How do I check the current user session?

Question

In Drupal 7, I was able to use bootstrap.inc in an external PHP script, which was a custom set of pages that simply bootstrapped Drupal to check the user was logged in Drupal.

The following code is a very basic version that just returns the username of an active session.

require_once '../includes/bootstrap.inc';
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);
global $user;
echo $user->name;

I'm looking to implement something similar in Drupal 8. The same script returns a server error.

Error: Class 'Drupal\Core\Session\AccountInterface' not found in core/includes/bootstrap.inc, line 63

How should I check for an active user session from an external script, in Drupal 8?

Answer 1

You can't really do something like that in Drupal 8.

The short story is that we use Symphony for the Request / Response flow, so actually bootsrapping Drupal is a lot more complex than simply requiring the bootstrap.inc file. If you look at the index.php file, you can see an overview of a request in Drupal 8:

use Drupal\Core\DrupalKernel;
use Symfony\Component\HttpFoundation\Request;

$autoloader = require_once 'autoload.php';

$kernel = new DrupalKernel('prod', $autoloader);

$request = Request::createFromGlobals();
$response = $kernel->handle($request);
$response->send();

$kernel->terminate($request, $response);

Most of this happens in the DrupalKernal::handle call. You could probably make a custom script that hooks into Drupal, but it probably will be a lot easier and more maintable to actually have this code be part of your Drupal installation.