;
+				}
+
 				StopAutoPing();
 
 				var message = new DisconnectionMessage { CommunicationToken = communicationToken.Value };
 				var response = proxy.Disconnect(message);
+				var success = response.ConnectionTerminated;
 
-			Logger.Debug($"{(response.ConnectionTerminated ? "Disconnected" : "Failed to disconnect")} from {address}.");
+				Logger.Debug($"{(success ? "Disconnected" : "Failed to disconnect")} from {address}.");
 
-			return response.ConnectionTerminated;
+				if (success)
+				{
+					communicationToken = null;
+				}
+
+				return success;
+			}
+			catch (Exception e)
+			{
+				Logger.Error($"Failed to disconnect from endpoint '{address}'!", e);
+
+				return false;
+			}
 		}
 
 		/// <summary>
 		/// Sends the given message, optionally returning a response. If no response is expected, <c>null</c> will be returned.
 		/// </summary>
 		/// <exception cref="ArgumentNullException">If the given message is <c>null</c>.</exception>
-		/// <exception cref="InvalidOperationException">If no connection has been established yet.</exception>
+		/// <exception cref="InvalidOperationException">If no connection has been established yet or the connection is corrupted.</exception>
-		/// <exception cref="System.ServiceModel.*">If the communication failed.</exception>
 		protected virtual Response Send(Message message)
 		{
-			if (message is null)
+			FailIfNull(message);
-			{
+			FailIfNotConnected();
-				throw new ArgumentNullException(nameof(message));
-			}
-
-			FailIfNotConnected(nameof(Send));
 
 			message.CommunicationToken = communicationToken.Value;
 
@@ -195,16 +222,24 @@ namespace SafeExamBrowser.Core.Communication.Proxies
 			Logger.Debug("Communication channel is opening...");
 		}
 
-		private void FailIfNotConnected(string operationName)
+		private void FailIfNull(Message message)
 		{
-			if (!communicationToken.HasValue)
+			if (message is null)
 			{
-				throw new InvalidOperationException($"Cannot perform '{operationName}' before being connected to endpoint!");
+				throw new ArgumentNullException(nameof(message));
+			}
+		}
+
+		private void FailIfNotConnected()
+		{
+			if (!IsConnected)
+			{
+				throw new InvalidOperationException($"Cannot send message before being connected to endpoint '{address}'!");
 			}
 
 			if (proxy == null || proxy.State != CommunicationState.Opened)
 			{
-				throw new CommunicationException($"Tried to perform {operationName}, but channel was {GetChannelState()}!");
+				throw new InvalidOperationException($"Tried to send message, but channel was {GetChannelState()}!");
 			}
 		}
 

SafeExamBrowser.Core/Communication/Proxies/ClientProxy.cs

@@ -7,7 +7,6 @@
  */
 
 using System;
-using System.ServiceModel;
 using SafeExamBrowser.Contracts.Communication.Data;
 using SafeExamBrowser.Contracts.Communication.Proxies;
 using SafeExamBrowser.Contracts.Logging;
@@ -23,45 +22,107 @@ namespace SafeExamBrowser.Core.Communication.Proxies
 		{
 		}
 
-		public void InformReconfigurationDenied(string filePath)
+		public CommunicationResult InformReconfigurationDenied(string filePath)
+		{
+			try
 			{
 				var response = Send(new ReconfigurationDeniedMessage(filePath));
+				var success = IsAcknowledged(response);
 
-			if (!IsAcknowledged(response))
+				if (success)
 				{
-				throw new CommunicationException($"Client did not acknowledge shutdown request! Received: {ToString(response)}.");
+					Logger.Debug("Client acknowledged reconfiguration denial.");
+				}
+				else
+				{
+					Logger.Error($"Client did not acknowledge reconfiguration denial! Received: {ToString(response)}.");
+				}
+
+				return new CommunicationResult(success);
+			}
+			catch (Exception e)
+			{
+				Logger.Error($"Failed to perform '{nameof(InformReconfigurationDenied)}'", e);
+
+				return new CommunicationResult(false);
 			}
 		}
 
