How to save pdf files with Sonata Media Bundle

I tried to save my pdf files into the file system of sonata media bundle and insert the correct database entry.

I created my file with dompdf as following:

$dompdf = new Dompdf($pdfOptions);
$html = $this->renderView("pdf/hrprotokoll.html.twig", [
      'result' => $result,
      'vals' => $vals,
      'title' => 'Prüfprotokoll',
      'item' => $item,
      ]);

$dompdf->loadHtml($html);
$dompdf->setPaper('A4', 'portrait');
$dompdf->render();
$output = $dompdf->output();
$publicDirectory = $request->server->get('DOCUMENT_ROOT') . '/uploads/hrprotokolle/'.$this->getUser()->getStandort()->getId();
$pdfFilepath =  $publicDirectory . '/'. time().'.pdf';
$file = time().'.pdf';
file_put_contents($pdfFilepath, $output);

ok, now the file is saved correctly without errors. The question now is how to manage this file with Sonata MediaBundle. Ive tried the following:

$mediaManager = new MediaManager();
$media = new Media();
$media->setBinaryContent($file);
$media->setContext('default');
$media->setProviderName('sonata.media.provider.file');
$mediaManager->save($media);

Error:

Too few arguments to function Sonata\Doctrine\Model\BaseManager::__construct(), 0 passed... ($mediaManager)

Im not able to set the correct way. Anyone have an idea to solve this problem? Thx

The problem was: $mediaManager (service sonata.media.manager.media) cant autowire so you have to do this manually.

at first check this service in your terminal and find informations about this service by typing the following:

 php bin/console debug:container sonata.media.manager.media

The Result is:

Service ID       sonata.media.manager.media
Class            Sonata\MediaBundle\Entity\MediaManager

Ok, now go to your services.yaml and create the alias:

Sonata\MediaBundle\Entity\MediaManager: '@sonata.media.manager.media' 

Its done. Now you can inject the MediaManager and it works for me:

use Sonata\MediaBundle\Entity\MediaManager;

private $mediaManager;

public function __construct(MediaManager $mediaManager)
{
    $this->mediaManager = $mediaManager;
}

$media = new Media(); 
$this->mediaManager->save($media);