Create own action to clone/duplicate TYPO3 8.7 extbase object with nested child elements

Question

I build my extbased TYPO3 extension in TYPO3 8.7 . It is a Backend-Module. In the controller, i write my own action to clone the object. In this example, i want to clone/duplicate the object 'Campaign' and safe it with a modified title, like add the 'copy' text to the title. But the new object should have also its own new child elements that must be exact copies. When the action is called, i get only a copy of the Object, but no childs. Is there an example or best case how to handle this task? I did not find, even i found some questions and answers that are on the same topic, but older version. i hope that upd to date, there is a more straight forward solution. Thank you for every hint that points me to the right ideas and maybe an up to date and version example. Here is what i have i my controller. How do i implement recursiv copying of all child elements (and some childs have childs, too)?

    /**
     * action clone
     * @param \ABC\Copytest\Domain\Model\Campaign $campaign
     * @return void
     * @var \ABC\Copytest\Domain\Model\Campaign $newCampaign
     */

    public function cloneAction(\ABC\Copytest\Domain\Model\Campaign $campaign) {
        $newCampaign = $this->objectManager->get("ABC\Copytest\Domain\Model\Campaign");
        $properties = $campaign->_getProperties();
        unset($properties['uid']);
        foreach ($properties as $key => $value) {
            $newCampaign->_setProperty($key, $value);
        }
        $newCampaign->_setProperty('title', $properties['title']. ' COPY');
        $this->campaignRepository->add($newCampaign);
        $this->addFlashMessage('Clone was created', '', \TYPO3\CMS\Core\Messaging\AbstractMessage::OK);
        $this->redirect('list');
    }

Answer 1

I am aware that this question has been answered a long time ago. But I want to provide my solution to create a deep copy for further reference. Tested on TYPO3 9.5.8.

private function deepcopy($object)
{
    $clone = $this->objectManager->get(get_class($object));
    $properties = \TYPO3\CMS\Extbase\Reflection\ObjectAccess::getGettableProperties($object);
    foreach ($properties as $propertyName => $propertyValue) {
        if ($propertyValue instanceof \TYPO3\CMS\Extbase\Persistence\ObjectStorage) {
            $v = $this->objectManager->get(\TYPO3\CMS\Extbase\Persistence\ObjectStorage::class);
            foreach($propertyValue as $subObject) {
                $subClone = $this->deepcopy($subObject);
                $v->attach($subClone);
            }
        } else { 
            $v = $propertyValue;
        }
        if ($v !== null) {
            \TYPO3\CMS\Extbase\Reflection\ObjectAccess::setProperty($clone, $propertyName, $v);
        }
    }
    return $clone;
}