Remember me functionality in Ruby on Rails - Mini Project: Build & Apply

Remember Me Functionality

📖 Scenario: You are building a simple login system for a website. Users can choose to stay logged in even after closing their browser by selecting a "Remember me" checkbox.This feature uses cookies to keep users logged in automatically on their next visit.

🎯 Goal: Create a basic "Remember me" feature in a Rails app that sets a persistent cookie when the user logs in and uses it to authenticate the user automatically on future visits.

📋 What You'll Learn

Create a method to generate a remember token and save its digest in the user model

Add a controller variable to hold the remember token

Implement the logic to set and delete the remember cookie

Add the final helper methods to check and forget the user session

💡 Why This Matters

🌍 Real World

Remember me functionality is common on websites to improve user experience by keeping users logged in between visits without re-entering credentials.

💼 Career

Understanding how to implement secure persistent login is important for web developers working on authentication systems and user session management.

1

Add remember token and digest to User model

In the User model, add a method called remember that generates a new token using SecureRandom.urlsafe_base64 and saves its digest using BCrypt::Password.create in an attribute called remember_digest.

Ruby on Rails

class User < ApplicationRecord
  # Add remember method here
  # Your code here
end

Need a hint?

Use attr_accessor :remember_token to create a temporary token attribute.

Use SecureRandom.urlsafe_base64 to generate the token.

2

Add remember token variable in Sessions controller

In the SessionsController, create an instance variable @remember_token and assign it a new token generated by SecureRandom.urlsafe_base64.

Ruby on Rails

class SessionsController < ApplicationController
  # Create @remember_token variable here
  # Your code here
end

Need a hint?

Assign @remember_token inside the create action.

3

Set and delete remember cookies in Sessions helper

In the SessionsHelper module, write two methods: remember(user) that sets a permanent signed cookie :user_id and a permanent cookie :remember_token with the user's remember token, and forget(user) that deletes these cookies.

Ruby on Rails

module SessionsHelper
  # Define remember(user) method here
  # Define forget(user) method here
  # Your code here
end

Need a hint?

Use cookies.permanent.signed for secure user ID storage.

Use cookies.permanent for the token.

4

Add helper methods to check and forget user session

In the SessionsHelper, add a method current_user that returns the logged-in user by checking the signed :user_id cookie and authenticating the :remember_token. Also add a method logged_in? that returns true if current_user is not nil.

Ruby on Rails

module SessionsHelper
  # Define current_user method here
  # Define logged_in? method here
  # Your code here
end

Need a hint?

Use cookies.signed[:user_id] to get the user ID.

Use BCrypt::Password.new(...).is_password?(...) to verify the token.