Drupal Force HTTPS Redirect with PHP

settings.https_redirect.php

<?php

/**
 * @file
 * Always redirect to HTTPS.
 */

if (
  php_sapi_name() !== 'cli' &&
  strtoupper($_SERVER['HTTPS'] ?? '') !== 'ON' &&
  ($_SERVER['HTTP_X_FORWARDED_PROTO'] ?? NULL) !== 'https'
) {
  header('HTTP/1.0 301 Moved Permanently');
  header("Location: https://{$_SERVER['HTTP_HOST']}{$_SERVER['REQUEST_URI']}");
  exit;
}