Devise gem overview in Ruby on Rails - Mini Project: Build & Apply

Devise Gem Overview in Rails

📖 Scenario: You are building a simple Rails application that needs user authentication. To make this easier, you will use the Devise gem, which helps add sign up, login, and logout features quickly.

🎯 Goal: Learn how to set up the Devise gem step-by-step in a Rails app. You will create the initial user model, configure Devise, add authentication routes, and complete the setup to have a working user login system.

📋 What You'll Learn

Create a new Rails app with Devise installed

Generate a User model with Devise modules

Configure Devise settings in the app

Add Devise routes to the application

Complete the setup to enable user authentication

💡 Why This Matters

🌍 Real World

Most web apps need user accounts and login features. Devise makes adding these features fast and secure.

💼 Career

Knowing how to use Devise is a key skill for Rails developers working on real-world applications with user authentication.

1

Install Devise and Generate User Model

Add the devise gem to your Gemfile and run bundle install. Then run rails generate devise:install to set up Devise. Finally, generate a User model with Devise by running rails generate devise User.

Ruby on Rails

# Add gem 'devise' to Gemfile and run bundle install
# Then run rails generate devise:install
# Then run rails generate devise User

Need a hint?

Start by adding gem 'devise' to your Gemfile. Then run the commands to install and generate the User model.

2

Configure Devise Settings

Open the config/initializers/devise.rb file and set the config.mailer_sender to "[e-mail]". Also, ensure you have run rails db:migrate to create the users table.

Ruby on Rails

gem 'devise'

# Set config.mailer_sender in config/initializers/devise.rb
# Run rails db:migrate to create users table

Need a hint?

Devise needs a mailer sender email set. Also, run migrations to create the users table.

3

Add Devise Routes to Your Application

In the config/routes.rb file, add devise_for :users to create all the routes needed for user authentication.

Ruby on Rails

gem 'devise'

# Add devise_for :users in config/routes.rb
# Your code here

Need a hint?

This line adds all the routes Devise needs for user sign up, login, logout, and more.

4

Complete Setup and Test Authentication

Add a root route in config/routes.rb pointing to home#index. Create a simple HomeController with an index action and view. Use before_action :authenticate_user! in the controller to require login. This completes the Devise setup for user authentication.

Ruby on Rails

gem 'devise'

# Add root route and HomeController with authenticate_user! before_action
# Your code here

Need a hint?

Set a root page and protect it so only logged-in users can see it.