Praesentia

Praesentia is a simple Python-based web application to allow UGM students to fill their QR presence list without having another device in hand.

You can use an image file containing a QR code (can be obtained using a screenshot). Alternatively, you can just directly use the camera.

Frequently Asked Questions (FAQ)

Demo

The demo is available at https://lcat.dev/praesentia. Don't expect a 99.99% uptime, the server is an old Raspberry Pi 3. As a fallback, you can also use https://praesentia.herokuapp.com.

Background

• Many UGM students are required to use SIMASTER mobile app to scan QR codes to fill their presence list. This mostly means that a student needs at least two devices to make the mechanism works.
• Two devices are not always available.

API Source

I decompiled SIMASTER mobile app to get the source code. I also used interceptors to quickly recognize what was being sent and received.

Working Principle

It works just like scanning QR in the SIMASTER mobile app.

Side-effect

I don't think there is any except that you will get logged out of your SIMASTER app on your phone (just re-login, it will work again). I have never done research about the API's rate-limiting or any possible ban.

Installation and Deployment

Installation of Praesentia is fairly straightforward. You just need at least Python 3.6.

Installing Requirements

This app only requires flask (to serve the web) and requests library (to call the API). You can install both using pip.

pip install flask requests

Or, you can install it using the requirements.txt:

pip install -r requirements.txt

It is recommended but not necessary to separate an app's environment by using a virtual environment (e.g. venv).

Deployment

There are many ways to deploy Praesentia. You can use the following (but not limited to) ways:

• Gunicorn

gunicorn -b :6749 wsgi:app

• Flask development server

python wsgi.py

• Heroku: there is already a Procfile file, feel free to use and/or edit it.

Contribution

Contribution in any form will be highly appreciated.

License

This project is licensed under MIT License.