Allow specific domains and url's | Access-Control-Allow-Origin in PHP

cors-headers.php

$origin = $_SERVER['HTTP_ORIGIN'];
$allowed_domains = [
    'http://localhost',
    'http://localhost:8080',
    'http://localhost:8081',
    'https://example.com',
    'https://test.example.com',
    'http://example.net',
];

if (in_array($origin, $allowed_domains)) {
    header('Access-Control-Allow-Origin: ' . $origin);
}