Rails%203%20In%20Action

118 CHAPTER 6 Authentication and basic authorization
To round out the chapter, you’ll create another CRUD interface, this time for the
users resource, but with a twist.
Before you start, you must set up Devise!
6.1 What Devise does
Devise is an authentication gem that provides a lot of the common functionality for
user management, such as letting users sign in and sign up, in the form of a Rails
engine. An engine can be thought of as a miniature application that provides a small
subset of controllers, models, views, and additional functionality in one neat little
package. You can override the controllers, models, and views if you wish, though, by
placing identically named files inside your application. This works because Rails looks
for a file in your application first before diving into the gems and plugins of the application,
which can speed up the application’s execution time.
6.1.1 Installing Devise
To install Devise, first add the following line to the Gemfile, right after the end for the
:test group:
gem 'devise', '~> 1.4.3'
To install the Devise gem, run bundle. Once Devise is installed, you need to run the
generator, but how do you know the name of it? Simple! You can run the generate
command with no additional arguments to list all the generators:
rails generate
In this output, you’ll see devise:install listed. Hey, that’ll probably help you get
things installed! Let’s try it:
rails g devise:install
This code generates two files, config/initializers/devise.rb and config/locales/
devise.en.yml:
� config/initializers/devise.rb sets up Devise for your application and is the source
for all configuration settings for Devise.
� config/locales/devise.en.yml contains the English translations for Devise and is
loaded by the internationalization (I18n) part of Rails. You can learn about
internationalization in Rails by reading the official I18n guide: http://
guides.rubyonrails.org/i18n.html.
The code also gives you three setup tips to follow. The first setup tip tells you to set up
some Action Mailer settings, which you can place in your development environment’s
configuration at config/environments/development.rb and in your test environment’s
configuration at config/environments/test.rb:
config.action_mailer.default_url_options = { :host => 'localhost:3000' }