1. Introduction

Goal

In this tutorial, we will learn how to manage sessions and cookies securely in a Rails application. With the correct management of sessions and cookies, you can maintain user login status and personalize user experience effectively.

Learning Outcomes

By the end of this tutorial, you will be able to:
- Understand the role of sessions and cookies in a Rails application
- Manage sessions and cookies securely
- Implement session and cookie management in your Rails application

Prerequisites

Before you start, ensure you have:
- Basic understanding of Ruby on Rails
- Rails installed on your computer
- A text editor, such as Atom or Sublime Text
- Basic understanding of HTTP requests and responses

2. Step-by-Step Guide

Understanding Sessions and Cookies

Sessions and cookies are used to maintain state in stateless HTTP protocols. A session is stored on the server, while a cookie is stored on the user's browser. Cookies are used to identify a session.

Managing Sessions

In Rails, you can use the session method to set or get session data. For example, session[:user_id] = @user.id sets a session.

Managing Cookies

Use the cookies method to set, get or delete cookies. For example, cookies[:user_id] = @user.id sets a cookie.

Security

Set secure: true to ensure cookies are only sent over HTTPS. Use http_only: true to prevent JavaScript from accessing cookies.

3. Code Examples

Example 1: Setting a Session

# Log in a user
def create
  @user = User.find_by(email: params[:email])

  if @user && @user.authenticate(params[:password])
    # Set user id in session
    session[:user_id] = @user.id

    redirect_to root_path
  else
    render :new
  end
end

Example 2: Setting a Secure Cookie

# Set a secure, http_only cookie
cookies.signed[:user_id] = { value: @user.id, expires: 1.year.from_now, secure: true, http_only: true }

4. Summary

In this tutorial, we've learned about managing sessions and cookies in Rails. We've seen how to set sessions and cookies, and how to make them secure.

To learn more, you can check out these resources:
- Rails Sessions
- Rails Cookies
- Rails Security Guide

5. Practice Exercises

1. Exercise 1: Create a Rails application and implement user login using sessions.
2. Exercise 2: Modify the application to use secure cookies instead.
3. Exercise 3: Add a "Remember me" checkbox to the login form. If checked, set a persistent cookie.

Solutions:
1. Solution 1: Use the session method to set the user id after successful authentication.
2. Solution 2: Use the cookies.signed method to set a secure, http_only cookie with the user id.
3. Solution 3: Add a checkbox to the form, and use the cookies.permanent.signed method to set a persistent cookie if the checkbox is checked.