Coverflex Backend Exercise

Hello dear Backend developer!

Your Project Manager needs you to quickly build an app that can be used by company employees to self-manage their benefits. Our Frontend Developer has already built a UI prototype to cover the required flows. You'll need to build an API to provide backend functionality to this prototype and integrate both.

The API should include these use cases:

• Retrieve data from a single user
  • users are indexed and queried by username
• Retrieve a collection of products
  • products must have a unique identifier, a price and a name
• Placing an order
  • users aren't allowed to place an order if their current balance isn't enough for the order total
  • users aren't allowed to order a product previously ordered
  • orders must record which user is ordering, which products are being ordered and what the total amount is

Our Frontend Developer is expecting these API endpoints:

• GET /api/users/:user_id
  • returns a single user
  • if user_id doesn't exist, it creates a new user
  • output {"user": {"user_id": "johndoe", "data": {"balance": 500, "product_ids": [...]}}}
• GET /api/products
  • returns a list of all products
  • output {"products": [{id: "netflix", "name": "Netflix", price: 75.99}, ...] }
• POST /api/orders
  • creates a new order
  • input {"order": {"items": ["product-1", "product-2"], "user_id": "johndoe"}}
  • output 200 {"order": {"order_id": "123", "data": {"items": [...], "total": 500}}}
  • output 400 {"error": "products_not_found"}
  • output 400 {"error": "products_already_purchased"}
  • output 400 {"error": "insufficient_balance"}

Notes:

• You're free to use whatever means and technology to achieve the goal

Web App

Our Frontend Developer has kindly provided you a simple React app for you to test out your service.

Let me guide you through how to set it up:

1. Go ahead and clone this repo.
2. Go inside frontend folder : cd frontend/
3. Make sure you have Node installed.
   • If using wsl2, set this environment variable. Is this necessary because Node tries to open a browser: export BROWSER=none
4. Install npm dependencies: npm install
5. Run it in development mode: npm start

Now you should see something at http://localhost:3000

Additional Requirements:

In development mode, this react app is expecting the local backend service to expose port 4000.

Setup

For this challenge, please fork this repository, and create your solution inside of it, located inside backend folder. As soon as you are finished, go ahead and make a Pull Request back to this repository.

Good Luck! 🙌