Ojs\OAIBundle\Controller\DefaultController::listSetsAction PHP Method

    public function listSetsAction(Request $request)
    {
        $fileCache = $this->get('file_cache');
        $data = [];
        /** @var \Doctrine\ORM\EntityManager $em */
        $em = $this->getDoctrine()->getManager();
        $from = $request->get('from', false);
        $until = $request->get('until', false);
        $qb = $em->createQueryBuilder();
        $qb->select("j")->from("OjsJournalBundle:Journal", 'j');
        $qb->andWhere('j.status = ' . JournalStatuses::STATUS_PUBLISHED);
        if ($from) {
            $_from = new \DateTime();
            $_from->setTimestamp(strtotime($from));
            $qb->where($qb->expr()->gte('j.created', ':from'))->setParameter('from', $_from);
        }
        if ($until) {
            $_until = new \DateTime();
            $_until->setTimestamp(strtotime($until));
            $condition = $qb->expr()->lte('j.created', ':until');
            if ($from) {
                $qb->andWhere($condition);
            } else {
                $qb->where($condition);
            }
            $qb->setParameter('until', $_until);
        }
        $paginator = $this->get('knp_paginator');
        $resumptionToken = $request->get('resumptionToken');
        if ($resumptionToken) {
            $currentPage = (int) $fileCache->fetch($resumptionToken);
        } else {
            $currentPage = 1;
        }
        $sets = $paginator->paginate($qb->getQuery(), $currentPage, 100);
        $data['records'] = $sets;
        $key = md5(StringHelper::generateKey());
        $fileCache->save($key, $currentPage + 1, 60 * 60 * 24);
        $data['resumptionToken'] = $key;
        $data['isLast'] = $sets->getTotalItemCount() >= $currentPage * 100 ? true : false;
        $data['currentPage'] = $currentPage;
        $data['metadataPrefix'] = $request->get('metadataPrefix', 'oai_dc');
        return $this->response('OjsOAIBundle:Default:sets.xml.twig', $data);
    }