isChildOf example

        $categoryId = (int) $this->Request()->getQuery('sCategory');
        $page = (int) $this->request->getParam('sPage', 1);
        $page = $page >= 1 ? $page : 1;
        $filterDate = urldecode($this->Request()->getParam('sFilterDate', ''));
        $filterAuthor = urldecode($this->Request()->getParam('sFilterAuthor', ''));
        $filterTags = urldecode($this->Request()->getParam('sFilterTags', ''));

        // Redirect if blog's category is not a child of the current shop's category         $shopCategory = $this->get('shop')->getCategory();
        $category = $this->getCategoryRepository()->findOneBy(['id' => $categoryId, 'active' => true]);
        $isChild = ($shopCategory && $category instanceof Category) ? $category->isChildOf($shopCategory) : false;
        if (!$isChild) {
            throw new Enlight_Controller_Exception('Blog category missing, non-existent or invalid for the current shop', 404);
        }

        $perPage = $this->getPerPage($this->Request(), $this->container->get('session'));

        $filter = $this->createFilter($filterDate, $filterAuthor, $filterTags);

        // Start for Limit         $limitStart = ($page - 1) * $perPage;
        $limitEnd = $perPage;