Restore SEBPatch

SafeExamBrowser.Service/Communication/ServiceHost.cs

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2024 ETH Zürich, IT Services
+ *
+ * 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 SafeExamBrowser.Communication.Hosts;
+using SafeExamBrowser.Communication.Contracts;
+using SafeExamBrowser.Communication.Contracts.Data;
+using SafeExamBrowser.Communication.Contracts.Events;
+using SafeExamBrowser.Communication.Contracts.Hosts;
+using SafeExamBrowser.Logging.Contracts;
+
+namespace SafeExamBrowser.Service.Communication
+{
+	internal class ServiceHost : BaseHost, IServiceHost
+	{
+		private bool allowConnection;
+
+		public event CommunicationEventHandler<SessionStartEventArgs> SessionStartRequested;
+		public event CommunicationEventHandler<SessionStopEventArgs> SessionStopRequested;
+		public event CommunicationEventHandler SystemConfigurationUpdateRequested;
+
+		internal ServiceHost(string address, IHostObjectFactory factory, ILogger logger, int timeout_ms) : base(address, factory, logger, timeout_ms)
+		{
+			allowConnection = true;
+		}
+
+		protected override bool OnConnect(Guid? token)
+		{
+			var allow = allowConnection;
+
+			if (allow)
+			{
+				allowConnection = false;
+			}
+
+			return allow;
+		}
+
+		protected override void OnDisconnect(Interlocutor interlocutor)
+		{
+			if (interlocutor == Interlocutor.Runtime)
+			{
+				allowConnection = true;
+			}
+		}
+
+		protected override Response OnReceive(Message message)
+		{
+			switch (message)
+			{
+				case SessionStartMessage m:
+					SessionStartRequested?.InvokeAsync(new SessionStartEventArgs { Configuration = m.Configuration });
+					return new SimpleResponse(SimpleResponsePurport.Acknowledged);
+				case SessionStopMessage m:
+					SessionStopRequested?.InvokeAsync(new SessionStopEventArgs { SessionId = m.SessionId });
+					return new SimpleResponse(SimpleResponsePurport.Acknowledged);
+			}
+
+			return new SimpleResponse(SimpleResponsePurport.UnknownMessage);
+		}
+
+		protected override Response OnReceive(SimpleMessagePurport message)
+		{
+			switch (message)
+			{
+				case SimpleMessagePurport.UpdateSystemConfiguration:
+					SystemConfigurationUpdateRequested?.InvokeAsync();
+					return new SimpleResponse(SimpleResponsePurport.Acknowledged);
+			}
+
+			return new SimpleResponse(SimpleResponsePurport.UnknownMessage);
+		}
+	}
+}