DocumentService::goToEditOrPreviewAction

public function goToEditOrPreviewAction($serviceCode, $attachedObjectId = null, $objectId = null, $versionId = null)
{
	$driver = Driver::getInstance();
	$handlersManager = $driver->getDocumentHandlersManager();
	$documentHandler = $handlersManager->getHandlerByCode($serviceCode);
	if (!$documentHandler)
	{
		$this->addError(new Error('There is no document service by code'));
	}

	if (!($documentHandler instanceof OnlyOfficeHandler))
	{
		$this->addError(new Error('Work only with OnlyOffice'));
	}

	if ($this->getErrors())
	{
		return null;
	}

	$canEdit = false;

	if ($versionId)
	{
		$version = DiskVersion::getById($versionId);
		if ($version)
		{
			$objectId = $version->getObjectId();
		}
	}

	if ($objectId)
	{
		$file = DiskFile::getById($objectId);
		if ($file)
		{
			$securityContext = $file->getStorage()->getSecurityContext($this->getCurrentUser());
			$canEdit = $file->canUpdate($securityContext);
		}
	}

	if ($attachedObjectId)
	{
		$attachedObject = DiskAttachedObject::getById($attachedObjectId);
		if ($attachedObject)
		{
			$canEdit = $canEdit || $attachedObject->canUpdate($this->getCurrentUser()->getId());
		}
	}

	if ($canEdit)
	{
		return $this->goToEditAction($serviceCode, $attachedObjectId, $objectId);
	}

	return $this->goToPreviewAction($serviceCode, $attachedObjectId, $objectId, $versionId);
}