Je pense avoir trouvé comment faire !
ArtabanMarketplace\Config\config.xml
....
<service id="ArtabanMarketplace.action.order_before_create" class="ArtabanMarketplace\Actions\OrderSeller">
<argument type="service" id="request"/>
<tag name="kernel.event_subscriber"/>
</service>
....
ArtabanMarketplace\Actions\OrderSeller.php
....
use Thelia\Core\HttpFoundation\Request;
....
/** @var Request $request */
protected $request = null;
public function __construct(Request $request) {
$this->request = $request;
}
....
protected function getSession() {
$session = $this->request->getSession();
return $session;
}
....