Laravel Sanctum Session Not Shared Across Subdomains in Nuxt App

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04-10-2024

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Keeping Your Nuxt.js App Authenticated: Solving the Sanctum Subdomain Session Sharing Problem

Problem:

Imagine this: you've set up a beautiful Nuxt.js frontend and a robust Laravel backend powered by Sanctum for user authentication. Everything works perfectly on your main domain, but when you try to access a subdomain, you're hit with a login prompt. You're logged in on the main domain, but the session isn't recognized on the subdomain! This is a common issue developers encounter when using Sanctum for authentication in a multi-domain setup.

Scenario:

Let's say you have a main domain, example.com, and a subdomain, blog.example.com. You're using Laravel Sanctum to manage user authentication and you've implemented Nuxt.js as your frontend framework. Your user successfully logs in on example.com, but when they navigate to blog.example.com, they are prompted to log in again.

Original Code:

Here's how your authentication setup might look in Laravel (using Sanctum):

// app/Models/User.php
public function tokens()
{
    return $this->hasMany(PersonalAccessToken::class);
}

// routes/api.php
Route::middleware('auth:sanctum')->group(function () {
    Route::get('/user', function (Request $request) {
        return $request->user();
    });
});

And in your Nuxt.js frontend (using Axios):

// nuxt.config.js
export default defineNuxtConfig({
  runtimeConfig: {
    public: {
      apiUrl: 'https://example.com/api'
    }
  }
})

// pages/blog/index.vue
<script setup>
import axios from 'axios'

const { data } = await axios.get(`${useRuntimeConfig().public.apiUrl}/user`)
console.log(data)
</script>

Insights and Solutions:

The core issue lies in how browsers handle cookies and the default Sanctum configuration. Sanctum creates and stores the authentication token in a cookie. By default, cookies are set with the SameSite attribute set to Lax, which means the browser won't send the cookie across different domains or subdomains.

Here's how to fix this:

1. Configure Sanctum Cookie:

   • SameSite Attribute: Update your Sanctum configuration in app/Http/Kernel.php to set the SameSite attribute to None:

     protected $middleware = [
         // ...
         \Laravel\Sanctum\Http\Middleware\EnsureFrontendRequestsAreStateful::class,
     ];
     
     protected $middlewareGroups = [
         'api' => [
             // ...
             'throttle:60,1',
             \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
             \Illuminate\Session\Middleware\StartSession::class,
             // ...
             \Laravel\Sanctum\Http\Middleware\EnsureFrontendRequestsAreStateful::class,
         ],
     ];
     

   • Secure Attribute: If your application uses HTTPS, set the secure attribute to true. This ensures the cookie is only sent over secure connections.

2. CORS Configuration:

   • Enable CORS: Ensure your Laravel application is configured to allow cross-origin requests from your Nuxt.js frontend. You can use a dedicated CORS middleware package like barryvdh/laravel-cors or manually configure it in your application's kernel.

3. Alternative Solutions:

   • API Tokens: Consider using API tokens for authentication instead of sessions. This provides a more stateless approach, eliminating session management issues.
   • Shared Cookie Domain: If possible, set a shared cookie domain (e.g., .example.com) for both your main domain and subdomains. This allows the browser to share the cookie across all domains.

Example (With CORS Configuration):

// app/Http/Kernel.php
protected $middlewareGroups = [
    'api' => [
        // ...
        \Barryvdh\Cors\HandleCors::class, // Assuming you're using the CORS package
        \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
        \Illuminate\Session\Middleware\StartSession::class,
        // ...
        \Laravel\Sanctum\Http\Middleware\EnsureFrontendRequestsAreStateful::class,
    ],
];

// config/cors.php
return [
    /*
    |--------------------------------------------------------------------------
    | Cross-Origin Resource Sharing (CORS) Configuration
    |--------------------------------------------------------------------------
    |
    | Here you may configure your settings for cross-origin resource sharing
    | or "CORS". This determines what resources may be accessed by clients
    | in the given origin.
    |
    | More information can be found on the Laravel documentation site:
    | https://laravel.com/docs/cors
    |
    */

    'paths' => ['api/*'],
    'allowed_methods' => ['GET', 'POST', 'PUT', 'DELETE'],
    'allowed_origins' => ['*'], // Be careful when setting this to '*'
    'allowed_origins_patterns' => [],
    'allowed_headers' => ['*'],
    'exposed_headers' => [],
    'max_age' => 0,
    'supports_credentials' => true, // Important for cookies
];

Important Note:

• Be cautious when using wildcard origins (e.g., *) in your CORS configuration. This could potentially expose your API to unauthorized access. It's generally recommended to restrict access to specific origins.

By implementing these solutions and carefully configuring your application, you can ensure that your Nuxt.js frontend can seamlessly access your Laravel backend, regardless of the domain or subdomain, maintaining a smooth authentication experience for your users.