-		public void InitiateShutdown()
+		public CommunicationResult InitiateShutdown()
+		{
+			try
 			{
 				var response = Send(SimpleMessagePurport.Shutdown);
+				var success = IsAcknowledged(response);
 
-			if (!IsAcknowledged(response))
+				if (success)
 				{
-				throw new CommunicationException($"Client did not acknowledge shutdown request! Received: {ToString(response)}.");
+					Logger.Debug("Client acknowledged shutdown request.");
+				}
+				else
+				{
+					Logger.Error($"Client did not acknowledge shutdown request! Received: {ToString(response)}.");
+				}
+
+				return new CommunicationResult(success);
+			}
+			catch (Exception e)
+			{
+				Logger.Error($"Failed to perform '{nameof(InitiateShutdown)}'", e);
+
+				return new CommunicationResult(false);
 			}
 		}
 
-		public AuthenticationResponse RequestAuthentication()
+		public CommunicationResult<AuthenticationResponse> RequestAuthentication()
+		{
+			try
 			{
 				var response = Send(SimpleMessagePurport.Authenticate);
+				var success = response is AuthenticationResponse;
 
-			if (response is AuthenticationResponse authenticationResponse)
+				if (success)
 				{
-				return authenticationResponse;
+					Logger.Debug("Received authentication response.");
+				}
+				else
+				{
+					Logger.Error($"Did not receive authentication response! Received: {ToString(response)}.");
 				}
 
-			throw new CommunicationException($"Did not receive authentication response! Received: {ToString(response)}.");
+				return new CommunicationResult<AuthenticationResponse>(success, response as AuthenticationResponse);
+			}
+			catch (Exception e)
+			{
+				Logger.Error($"Failed to perform '{nameof(RequestAuthentication)}'", e);
+
+				return new CommunicationResult<AuthenticationResponse>(false, default(AuthenticationResponse));
+			}
 		}
 
-		public void RequestPassword(PasswordRequestPurpose purpose, Guid requestId)
+		public CommunicationResult RequestPassword(PasswordRequestPurpose purpose, Guid requestId)
+		{
+			try
 			{
 				var response = Send(new PasswordRequestMessage(purpose, requestId));
+				var success = IsAcknowledged(response);
 
-			if (!IsAcknowledged(response))
+				if (success)
 				{
-				throw new CommunicationException($"Client did not acknowledge shutdown request! Received: {ToString(response)}.");
+					Logger.Debug("Client acknowledged password request.");
+				}
+				else
+				{
+					Logger.Error($"Client did not acknowledge password request! Received: {ToString(response)}.");
+				}
+
+				return new CommunicationResult(success);
+			}
+			catch (Exception e)
+			{
+				Logger.Error($"Failed to perform '{nameof(RequestPassword)}'", e);
+
+				return new CommunicationResult(false);
 			}
 		}
 	}

SafeExamBrowser.Core/Communication/Proxies/RuntimeProxy.cs

@@ -7,10 +7,8 @@
  */
 
 using System;
-using System.ServiceModel;
 using SafeExamBrowser.Contracts.Communication.Data;
 using SafeExamBrowser.Contracts.Communication.Proxies;
-using SafeExamBrowser.Contracts.Configuration;
 using SafeExamBrowser.Contracts.Logging;
 
 namespace SafeExamBrowser.Core.Communication.Proxies
@@ -24,55 +22,133 @@ namespace SafeExamBrowser.Core.Communication.Proxies
 		{
 		}
 
-		public ClientConfiguration GetConfiguration()
+		public CommunicationResult<ConfigurationResponse> GetConfiguration()
+		{
+			try
 			{
 				var response = Send(SimpleMessagePurport.ConfigurationNeeded);
+				var success = response is ConfigurationResponse;
 
-			if (response is ConfigurationResponse configurationResponse)
+				if (success)
 				{
-				return configurationResponse.Configuration;
+					Logger.Debug("Received configuration response.");
+				}
+				else
+				{
+					Logger.Error($"Did not retrieve configuration response! Received: {ToString(response)}.");
 				}
 
