108 lines
3.7 KiB
C#
108 lines
3.7 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.Threading.Tasks;
|
|
using SafeExamBrowser.Contracts.Communication;
|
|
using SafeExamBrowser.Contracts.Communication.Messages;
|
|
using SafeExamBrowser.Contracts.Communication.Responses;
|
|
using SafeExamBrowser.Contracts.Configuration;
|
|
using SafeExamBrowser.Contracts.Configuration.Settings;
|
|
using SafeExamBrowser.Contracts.Logging;
|
|
using SafeExamBrowser.Core.Communication;
|
|
|
|
namespace SafeExamBrowser.Runtime.Communication
|
|
{
|
|
internal class RuntimeHost : BaseHost, IRuntimeHost
|
|
{
|
|
private bool allowConnection = true;
|
|
private IConfigurationRepository configuration;
|
|
|
|
public Guid StartupToken { private get; set; }
|
|
|
|
public event CommunicationEventHandler ClientDisconnected;
|
|
public event CommunicationEventHandler ClientReady;
|
|
public event CommunicationEventHandler ReconfigurationRequested;
|
|
public event CommunicationEventHandler ShutdownRequested;
|
|
|
|
public RuntimeHost(string address, IConfigurationRepository configuration, ILogger logger) : base(address, logger)
|
|
{
|
|
this.configuration = configuration;
|
|
}
|
|
|
|
protected override bool OnConnect(Guid? token = null)
|
|
{
|
|
var authenticated = StartupToken == token;
|
|
var accepted = allowConnection && authenticated;
|
|
|
|
if (accepted)
|
|
{
|
|
allowConnection = false;
|
|
}
|
|
|
|
return accepted;
|
|
}
|
|
|
|
protected override void OnDisconnect()
|
|
{
|
|
ClientDisconnected?.Invoke();
|
|
// TODO: Handle client crash scenario!
|
|
// If a client crashes or hangs when terminating (which should not happen!), it could be that it never gets to disconnect from
|
|
// the RuntimeHost - in that case, allowConnection prohibits restarting a new session as long as it's only set here!
|
|
// -> Move AllowConnection to interface and reset it in SessionController?
|
|
// -> Only possible as long as just the client connects, with service and client a more elaborate solution will be needed!
|
|
// -> E.g. ClientId and ServiceId, and then AllowClientConnection and AllowServiceConnection?
|
|
allowConnection = true;
|
|
}
|
|
|
|
protected override Response OnReceive(Message message)
|
|
{
|
|
switch (message)
|
|
{
|
|
case ReconfigurationMessage reconfigurationMessage:
|
|
return Handle(reconfigurationMessage);
|
|
}
|
|
|
|
return new SimpleResponse(SimpleResponsePurport.UnknownMessage);
|
|
}
|
|
|
|
protected override Response OnReceive(SimpleMessagePurport message)
|
|
{
|
|
switch (message)
|
|
{
|
|
case SimpleMessagePurport.ClientIsReady:
|
|
ClientReady?.Invoke();
|
|
return new SimpleResponse(SimpleResponsePurport.Acknowledged);
|
|
case SimpleMessagePurport.ConfigurationNeeded:
|
|
return new ConfigurationResponse { Configuration = configuration.BuildClientConfiguration() };
|
|
case SimpleMessagePurport.RequestShutdown:
|
|
ShutdownRequested?.Invoke();
|
|
return new SimpleResponse(SimpleResponsePurport.Acknowledged);
|
|
}
|
|
|
|
return new SimpleResponse(SimpleResponsePurport.UnknownMessage);
|
|
}
|
|
|
|
private Response Handle(ReconfigurationMessage message)
|
|
{
|
|
var isExam = configuration.CurrentSettings.ConfigurationMode == ConfigurationMode.Exam;
|
|
var isValidUri = Uri.TryCreate(message.ConfigurationUrl, UriKind.Absolute, out _);
|
|
var allowed = !isExam && isValidUri;
|
|
|
|
Logger.Info($"Received reconfiguration request for '{message.ConfigurationUrl}', {(allowed ? "accepted" : "denied")} it.");
|
|
|
|
if (allowed)
|
|
{
|
|
configuration.ReconfigurationUrl = message.ConfigurationUrl;
|
|
Task.Run(() => ReconfigurationRequested?.Invoke());
|
|
}
|
|
|
|
return new ReconfigurationResponse { Accepted = allowed };
|
|
}
|
|
}
|
|
}
|