animethemes-server/app/Http/Middleware/Api/EnabledOnlyOnLocalhost.php

<?php

declare(strict_types=1);

namespace App\Http\Middleware\Api;

use App\Constants\FeatureConstants;
use Closure;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Config;
use Laravel\Pennant\Feature;

class EnabledOnlyOnLocalhost
{
    /**
     * @param  Closure(Request): mixed  $next
     */
    public function handle(Request $request, Closure $next): mixed
    {
        if (Feature::for(null)->active(FeatureConstants::ENABLED_ONLY_ON_LOCALHOST)) {
            abort_if(! in_array($request->ip(), Config::array('app.local_ips'), true), 403, 'Route only available for localhost');
        }

        return $next($request);
    }
}