-			throw new CommunicationException($"Could not retrieve client configuration! Received: {ToString(response)}.");
+				return new CommunicationResult<ConfigurationResponse>(success, response as ConfigurationResponse);
+			}
+			catch (Exception e)
+			{
+				Logger.Error($"Failed to perform '{nameof(GetConfiguration)}'", e);
+
+				return new CommunicationResult<ConfigurationResponse>(false, default(ConfigurationResponse));
+			}
 		}
 
-		public void InformClientReady()
+		public CommunicationResult InformClientReady()
+		{
+			try
 			{
 				var response = Send(SimpleMessagePurport.ClientIsReady);
+				var success = IsAcknowledged(response);
 
-			if (!IsAcknowledged(response))
+				if (success)
 				{
-				throw new CommunicationException($"Runtime did not acknowledge that client is ready! Response: {ToString(response)}.");
+					Logger.Debug("Runtime acknowledged that the client is ready.");
+				}
+				else
+				{
+					Logger.Error($"Runtime did not acknowledge that the client is ready! Response: {ToString(response)}.");
+				}
+
+				return new CommunicationResult(success);
+			}
+			catch (Exception e)
+			{
+				Logger.Error($"Failed to perform '{nameof(InformClientReady)}'", e);
+
+				return new CommunicationResult(false);
 			}
 		}
 
-		public void RequestReconfiguration(string filePath)
+		public CommunicationResult RequestReconfiguration(string filePath)
+		{
+			try
 			{
 				var response = Send(new ReconfigurationMessage(filePath));
+				var success = IsAcknowledged(response);
 
-			if (!IsAcknowledged(response))
+				if (success)
 				{
-				throw new CommunicationException($"Runtime did not acknowledge reconfiguration request! Response: {ToString(response)}.");
+					Logger.Debug("Runtime acknowledged reconfiguration request.");
+				}
+				else
+				{
+					Logger.Error($"Runtime did not acknowledge reconfiguration request! Response: {ToString(response)}.");
+				}
+
+				return new CommunicationResult(success);
+			}
+			catch (Exception e)
+			{
+				Logger.Error($"Failed to perform '{nameof(RequestReconfiguration)}'", e);
+
+				return new CommunicationResult(false);
 			}
 		}
 
-		public void RequestShutdown()
+		public CommunicationResult RequestShutdown()
+		{
+			try
 			{
 				var response = Send(SimpleMessagePurport.RequestShutdown);
+				var success = IsAcknowledged(response);
 
-			if (!IsAcknowledged(response))
+				if (success)
 				{
-				throw new CommunicationException($"Runtime did not acknowledge shutdown request! Response: {ToString(response)}.");
+					Logger.Debug("Runtime acknowledged shutdown request.");
+				}
+				else
+				{
+					Logger.Error($"Runtime did not acknowledge shutdown request! Response: {ToString(response)}.");
+				}
+
+				return new CommunicationResult(success);
+			}
+			catch (Exception e)
+			{
+				Logger.Error($"Failed to perform '{nameof(RequestShutdown)}'", e);
+
+				return new CommunicationResult(false);
 			}
 		}
 
-		public void SubmitPassword(Guid requestId, bool success, string password = null)
+		public CommunicationResult SubmitPassword(Guid requestId, bool success, string password = null)
+		{
+			try
 			{
 				var response = Send(new PasswordReplyMessage(requestId, success, password));
+				var acknowledged = IsAcknowledged(response);
 
-			if (!IsAcknowledged(response))
+				if (acknowledged)
 				{
-				throw new CommunicationException($"Runtime did not acknowledge password submission! Response: {ToString(response)}.");
+					Logger.Debug("Runtime acknowledged password transmission.");
+				}
+				else
+				{
+					Logger.Error($"Runtime did not acknowledge password transmission! Response: {ToString(response)}.");
+				}
+
+				return new CommunicationResult(acknowledged);
+			}
+			catch (Exception e)
+			{
+				Logger.Error($"Failed to perform '{nameof(SubmitPassword)}'", e);
+
+				return new CommunicationResult(false);
 			}
 		}
 	}

