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SEBWIN-405: Changed implementation for sending of log events and implemented server quit event.

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This commit is contained in:
Damian Büchel 2020-08-01 17:55:18 +02:00
parent 6997d3a5f5
commit 09fbc6579a
6 changed files with 104 additions and 28 deletions
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10
SafeExamBrowser.Client/ClientController.cs
View file

@ -206,7 +206,7 @@ namespace SafeExamBrowser.Client
if (Server != null)
{
// TODO
Server.TerminationRequested += Server_TerminationRequested;
}
}
@ -240,7 +240,7 @@ namespace SafeExamBrowser.Client
if (Server != null)
{
// TODO
Server.TerminationRequested -= Server_TerminationRequested;
}
foreach (var activator in context.Activators.OfType<ITerminationActivator>())
@ -551,6 +551,12 @@ namespace SafeExamBrowser.Client
shutdown.Invoke();
}
private void Server_TerminationRequested()
{
logger.Info("Attempting to shutdown as requested by the server...");
TryRequestShutdown();
}
private void Shell_QuitButtonClicked(System.ComponentModel.CancelEventArgs args)
{
PauseActivators();

1
SafeExamBrowser.Runtime/Operations/ServerOperation.cs
View file

@ -77,6 +77,7 @@ namespace SafeExamBrowser.Runtime.Operations
if (status == LoadStatus.Success)
{
// TODO: Why aren't the server settings and SEB mode correctly set in the exam configuration?
var serverSettings = Context.Next.Settings.Server;
Context.Next.AppConfig.ServerApi = info.Api;

15
SafeExamBrowser.Server.Contracts/Events/TerminationRequestedEventHandler.cs Normal file
View file

@ -0,0 +1,15 @@
/*
* Copyright (c) 2020 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.Server.Contracts.Events
{
/// <summary>
/// Event handler used to indicate that a termination instruction has been detected.
/// </summary>
public delegate void TerminationRequestedEventHandler();
}

6
SafeExamBrowser.Server.Contracts/IServerProxy.cs
View file

@ -9,6 +9,7 @@
using System;
using System.Collections.Generic;
using SafeExamBrowser.Server.Contracts.Data;
using SafeExamBrowser.Server.Contracts.Events;
using SafeExamBrowser.Settings.Server;
namespace SafeExamBrowser.Server.Contracts
@ -18,6 +19,11 @@ namespace SafeExamBrowser.Server.Contracts
/// </summary>
public interface IServerProxy
{
/// <summary>
/// Event fired when the server detects an instruction to terminate SEB.
/// </summary>
event TerminationRequestedEventHandler TerminationRequested;
/// <summary>
/// Attempts to initialize a connection with the server.
/// </summary>

2
SafeExamBrowser.Server.Contracts/SafeExamBrowser.Server.Contracts.csproj
View file

@ -56,6 +56,7 @@
<ItemGroup>
<Compile Include="Data\ConnectionInfo.cs" />
<Compile Include="Data\Exam.cs" />
<Compile Include="Events\TerminationRequestedEventHandler.cs" />
<Compile Include="IServerProxy.cs" />
<Compile Include="Properties\AssemblyInfo.cs" />
<Compile Include="Data\ServerResponse.cs" />
@ -66,5 +67,6 @@
<Name>SafeExamBrowser.Settings</Name>
</ProjectReference>
</ItemGroup>
<ItemGroup />
<Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
</Project>

