Admin_DocumentController::getDataByIdAction PHP Method

    public function getDataByIdAction()
    {
        $document = Document::getById($this->getParam("id"));
        $document = clone $document;
        //Hook for modifying return value - e.g. for changing permissions based on object data
        //data need to wrapped into a container in order to pass parameter to event listeners by reference so that they can change the values
        $returnValueContainer = new \Pimcore\Model\Tool\Admin\EventDataContainer(object2array($document));
        \Pimcore::getEventManager()->trigger("admin.document.get.preSendData", $this, ["document" => $document, "returnValueContainer" => $returnValueContainer]);
        if ($document->isAllowed("view")) {
            $this->_helper->json($returnValueContainer->getData());
        }
        $this->_helper->json(["success" => false, "message" => "missing_permission"]);
    }