SafeExamBrowser.Core/Communication/Proxies/ServiceProxy.cs

@@ -38,32 +38,36 @@ namespace SafeExamBrowser.Core.Communication.Proxies
 		{
 			if (IgnoreOperation(nameof(Disconnect)))
 			{
-				return true;
+				return false;
 			}
 
 			return base.Disconnect();
 		}
 
-		public void StartSession(Guid sessionId, Settings settings)
+		public CommunicationResult StartSession(Guid sessionId, Settings settings)
 		{
 			if (IgnoreOperation(nameof(StartSession)))
 			{
-				return;
+				return new CommunicationResult(true);
 			}
 
 			// TODO: Implement service communication
 			// Send(new StartSessionMessage { Id = sessionId, Settings = settings });
+
+			throw new NotImplementedException();
 		}
 
-		public void StopSession(Guid sessionId)
+		public CommunicationResult StopSession(Guid sessionId)
 		{
 			if (IgnoreOperation(nameof(StopSession)))
 			{
-				return;
+				return new CommunicationResult(true);
 			}
 
 			// TODO: Implement service communication
 			// Send(new StopSessionMessage { SessionId = sessionId });
+
+			throw new NotImplementedException();
 		}
 
 		private bool IgnoreOperation(string operationName)

SafeExamBrowser.Runtime.UnitTests/Behaviour/Operations/ClientOperationTests.cs

@@ -67,10 +67,11 @@ namespace SafeExamBrowser.Runtime.UnitTests.Behaviour.Operations
 		{
 			var result = default(OperationResult);
 			var response = new AuthenticationResponse { ProcessId = 1234 };
+			var communication = new CommunicationResult<AuthenticationResponse>(true, response);
 
 			process.SetupGet(p => p.Id).Returns(response.ProcessId);
 			processFactory.Setup(f => f.StartNew(It.IsAny<string>(), It.IsAny<string[]>())).Returns(process.Object).Callback(clientReady);
-			proxy.Setup(p => p.RequestAuthentication()).Returns(response);
+			proxy.Setup(p => p.RequestAuthentication()).Returns(communication);
 			proxy.Setup(p => p.Connect(It.IsAny<Guid>(), true)).Returns(true);
 
 			result = sut.Perform();
@@ -86,10 +87,11 @@ namespace SafeExamBrowser.Runtime.UnitTests.Behaviour.Operations
 		{
 			var result = default(OperationResult);
 			var response = new AuthenticationResponse { ProcessId = 1234 };
+			var communication = new CommunicationResult<AuthenticationResponse>(true, response);
 
 			process.SetupGet(p => p.Id).Returns(response.ProcessId);
 			processFactory.Setup(f => f.StartNew(It.IsAny<string>(), It.IsAny<string[]>())).Returns(process.Object).Callback(clientReady);
-			proxy.Setup(p => p.RequestAuthentication()).Returns(response);
+			proxy.Setup(p => p.RequestAuthentication()).Returns(communication);
 			proxy.Setup(p => p.Connect(It.IsAny<Guid>(), true)).Returns(true);
 
 			result = sut.Repeat();
@@ -134,10 +136,11 @@ namespace SafeExamBrowser.Runtime.UnitTests.Behaviour.Operations
 		{
 			var result = default(OperationResult);
 			var response = new AuthenticationResponse { ProcessId = -1 };
+			var communication = new CommunicationResult<AuthenticationResponse>(true, response);
 
 			process.SetupGet(p => p.Id).Returns(1234);
 			processFactory.Setup(f => f.StartNew(It.IsAny<string>(), It.IsAny<string[]>())).Returns(process.Object).Callback(clientReady);
-			proxy.Setup(p => p.RequestAuthentication()).Returns(response);
+			proxy.Setup(p => p.RequestAuthentication()).Returns(communication);
 			proxy.Setup(p => p.Connect(It.IsAny<Guid>(), true)).Returns(true);
 
