A quick solution for Guzzle 7 to get the request URL from the response.
Install via composer
composer require dezento/effective-url-middleware
require "vendor/autoload.php";
use Dezento\EffectiveUrlMiddleware;
use GuzzleHttp\HandlerStack;
use GuzzleHttp\Client;
$stack = HandlerStack::create();
$stack->push(EffectiveUrlMiddleware::middleware());
$client = new Client([
'handler' => $stack
]);
$response = $client->request('GET', 'http://httpbin.org/get');
echo $response->getHeaderLine('X-GUZZLE-EFFECTIVE-URL');