Virtual Programming Laboratory - ILIAS plugin

The virtual programming lab (ViPLab) is a browser-based programming environment. This plugin integrates the question type ViPLab in ILIAS and allows for providing programming tasks in context of test and assessment.

The plugin is a part of the ViPLab infrastructure mostly hosted and provided by the University of Stuttgart. In order to gain access to the required message middleware and further ViPLab backends, please contact the ILIAS support. This page provides quick setup instructions and a compact overview of the plugin settings to be configured by ILIAS administrators.

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Components

• VipLab ILIAS plugin
  • Javascript (GWT) based frontend for teachers and students
  • ILIAS integration for test and assessment
  • Import and export with respect to the QTI specification
• VipLab Backend¹
  • Scalable program code compilation and evaluation
  • Supported languages: C, C++, DuMuX, Java, Matlab and Octave
• E-learning Community Server (ECS)¹
  • Message-based communication between ViPLab components within and across communities
  • Message queuing
• VipEval¹ (optional service)
  • Evaluation and scoring service for automatically evaluable programming tasks

¹ provided as a service by the University of Stuttgart

Preparation and Install

General requirements and dependencies

• ILIAS (min. version 9.0.0)
• VipLabCron (ILIAS plugin)
• VipLabEvent (ILIAS plugin)

Required access rights

• Root access to the ILIAS installation on the webserver
• Admin rights within the ILIAS system

Webserver preparation

Important: The ViPLab frontend sends requests to URLs (ECS server) that do not match with the origin. To avoid conflicts with the CORS policies, a ProxyPass must be specified on the web server which hosts ILIAS or on the load balancer (e.g., nginx) which routes requests to the ILIAS web server. The local path /_ecs_ must be mapped to https://vip.uni-stuttgart.de for request as well as for response headers.

The following example shows a ProxyPass specified within an Apache configuration.

<VirtualHost *:443>
  ServerName ilias.example-university.edu
  DocumentRoot "/var/www/ilias"
 
  # ...
 
  # ProxyPass rules
  SSLProxyEngine On
  ProxyRequests Off
  ProxyPreserveHost Off
  ProxyPass /_ecs_ https://vip.uni-stuttgart.de
  ProxyPassReverse /_ecs_ https://vip.uni-stuttgart.de
</VirtualHost>

Note that the apache modules ssl, proxy and proxy_http must also be enabled:

a2enmod ssl proxy proxy_http
systemctl restart apache.service

Install

1. Access the installation directory of your running ILIAS instance (e.g., /var/www/ilias) and clone the VipLab plugin with its dependencies:

   cd /var/www/ilias
   git clone https://github.com/TIK-NFL/ViPLab.git ./Customizing/global/plugins/Modules/TestQuestionPool/Questions/assViPLab
   git clone https://github.com/TIK-NFL/ViPLabCron.git ./Customizing/global/plugins/Services/Cron/CronHook/ViPLabCron
   git clone https://github.com/TIK-NFL/ViPLabEvent.git ./Customizing/global/plugins/Services/EventHandling/EventHook/ViPLabEvent
   

2. Access ILIAS by a web browser and go to: Administration → Extending ILIAS → Plugins.
3. Install the ViPLabCron, ViPLabEvent and the assViPLab plugins respectively (Actions → Install).
4. Activate the ViPLabCron, ViPLabEvent and the assViPLab plugins respectively (Actions → Activate).

Configuration

ECS

1. Access ILIAS by a web browser and and create a new category 'ViPLab' for course links. Note the category id which can be read from the URL parameter ref_id.
2. Go to Administration → Extending ILIAS → ECS → Add New ECS.
3. Configure as follows:

Property	Value
Enable ECS Functionality	[X]
Name of ECS Configuration	VIPLab ECS
Server URL	ilias.example-university.edu/_ecs_
Protocol	HTTPS
Port	443
Authentication Type	(o) Username/Password (provided by U Stuttgart)
Import ID	ref_id of the course created before
Role Assignment	Guest
Activation Period Extension	6

ViPLab Plugin

1. Access ILIAS and go to Administration → Extending ILIAS → Plugins.
2. On the assViPLab entry, click: Actions → Configure.
3. Select the ECS server to be used by VipLab and save.
4. Optionally, select the Membership ID (MID) of the server for automated corrections (Evaluation Backend) and receipt (Receiver for Scoring Results).
5. Map each supported language to the server (MID) the calculation tasks will be processed on.
   • Productive systems are more stable compared to test systems.
   • Test systems offer more features, such as newer compiler flags.
6. Save again.

Integration (optional)

1. Activate the ViPLabCron in Administration → System Settings and Maintenance → Cron Jobs.
2. Activate manual scoring of ViPLab questions in Administration → Repository and Objects → Test and Assessment.