 			result = sut.Perform();
@@ -204,10 +207,11 @@ namespace SafeExamBrowser.Runtime.UnitTests.Behaviour.Operations
 		private void PerformNormally()
 		{
 			var response = new AuthenticationResponse { ProcessId = 1234 };
+			var communication = new CommunicationResult<AuthenticationResponse>(true, response);
 
 			process.SetupGet(p => p.Id).Returns(response.ProcessId);
 			processFactory.Setup(f => f.StartNew(It.IsAny<string>(), It.IsAny<string[]>())).Returns(process.Object).Callback(clientReady);
-			proxy.Setup(p => p.RequestAuthentication()).Returns(response);
+			proxy.Setup(p => p.RequestAuthentication()).Returns(communication);
 			proxy.Setup(p => p.Connect(It.IsAny<Guid>(), true)).Returns(true);
 
 			sut.Perform();

SafeExamBrowser.Runtime.UnitTests/Behaviour/Operations/ConfigurationOperationTests.cs

@@ -335,6 +335,7 @@ namespace SafeExamBrowser.Runtime.UnitTests.Behaviour.Operations
 		public void MustRequestPasswordViaClientDuringReconfigurationOnNewDesktop()
 		{
 			var clientProxy = new Mock<IClientProxy>();
+			var communication = new CommunicationResult(true);
 			var passwordReceived = new Action<PasswordRequestPurpose, Guid>((p, id) =>
 			{
 				runtimeHost.Raise(r => r.PasswordReceived += null, new PasswordReplyEventArgs { RequestId = id, Success = true });
@@ -342,7 +343,7 @@ namespace SafeExamBrowser.Runtime.UnitTests.Behaviour.Operations
 			var session = new Mock<ISessionData>();
 			var url = @"http://www.safeexambrowser.org/whatever.seb";
 
-			clientProxy.Setup(c => c.RequestPassword(It.IsAny<PasswordRequestPurpose>(), It.IsAny<Guid>())).Callback(passwordReceived);
+			clientProxy.Setup(c => c.RequestPassword(It.IsAny<PasswordRequestPurpose>(), It.IsAny<Guid>())).Returns(communication).Callback(passwordReceived);
 			passwordDialog.Setup(d => d.Show(null)).Returns(new PasswordDialogResultStub { Success = true });
 			repository.SetupGet(r => r.CurrentSession).Returns(session.Object);
 			repository.Setup(r => r.LoadSettings(It.IsAny<Uri>(), null, null)).Returns(LoadStatus.SettingsPasswordNeeded);
@@ -361,6 +362,7 @@ namespace SafeExamBrowser.Runtime.UnitTests.Behaviour.Operations
 		public void MustAbortAskingForPasswordViaClientIfDecidedByUser()
 		{
 			var clientProxy = new Mock<IClientProxy>();
+			var communication = new CommunicationResult(true);
 			var passwordReceived = new Action<PasswordRequestPurpose, Guid>((p, id) =>
 			{
 				runtimeHost.Raise(r => r.PasswordReceived += null, new PasswordReplyEventArgs { RequestId = id, Success = false });
@@ -368,8 +370,28 @@ namespace SafeExamBrowser.Runtime.UnitTests.Behaviour.Operations
 			var session = new Mock<ISessionData>();
 			var url = @"http://www.safeexambrowser.org/whatever.seb";
 
