Ruby on Rails - Using Devise for Authentication

Introduction

Devise is a flexible and comprehensive authentication solution for Rails based on Warden. It handles user registration, session management, password recovery, and more. This guide will walk you through implementing authentication in your Rails application using Devise.

Installing Devise

First, add Devise to your Gemfile and install it:

# Add Devise to your Gemfile
gem 'devise'

# Install the gem
bundle install

# Run the Devise generator
rails generate devise:install
                

The generator sets up the necessary configuration files and instructions for further setup.

Configuring Devise

Follow the instructions provided by the generator to configure Devise. Here are the typical steps:

• Ensure you have a default URL option configured in your config/environments/development.rb file:

# config/environments/development.rb
config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }
                

• Add flash messages for Devise in your application layout:

# app/views/layouts/application.html.erb
<%= notice %>
<%= alert %>
                

Generating the User Model

Generate a User model with Devise:

# Generate the User model with Devise
rails generate devise User

# Run the migrations
rails db:migrate
                

This command creates a User model with the necessary database columns and Devise modules for authentication.

Setting Up Routes

Devise provides a set of helper methods to handle routing. Add the following to your config/routes.rb file:

# config/routes.rb
Rails.application.routes.draw do
  devise_for :users
  root to: 'home#index'
end
                

This sets up routes for user registration, login, logout, and other authentication actions.

Customizing Devise Views

To customize the views provided by Devise, run the following generator:

# Generate Devise views for customization
rails generate devise:views
                

This copies the Devise views to your application, allowing you to customize them as needed.

Adding Additional Fields to User Model

To add additional fields to the User model, create a migration:

# Generate a migration to add fields
rails generate migration AddFieldsToUsers first_name:string last_name:string

# Run the migration
rails db:migrate
                

Update the app/controllers/application_controller.rb to permit the additional parameters:

# app/controllers/application_controller.rb
class ApplicationController < ActionController::Base
  before_action :configure_permitted_parameters, if: :devise_controller?

  protected

  def configure_permitted_parameters
    devise_parameter_sanitizer.permit(:sign_up, keys: [:first_name, :last_name])
    devise_parameter_sanitizer.permit(:account_update, keys: [:first_name, :last_name])
  end
end
                

Setting Up Mailer

Devise uses ActionMailer to send emails for password recovery and other features. Configure the mailer settings in config/environments/development.rb:

# config/environments/development.rb
config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
  address: 'smtp.example.com',
  port: 587,
  user_name: 'your_email@example.com',
  password: 'your_password',
  authentication: 'plain',
  enable_starttls_auto: true
}
                

Testing Devise Setup

Start the Rails server and navigate to the registration and login pages to test the Devise setup:

# Start the Rails server
rails server

# Navigate to the following URLs
# http://localhost:3000/users/sign_up
# http://localhost:3000/users/sign_in
                

Ensure that you can register a new user, log in, log out, and recover passwords.

Conclusion

Devise provides a comprehensive and flexible solution for authentication in Rails applications. This guide covered the steps to install and configure Devise, generate the User model, set up routes, customize views, add additional fields, configure the mailer, and test the setup. By following these steps, you can implement robust authentication in your Rails application using Devise.