Rails 4 tutorial

Overview

This document provides step-by-step instructions describing how to build a Rails 4.0.2 app from scratch incorporating user authentication using Devise and user impersonation via the user_impersonate2 gem. Note that there is not (yet) a separate tutorial for adding Devise and user_impersonate2 to a Rails 3.2.x application, but the steps are more or less the same as those presented here.

Related materials:

• Sample app
• Step-by-step instructions for building sample app

0. Create the application

rails _4.0.2_ new sample-app

1. Generate home controller

rails generate controller home

2. Create index action for home controller

• Add app/views/home/index.html.erb
• Add route to config/routes.rb

3. Add Devise gem

• Add gem to Gemfile:

gem 'devise'

• Run Bundler to update the app:

bundle

• Generate Devise initializers etc.

rails generate devise:install

• Add settings to config/environments/development.rb:

  config.action_mailer.default_url_options = { :host => 'localhost:3000' }

• Add Devise links and flash to app/views/layouts/application.html.erb:

  <% if user_signed_in? %>
    <%= link_to "Edit profile (#{current_user.email})", edit_user_registration_path %>
    <%= link_to 'Sign out', destroy_user_session_path, :method => :delete %>
  <% end %>

  <p class="notice"><%= notice %></p>
  <p class="alert"><%= alert %></p>

• Generate Devise views

rails generate devise:views

• Generate User model

rails generate devise User

• Migrate the database

rake db:migrate

4. Create access-controlled Note model

• Generate Note model and scaffold:

 rails generate scaffold note user_id:integer text:string

5. Add authentication to all controllers

• Add filter to app/controllers/application_controller.rb:

  before_filter :authenticate_user!

6. Add belongs_to relationship to User

• In CreateNotes migration, change t.integer :user_id to t.belongs_to :user

• Add relationship to Note:

  belongs_to :user

• Add relationship to User:

  has_many :notes

• Migrate the database

rake db:migrate

7. Add user_impersonate2 gem

• Add gem to Gemfile:

gem 'user_impersonate2', :require => 'user_impersonate'

• Run Bundler to update the app:

bundle

• Generate initializer:

rails generate user_impersonate

8. Add impersonation header and link

• Modify app/views/layout/application.html.erb:

  <% if current_staff_user %>
    <%= render 'user_impersonate/header' %>
  <% end %>

• Modify app/views/home/index.html.erb:

  <% if current_user.staff? %>
    <li><%= link_to 'Impersonate', '/impersonate' %></li>
  <% end %>

9. Add staff concept to User model

• Add staff column to database:

rails generate migration add_staff_to_users staff:boolean
rake db:migrate

• Add to_s to User class:

  def to_s
    email
  end