-			clientProxy.Setup(c => c.RequestPassword(It.IsAny<PasswordRequestPurpose>(), It.IsAny<Guid>())).Callback(passwordReceived);
+			clientProxy.Setup(c => c.RequestPassword(It.IsAny<PasswordRequestPurpose>(), It.IsAny<Guid>())).Returns(communication).Callback(passwordReceived);
-			passwordDialog.Setup(d => d.Show(null)).Returns(new PasswordDialogResultStub { Success = true });
+			repository.SetupGet(r => r.CurrentSession).Returns(session.Object);
+			repository.Setup(r => r.LoadSettings(It.IsAny<Uri>(), null, null)).Returns(LoadStatus.SettingsPasswordNeeded);
+			session.SetupGet(r => r.ClientProxy).Returns(clientProxy.Object);
+			settings.KioskMode = KioskMode.CreateNewDesktop;
+
+			sut = new ConfigurationOperation(appConfig, repository.Object, logger.Object, messageBox.Object, resourceLoader.Object, runtimeHost.Object, text.Object, uiFactory.Object, new[] { "blubb.exe", url });
+
+			var result = sut.Perform();
+
+			Assert.AreEqual(OperationResult.Aborted, result);
+		}
+
+		[TestMethod]
+		public void MustNotWaitForPasswordViaClientIfCommunicationHasFailed()
+		{
+			var clientProxy = new Mock<IClientProxy>();
+			var communication = new CommunicationResult(false);
+			var session = new Mock<ISessionData>();
+			var url = @"http://www.safeexambrowser.org/whatever.seb";
+
+			clientProxy.Setup(c => c.RequestPassword(It.IsAny<PasswordRequestPurpose>(), It.IsAny<Guid>())).Returns(communication);
 			repository.SetupGet(r => r.CurrentSession).Returns(session.Object);
 			repository.Setup(r => r.LoadSettings(It.IsAny<Uri>(), null, null)).Returns(LoadStatus.SettingsPasswordNeeded);
 			session.SetupGet(r => r.ClientProxy).Returns(clientProxy.Object);

SafeExamBrowser.Runtime.UnitTests/Behaviour/Operations/ServiceOperationTests.cs

@@ -97,16 +97,6 @@ namespace SafeExamBrowser.Runtime.UnitTests.Behaviour.Operations
 			configuration.SetupGet(s => s.CurrentSettings).Returns(new Settings { ServicePolicy = ServicePolicy.Optional });
 
 			sut.Perform();
-
-			service.Setup(s => s.Connect(null, true)).Throws<Exception>();
-			configuration.SetupGet(s => s.CurrentSettings).Returns(new Settings { ServicePolicy = ServicePolicy.Mandatory });
-
-			sut.Perform();
-
-			service.Setup(s => s.Connect(null, true)).Throws<Exception>();
-			configuration.SetupGet(s => s.CurrentSettings).Returns(new Settings { ServicePolicy = ServicePolicy.Optional });
-
-			sut.Perform();
 		}
 
 		[TestMethod]
@@ -177,7 +167,7 @@ namespace SafeExamBrowser.Runtime.UnitTests.Behaviour.Operations
 		public void MustNotFailWhenDisconnecting()
 		{
 			service.Setup(s => s.Connect(null, true)).Returns(true);
-			service.Setup(s => s.Disconnect()).Throws<Exception>();
+			service.Setup(s => s.Disconnect()).Returns(false);
 			configuration.SetupGet(s => s.CurrentSettings).Returns(new Settings { ServicePolicy = ServicePolicy.Optional });
 
 			sut.Perform();
@@ -201,18 +191,6 @@ namespace SafeExamBrowser.Runtime.UnitTests.Behaviour.Operations
 			sut.Perform();
 			sut.Revert();
 
-			service.Setup(s => s.Connect(null, true)).Throws<Exception>();
-			configuration.SetupGet(s => s.CurrentSettings).Returns(new Settings { ServicePolicy = ServicePolicy.Mandatory });
-
-			sut.Perform();
-			sut.Revert();
-
-			service.Setup(s => s.Connect(null, true)).Throws<Exception>();
-			configuration.SetupGet(s => s.CurrentSettings).Returns(new Settings { ServicePolicy = ServicePolicy.Optional });
-
-			sut.Perform();
-			sut.Revert();
-
 			service.Verify(s => s.Disconnect(), Times.Never);
 		}
 	}

SafeExamBrowser.Runtime/Behaviour/Operations/ClientOperation.cs

@@ -120,9 +120,10 @@ namespace SafeExamBrowser.Runtime.Behaviour.Operations
 
 			logger.Info("Connection with client has been established. Requesting authentication...");
 