88
SafeExamBrowser.Server/ServerProxy.cs
View file

@ -14,6 +14,7 @@ using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Timers;
using Newtonsoft.Json;
@ -22,9 +23,11 @@ using SafeExamBrowser.Configuration.Contracts;
using SafeExamBrowser.Logging.Contracts;
using SafeExamBrowser.Server.Contracts;
using SafeExamBrowser.Server.Contracts.Data;
using SafeExamBrowser.Server.Contracts.Events;
using SafeExamBrowser.Server.Data;
using SafeExamBrowser.Settings.Logging;
using SafeExamBrowser.Settings.Server;
using Timer = System.Timers.Timer;
namespace SafeExamBrowser.Server
{
@ -32,6 +35,7 @@ namespace SafeExamBrowser.Server
{
private ApiVersion1 api;
private AppConfig appConfig;
private CancellationTokenSource cancellationTokenSource;
private string connectionToken;
private string examId;
private HttpClient httpClient;
@ -40,12 +44,16 @@ namespace SafeExamBrowser.Server
private string oauth2Token;
private int pingNumber;
private ServerSettings settings;
private Task task;
private Timer timer;
public event TerminationRequestedEventHandler TerminationRequested;
public ServerProxy(AppConfig appConfig, ILogger logger)
{
this.api = new ApiVersion1();
this.appConfig = appConfig;
this.cancellationTokenSource = new CancellationTokenSource();
this.httpClient = new HttpClient();
this.logger = logger;
this.logContent = new ConcurrentQueue<ILogContent>();
@ -244,6 +252,9 @@ namespace SafeExamBrowser.Server
logger.Subscribe(this);
task = new Task(SendLog, cancellationTokenSource.Token);
task.Start();
timer.AutoReset = false;
timer.Elapsed += Timer_Elapsed;
timer.Interval = 1000;
@ -253,36 +264,23 @@ namespace SafeExamBrowser.Server
public void StopConnectivity()
{
logger.Unsubscribe(this);
cancellationTokenSource.Cancel();
task.Wait();
timer.Stop();
timer.Elapsed -= Timer_Elapsed;
}
private void Timer_Elapsed(object sender, ElapsedEventArgs args)
private void SendLog()
{
var authorization = ("Authorization", $"Bearer {oauth2Token}");
var contentType = "application/json;charset=UTF-8";
var token = ("SEBConnectionToken", connectionToken);
try
{
var content = $"timestamp={DateTime.Now.Ticks}&ping-number={++pingNumber}";
var contentType = "application/x-www-form-urlencoded";
var success = TryExecute(HttpMethod.Post, api.PingEndpoint, out var response, content, contentType, authorization, token);
logger.Info("Starting to send log items...");
if (success)
while (!cancellationTokenSource.IsCancellationRequested)
{
// TODO: Fire event if instruction is sent via response!
}
else
{
logger.Error($"Failed to send ping: {ToString(response)}");
}
}
catch (Exception e)
{
logger.Error("Failed to send ping!", e);
}
try
{
if (logContent.TryDequeue(out var c) && c is ILogMessage message)
@ -293,9 +291,7 @@ namespace SafeExamBrowser.Server
["timestamp"] = message.DateTime.Ticks,
["text"] = message.Message
};
var content = json.ToString();
var contentType = "application/json;charset=UTF-8";
// TODO: Why can't we send multiple log messages in one request?
var success = TryExecute(HttpMethod.Post, api.LogEndpoint, out var response, content, contentType, authorization, token);
}
@ -304,6 +300,34 @@ namespace SafeExamBrowser.Server
{
logger.Error("Failed to send log!", e);
}
}
logger.Info("Stopped sending log items.");
}
private void Timer_Elapsed(object sender, ElapsedEventArgs args)
{
try
{
var authorization = ("Authorization", $"Bearer {oauth2Token}");
var content = $"timestamp={DateTime.Now.Ticks}&ping-number={++pingNumber}";
var contentType = "application/x-www-form-urlencoded";
var token = ("SEBConnectionToken", connectionToken);
var success = TryExecute(HttpMethod.Post, api.PingEndpoint, out var response, content, contentType, authorization, token);
if (success && TryParseInstruction(response.Content, out var instruction) && instruction == "SEB_QUIT")
{
Task.Run(() => TerminationRequested?.Invoke());
}
else
{
logger.Error($"Failed to send ping: {ToString(response)}");
}
}
catch (Exception e)
{
logger.Error("Failed to send ping!", e);
}
timer.Start();
}
@ -413,6 +437,24 @@ namespace SafeExamBrowser.Server
return exams.Any();
}
private bool TryParseInstruction(HttpContent content, out string instruction)
{
instruction = default(string);
try
{
var json = JsonConvert.DeserializeObject(Extract(content)) as JObject;
instruction = json["instruction"].Value<string>();
}
catch (Exception e)
{
logger.Error("Failed to parse instruction!", e);
}
return instruction != default(string);
}
private bool TryParseOauth2Token(HttpContent content)
{
try
@ -461,8 +503,12 @@ namespace SafeExamBrowser.Server
try
{
response = httpClient.SendAsync(request).GetAwaiter().GetResult();
if (request.RequestUri.AbsolutePath != api.LogEndpoint && request.RequestUri.AbsolutePath != api.PingEndpoint)
{
logger.Debug($"Completed request: {request.Method} '{request.RequestUri}' -> {ToString(response)}");
}
}
catch (TaskCanceledException)
{
logger.Debug($"Request {request.Method} '{request.RequestUri}' did not complete within {settings.RequestTimeout}ms!");