How can I configure Axios to work with Laravel's CORS settings

Understanding CORS and Why Configuration Matters

Browsers restrict cross-origin HTTP requests initiated from scripts to prevent vulnerabilities like cross-site request forgery. CORS policy is a mechanism that uses HTTP headers to tell browsers if an application running at one origin (domain) is permitted to access selected resources from a server at a different origin. For Laravel APIs accessed from a different frontend domain or port, configuring CORS properly on Laravel is essential.

Step 1: Install Laravel CORS Support

Starting with Laravel 7, CORS support is included natively via the package `fruitcake/laravel-cors`. For Laravel 7 and newer (including latest versions), this package comes pre-installed but may require enabling/configuration.

- If using older Laravel ( ['api/*', 'sanctum/csrf-cookie'],

'allowed_methods' => ['*'],

'allowed_origins' => ['*'], // In production, restrict this to your frontend domain e.g. ['https://example.com']

'allowed_origins_patterns' => [],

'allowed_headers' => ['*'],

'exposed_headers' => [],

'max_age' => 0,

'supports_credentials' => false, // Set true if you use cookies or authentication headers like csrf

];

- `paths`: Specifies API routes to enable CORS on (commonly `api/*`).
- `allowed_origins`: Use the frontend app's URL(s). `'*'` allows all but is discouraged for production.
- `allowed_methods`: HTTP methods allowed from the frontend.
- `allowed_headers`: Headers accepted in requests.
- `supports_credentials`: Set to `true` if your frontend sends cookies or HTTP auth info, else false.

Always clear config cache after changes:

### Step 3: Register Middleware

Laravel automatically registers CORS middleware with the package in `app/Http/Kernel.php`. Look for:

If it's not there, add it to global middleware or route middleware depending on your needs.

### Step 4: Frontend Axios Configuration

Axios requests need to be set up correctly to align with Laravel's CORS settings:

- Specify the full API base URL with protocol and port if applicable.

- If your Laravel API requires cookies or credentials (e.g., sessions), set `withCredentials` to `true` in Axios config.

Example Axios setup for a React or Vue frontend:

const apiClient = axios.create({
baseURL: 'http://your-laravel-api-domain.com/api',
headers: {
'Content-Type': 'application/json',
},
withCredentials: false, // Set true if backend expects cookies/auth
});

export default apiClient;

For requests requiring credentials:

### Step 5: Handling CSRF Tokens

Laravel's default frontend scaffolding includes CSRF token handling in Axios, which automatically sends the CSRF token in request headers to protect the backend.

- Ensure the CSRF cookie middleware and route (`sanctum/csrf-cookie` or `csrf-cookie` on older versions) are included in the API or web routes.

- Axios default headers often include `X-CSRF-TOKEN` and `X-Requested-With`.

If using Sanctum for SPA authentication, this is crucial.

### Step 6: Common Issues and Solutions

- Wildcards and Credentials Conflict: If `supports_credentials` is true, you cannot use `allowed_origins` as `'*'`. Set explicit origins.

- Clearing Cache: After any config change, run `php artisan config:cache` and/or clear route cache.

- Preflight Requests: CORS preflight OPTIONS requests need to be handled by Laravel automatically through the middleware. Ensure OPTIONS requests are not blocked.

- Proxy Setup: In some setups, especially development, proxying frontend requests through the Laravel server or using frontend development server proxy settings can simplify CORS issues.

### More Advanced Settings

- Use `allowed_origins_patterns` to specify allowed origins using regex patterns if origins are dynamic.

- Adjust `max_age` to cache preflight response headers and reduce OPTIONS requests.

- Use `exposed_headers` if frontend needs access to non-simple response headers.

### Testing and Debugging CORS

- Use browser developer tools to view request and response headers.

- Validate that `Access-Control-Allow-Origin` matches the front-end origin.

- Verify HTTP response status code for OPTIONS preflight requests.

- Temporarily set `allowed_origins` to `'*'` to determine if CORS is the problem.

- Use tools like Postman for backend response inspection (Postman doesn't enforce CORS, so headers must be correct anyway).

### Summary of Integration Flow

1. Install and configure Laravel CORS middleware.
2. Ensure your `cors.php` settings allow your frontend domain, methods, and headers on API paths.
3. Clear Laravel config cache.
4. Set Axios base URL and `withCredentials` as per your session/auth needs.
5. Ensure CSRF tokens are managed if applicable.
6. Debug with browser console and verify HTTP headers.
7. Adjust and refine configuration for security and production-level restrictions.

By properly setting up Laravel's CORS middleware with explicit origins, allowed methods, and headers, and aligning Axios request settings (like `withCredentials`), you will enable your frontend apps to seamlessly communicate with Laravel APIs without CORS issues.

### Example Final Configuration (Laravel cors.php)

'allowed_methods' => ['GET', 'POST', 'PUT', 'DELETE', 'OPTIONS'],

'allowed_origins' => ['http://localhost:3000'], // Your frontend URL

'allowed_origins_patterns' => [],

'allowed_headers' => ['Content-Type', 'X-Requested-With', 'Authorization', 'X-CSRF-TOKEN'],

'exposed_headers' => [],

'max_age' => 0,

'supports_credentials' => true,
];

### Example Axios Configuration with Credentials

const apiClient = axios.create({
baseURL: 'http://localhost:8000/api',
withCredentials: true, // Important if the API requires cookies/auth
headers: {
'Content-Type': 'application/json',
'X-Requested-With': 'XMLHttpRequest',
},
});

export default apiClient;
```

This ensures that Axios sends necessary headers and shares credentials as required by Laravel's CORS security settings.