🔗 Follows a redirect chain path and either redirects to the final URL or returns it

fn.flatten_redirect_chain.php

/**
 * fn.flatten_redirect_chain.php
 * Follows a redirect chain path and either redirects to the final URL or returns it
 * Author: Matheus Pratta <github.com/matheusmk3>
 * License: 0BSD
 * Version: 1.0.0
 * 
 * @param string $destination The URL that is part of a redirect chain and shall be resolved
 * @param mixed $redirect The redirect type to be used (301/302) or false for returning the final URL as string
 * 
 * @return string The final URL of the chain, only present when $redirect is false
 */
if (!function_exists('flatten_redirect_chain')) {
  function flatten_redirect_chain ($destination, $redirect = 302) {
    // Uses cURL to follow all redirects chain
    $curl = curl_init($destination);
    curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
    curl_setopt($curl, CURLOPT_CUSTOMREQUEST, 'HEAD');
    curl_setopt($curl, CURLOPT_NOBODY, true);
    curl_exec($curl);

    // Extracts the final URL
    $url = curl_getinfo($curl, CURLINFO_EFFECTIVE_URL);

    // If we are NOT redirecting, return the URL
    if (false === $redirect) return $url;

    // In other cases, does the HTTP redirect
    http_response_code($redirect);
    header('Location: ' . $url);
    exit;
  }
}