Simple App 1 2020

We need to create a new Rails project, this time called simple_app:

$ cd ~/rails_projects
$ rails new simple_app --skip-test-unit
$ cd simple_app

The --skip-test-unit option to the rails command tells Rails not to generate a test directory associated with the default Test::Unit framework.

We need to update the Gemfile with the gems needed by our application. On the other hand, for our simple application we need two gems: the gem for RSpec and the gem for the RSpec library specific to Rails.

...
group :development, :test do
  gem 'rspec-rails', '2.14.1'
end

group :test do
  gem 'selenium-webdriver', '2.35.1'
  gem 'capybara', '2.1.0'
end

group :production do
  gem 'pg', '0.15.1'
  gem 'rails_12factor', '0.0.2'
end
...

The file includes rspec-rails in a development environment so that we have access to RSpec-specific generators, and it includes it in test mode in order to run the tests. We don’t have to install RSpec itself because it is a dependency of rspec-rails and will thus be installed automatically. We also include the Capybara gem, which allows us to simulate a user’s interaction with the sample application using a natural English-like syntax, together with Selenium, one of Capybara’s dependencies.

We also include the PostgreSQL and static assets gems in production for deployment.

To install and include the new gems, we run bundle update and bundle install:

$ bundle install --without production
$ bundle update
$ bundle install

We'll use a generate script to make controllers. Since we'll be making a controller to handle static pages, we'll call it the StaticPages controller. We'll also plan to make actions for a Home page, a Help page, and an About page. The generate script takes an optional list of actions, so we'll include two of the initial actions directly on the command line.

$ rails generate controller StaticPages home help --no-test-framework
      create  app/controllers/static_pages_controller.rb
       route  get 'static_pages/help'
       route  get 'static_pages/home'
      invoke  erb
      create    app/views/static_pages
      create    app/views/static_pages/home.html.erb
      create    app/views/static_pages/help.html.erb
      invoke  helper
      create    app/helpers/static_pages_helper.rb
      invoke  assets
      invoke    coffee
      create      app/assets/javascripts/static_pages.js.coffee
      invoke    scss
      create      app/assets/stylesheets/static_pages.css.scss

Since we generated home and help actions, the routes file already has a rule for each one:

config/routes.rb:

Rails.application.routes.draw do
  get 'static_pages/home'

  get 'static_pages/help'
...
end

The rule get "static_pages/home" maps requests for the URL /static_pages/home to the home action in the StaticPages controller. Also, by using get we arrange for the route to respond to a GET request. In other words, we generate a home action inside the StaticPages controller we automatically get a page at the address /static_pages/home:

app/controllers/static_pages_controller.rb

class StaticPagesController < ApplicationController

  def home
  end

  def help
  end
end

when visiting the URL /static_pages/home, Rails looks in the StaticPages controller and executes the code in the home action, and then renders the view corresponding to the action. In our case, the home action is empty, so all visiting /static_pages/home does is render the view (home.html.erb):

app/views/static_pages/home.html.erb

<h1>StaticPages#home</h1>
<p>Find me in app/views/static_pages/home.html.erb</p>

app/views/static_pages/help.html.erb

<h1>StaticPages#help</h1>
<p>Find me in app/views/static_pages/help.html.erb</p>