Secure Your SPA with Laravel Sanctum: A Step-by-Step Guide

In today's web development landscape, Single Page Applications (SPAs) are increasingly popular. But securing their interaction with backend APIs is crucial. Laravel Sanctum provides a lightweight and efficient solution for SPA authentication in Laravel applications. This guide will walk you through the steps of implementing SPA authentication using Laravel Sanctum.

Understanding Sanctum for SPAs

Unlike traditional token-based authentication, Sanctum leverages Laravel's built-in session management for SPAs running on the same domain as your Laravel backend. This offers several advantages:

1. CSRF Protection: Sanctum utilizes Laravel's CSRF (Cross-Site Request Forgery) protection mechanisms, safeguarding your application from malicious attacks.

2. Simplified Implementation: No complex token management is required. Sanctum relies on secure cookies for authentication.

Prerequisites:

1. A Laravel project

2. Basic understanding of Laravel controllers, routes, and middleware

Step 1: Installation

Sanctum comes bundled with Laravel by default. However, to activate it, run the following command:

Bash

php artisan sanctum:install

This command creates the necessary configuration files and migrates the database (if applicable).

Step 2: Configuration (Optional)

By default, Sanctum works well for most SPA setups. However, you can customize some settings in the config/sanctum.php file. These include:

1. State Management Driver: Choose the driver for storing CSRF tokens (e.g., cookie, database).

2. Domains: Specify the allowed domains for your SPA to access the Laravel API.

Step 3: Implement Login Functionality

Use Laravel's built-in authentication features (e.g., LoginController) to handle user login requests from your SPA. Upon successful login, Laravel will create a session and set the necessary cookies.

Step 4: Fetch CSRF Cookie in SPA

Before making any API requests from your SPA, you need to fetch the CSRF cookie from the Laravel backend. This can be done using a simple HTTP GET request to the /sanctum/csrf-cookie endpoint. Libraries like Axios or Fetch can handle this automatically.

Step 5: Secure API Endpoints with Middleware

Laravel's middleware allows you to control access to specific API routes. In this case, create a middleware that checks for the presence of a valid session or CSRF token before allowing the request to proceed.

Step 6: Sending Requests from SPA

With the CSRF cookie stored, your SPA can now make authenticated requests to your Laravel API endpoints. Include the CSRF token in the request header (usually as X-CSRF-TOKEN).

Additional Considerations:

1. Protecting Sensitive Data: While session-based authentication offers convenience, ensure you implement proper authorization checks within your controllers to restrict access to sensitive data based on user roles or permissions.

2. Token-Based Authentication for Different Domains: If your SPA and Laravel backend reside on different domains, consider using Sanctum's token-based authentication features documented in the official Laravel documentation https://laravel.com/docs/11.x/sanctum.

Conclusion

Laravel Sanctum provides a robust and user-friendly solution for securing SPA authentication in your Laravel applications. By following these steps and understanding the underlying concepts, you can effectively protect your API endpoints and enhance the overall security of your application.