File::attachPreviewAction

public function attachPreviewAction(DiskFile $file): array
{
	$currentUserId = $this->getCurrentUser()->getId();
	$securityContext = $file->getStorage()->getSecurityContext($currentUserId);
	if (!$file->canUpdate($securityContext))
	{
		$this->addError(new Error(Loc::getMessage('DISK_ERROR_MESSAGE_DENIED')));

		return [];
	}

	$previewFileData = $this->request->getFile('previewFile');
	if (!is_array($previewFileData))
	{
		$this->addError(new Error('Could not find preview file in request'));

		return [];
	}

	$result = $file->attachImagePreview($previewFileData);
	if (!$result->isSuccess())
	{
		$this->addErrors($result->getErrors());

	}

	return [];
}