ms-focus's Introduction

MS Focus Shop

This app sets up a shop with products, special offers and delivery charges. It provides a Ruby API and also a Rails JSON API.

Ruby API

The Basket class provides a simple public API to add or remove line items, and query the total charge.

basket = Basket.new

basket.add('J01') # Alternatively: Basket.add('J01')
basket.add('B01')
basket.remove('J01')
 
basket.total
  => 2990

basket.formatted_total
  => "£29.90"

basket.line_items
  => [ ... ]

Rails JSON API

You can do the same actions as above using a JSON API.

POST /api/basket/add.json { code: 'J01' }
POST /api/basket/add.json { code: 'B01' }
POST /api/basket/remove.json { code: 'J01' }

GET /api/basket.json
  => {
       total: 2990,
       formatted_total: '£29.90',
       items: [ ... ]
     }

Thoughts for Improvement

For the purpose of this exercise, the basket and its line items are global. In a real world scenario the LineItem class would be specific to a user or session.
If offers conflict or have conditions, the system would need to be more intelligent to decide which one to pick.
Perhaps there might be more criteria for offers, e.g. fixed discount, a range of products, get a free other product, etc.
Given plenty more time, of course a single-page front end could also be created for the app.
Basket can start to get large and might need extracting out some concerns, e.g. setup is not really a concern of the Basket, and the total calculations could be moved to a Checkout class.

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