1. ChaRLeS: An Open-Source Chat Room Learning System
Edoardo Bontà, Giovanni Torrisi, Marco Bernardo
Università di Urbino

2. Who’s ChaRLeS? ChaRLeS is a
virtual classroom that recreates an environment of a physical university classroom
multi-channel layered textual chat
LTI provider for Moodle and other learning management systems
real-time web application
open-source software

3. Why ChaRLeS? ChaRLeS is an acronym for Chat Room Learning System.
We developed it to overcome the weaknesses of other textual chat rooms (as the Moodle one) by taking care of:
functionality: multi-channel text chat features and filtered history log (see later)
efficiency: recent technologies, like HTML5 WebSockets, have been employed for sending/receiving messages with very low latency and reduced bandwidth consumption
usability: simple, intuitive, mobile-first, responsive, and user-friendly interfaces. No single-lined text area, no forced scroll every 3 seconds, no fragmented chat sessions / history logs
portability: any device (PC, smartphone, tablet) with an updated browser enabling JavaScript is enough at the client side. Major operating systems, i.e. Windows / Linux / MacOSX, can host the application at the server side
… but also reliability and maintainability, of course!

4. The underlying chat model
The underlying model of ChaRLeS addresses some common text chat room inefficiencies (Vronay, 1999) including:
Lack of intention indicators (difficulty to understand who a message is addressed to)
Low signal-to-noise ratio (didactic info mixed up with socialization or service messages)
Uselessness of chat history (lack of thread coherence, fragmentation, interruptions)
… and other functional issues
4-channel layered interaction system:
Lecture channel: used by the instructor, it can also be enabled for students [recorded]
Question channel: used by students, questions are submitted by the instructor [recorded]
Service channel: used by all for greetings and organizational messages
Private channel: used by all for sending private messages to selected users
A similar model has been successfully applied to the chat room of Land of Learning (LoL), an old proprietary LMS using Java applets for asynchronous messaging [Mec Informatica ( Roma, & University of Urbino (

5. Architecture of the web application ChaRLeS
Hosting support (server)
Self-hosting: ASP.NET Core for Windows, Linux, MacOSX
Client application
Service
Real-time web application
written in pure HTML + JavaScript
Other useful JS libs
JQuery, Bootstrap
Real-time JS library
SignalR.js
Real-time support
SignalR
Web service support
web API
Custom services
written in C#
Reverse
Proxy
(Nginx)
HTTP
Application path
HTTP + WebSocket
Service paths
Unified path
apps/services>
HTTPS + WebSocket
relative references
Other apps/services

6. The chat room instance page of ChaRLeS

7. … and the points of view of Steve and Leo

8. The chat room session log
The history log of the chat room session is as follows:
Programming Languages - A.A. 2015/ CFU
Last session start time: 01/09/ :15:00 [server local time]
<Question from Steve Smith>
What does OOP mean?
<John Doe>
It stands for "Object-Oriented Programming"
Two terms that I often hear are "business logic" and "presentation logic"
Business logic is the domain logic, that's the part of a program encoding the real-world business rules.

9. Configuration of the Moodle plugin mod_charles

10. Conclusion and future work
The outcome of the chat model and of the design/implementation of the architecture is ChaRLeS, an easy-to-use textual chat room, that can be interfaced with Moodle or other LMSs through the LTI protocol.
Common textual chat inefficiencies have been addressed thanks to the multi-channel layered interaction model.
Performance and other technical issues have been addressed by developing the web application with the help of new technologies, as HTML5 WebSockets and real-time libraries (SignalR).
Future work
LaTeX equation editor based on JS library MathJax;
Virtual whiteboard relying on SVG (Scalable Vectorial Graphics) image format;
Instant poll for receiving immediate feedbacks from participants.