Coverflex Backend Exercise

Hello dear Backend developer!

Our team needs to build an app that can be used by company employees to self-manage their benefits. Our Frontend Engineer has already built a UI prototype to cover the required flows. We'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 us a simple React app for you to test out our 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.
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.

Good Luck! 🙌