My solution uses a back-end application, a front-end webpage, two data files for products and discounts and a file database for the baskets.

I have used a CSV file for the products and another for the discounts. It is the most simple and versatile way that I thought to manage the stock and discounts without an external database, and can be edited while the server is running.

To store the baskets I have used a Python shelve, to store them in a file with the structure of a dictionary (similar to json), in order to not lose the basket at refresh the page, change the browser or at stop the server.

For the back-end, I have created a REST API writen in Python3 using Flask, because Python comes with most UNIX operating systems, and with a couple of libraries you can have a simple REST API.

For the front-end, I have used a simple HTML and raw JS, to do not use a large amount of libraries and complicate things.

The project requires a simple setup, install the Flask libraries:

pip3 install -r requirements.txt

and execute it

python3 run.py

A simple description of each file:

• run.py: Flask setup
• controllers.py: Endpoints and operations
• models.py: Product and Discount classes
• index.html: Webpage
• behavior.js: JS scripts
• styles.css: CSS styles
• products.csv & discounts.csv: Data files