-			var response = ClientProxy.RequestAuthentication();
+			var communication = ClientProxy.RequestAuthentication();
+			var response = communication.Value;
 
-			if (ClientProcess.Id != response?.ProcessId)
+			if (!communication.Success || ClientProcess.Id != response?.ProcessId)
 			{
 				logger.Error("Failed to verify client integrity!");
 

SafeExamBrowser.Runtime/Behaviour/Operations/ConfigurationOperation.cs

@@ -172,17 +172,11 @@ namespace SafeExamBrowser.Runtime.Behaviour.Operations
 			var title = isAdmin ? TextKey.PasswordDialog_AdminPasswordRequiredTitle : TextKey.PasswordDialog_SettingsPasswordRequiredTitle;
 			var dialog = uiFactory.CreatePasswordDialog(text.Get(message), text.Get(title));
 			var result = dialog.Show();
+			var success = result.Success;
 
-			if (result.Success)
+			password = success ? result.Password : default(string);
-			{
-				password = result.Password;
-			}
-			else
-			{
-				password = default(string);
-			}
 
-			return result.Success;
+			return success;
 		}
 
 		private bool TryGetPasswordViaClient(PasswordRequestPurpose purpose, out string password)
@@ -200,20 +194,20 @@ namespace SafeExamBrowser.Runtime.Behaviour.Operations
 			});
 
 			runtimeHost.PasswordReceived += responseEventHandler;
-			configuration.CurrentSession.ClientProxy.RequestPassword(purpose, requestId);
+
+			var communication = configuration.CurrentSession.ClientProxy.RequestPassword(purpose, requestId);
+
+			if (communication.Success)
+			{
 				responseEvent.WaitOne();
+			}
+
+			var success = response?.Success == true;
+
 			runtimeHost.PasswordReceived -= responseEventHandler;
+			password = success ? response.Password : default(string);
 
-			if (response.Success)
+			return success;
-			{
-				password = response.Password;
-			}
-			else
-			{
-				password = default(string);
-			}
-
-			return response.Success;
 		}
 
 		private void HandleInvalidData(ref LoadStatus status, Uri uri)

SafeExamBrowser.Runtime/Behaviour/Operations/ServiceOperation.cs

@@ -6,7 +6,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-using System;
 using SafeExamBrowser.Contracts.Behaviour.OperationModel;
 using SafeExamBrowser.Contracts.Communication.Proxies;
 using SafeExamBrowser.Contracts.Configuration;
@@ -40,15 +39,8 @@ namespace SafeExamBrowser.Runtime.Behaviour.Operations
 			logger.Info($"Initializing service session...");
 			ProgressIndicator?.UpdateText(TextKey.ProgressIndicator_InitializeServiceSession);
 
-			try
-			{
 			mandatory = configuration.CurrentSettings.ServicePolicy == ServicePolicy.Mandatory;
 			connected = service.Connect();
-			}
-			catch (Exception e)
-			{
-				LogException(e);
-			}
 
 			if (mandatory && !connected)
 			{
@@ -89,13 +81,15 @@ namespace SafeExamBrowser.Runtime.Behaviour.Operations
 			{
 				StopServiceSession();
 
-				try
+				var success = service.Disconnect();
+
+				if (success)
 				{
-					service.Disconnect();
+					logger.Info("Successfully disconnected from the service.");
 				}
-				catch (Exception e)
+				else
 				{
-					logger.Error("Failed to disconnect from the service!", e);
+					logger.Error("Failed to disconnect from the service!");
 				}
 			}
 		}
@@ -109,19 +103,5 @@ namespace SafeExamBrowser.Runtime.Behaviour.Operations
 		{
 			service.StopSession(configuration.CurrentSession.Id);
 		}
-
-		private void LogException(Exception e)
-		{
-			var message = "Failed to connect to the service component!";
-
-			if (mandatory)
-			{
-				logger.Error(message, e);
-			}
-			else
-			{
-				logger.Info($"{message} Reason: {e.Message}");
-			}
-		}
 	}
 }