Export books with chapters to json files in Zip apchive

ExportBooksController.php

<?php

namespace App\Controller;

use App\Entity\BibleBook;
use Symfony\Component\Filesystem\Filesystem;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\Routing\Annotation\Route;

class ExportBooksController extends Controller
{
    /**
     * @Route("/test")
     */
    public function test(Filesystem $filesystem)
    {
        $cacheDir = $this->getParameter('kernel.cache_dir');
        $books = $this->getDoctrine()->getManager()->getRepository(BibleBook::class)->findAll();

        $files = [];
        foreach ($books as $key => $book) {
            $bookName = $cacheDir . '/books/book_'. ($key + 1) . '.json';
            $json = $this->json(
                $book,
                200,
                [],
                ['single' => true]
            );
            $filesystem->dumpFile($bookName, $json->getContent());
            $files[] = $bookName;
        }

        $zip = new \ZipArchive();
        $zipName = $cacheDir . "/books/Books-".(new \DateTime())->format("d-m-Y").'.zip';
        $zip->open($zipName, \ZipArchive::CREATE);
        foreach ($files as $file) {
            $zip->addFromString(basename($file), file_get_contents($file));
        }
        $zip->close();

        return $this->file($zipName);
    }
}