chapter_14.md

Chapter 14 - Exposing the Books Resource

We are going to start exposing stuff to the outside world, namely the books resource. To do so, we need to create the book controller and its first action, index.

Creating the Controller

Create the file that will hold the books controller in app/controllers/.

touch app/controllers/books_controller.rb

Before adding anything to the controller create the following folders:

mkdir spec/requests && touch spec/requests/books_controller_spec.rb

The minimum content for this test file is to have a describe "GET /api/books" block where we can check that the GET method is working properly. In the background, Rails will route this resource to the books controller and the index action. The route will be the link between the resource and the controller.

The Index Action

The first test we need is to make sure that GET /api/books returns 200 OK.

Returning Books

We are going to define a few lets to avoid repetition in the tests. The let is just an elegant way of defining variables in your tests. To give you an idea, defining the following let

let(:my_variable) { "my variable" }

is the equivalent of something like this:

def my_variable
  @my_variable ||= "my variable"
end

All let definitions are wiped between each test!

1. RSpec fundamentals: setup, naming and basic structure

2. RSpec fundamentals: a basic glossary

Seeding Some Data

If we run rails server and head to http://localhost:3000/api/books, we get something that looks like this:

{
  "data": []
}

We need to add seed data to db/seeds.rb. After that has been completed, run rails db:seed to populate the database.

Adding a RSpec Helper

In all our request, we will be checking the json_body variable. Creating a small RSpec helper will save us from putting let(:json_body) { JSON.parse(response.body) } everywhere.

mkdir spec/support && touch spec/support/helpers.rb