Symfony2: How to display/download a BLOB field

问题:

For my client I have to use blob storage for some various files.

So I have created a independent bundle with a Blob class extends Doctrine\DBAL\Types\Type. and with a boot function in the bundle class.

That works pretty fine I can write in the database Blob datas.

But I can't download any document after :/

I have got:

public function downloadAction($id) {
    $em = $this->getDoctrine()->getManager();

    /* @var $entity Document */
    $entity = $em->getRepository('Lille3SapBundle:Document')->find($id);

    if (!$entity) {
        throw $this->createNotFoundException('Unable to find Document entity.');
    }

    $file = $entity->getFichier();

    $response = new \Symfony\Component\HttpFoundation\Response($file, 200, array(
        'Content-Type' => 'application/octet-stream',
        'Content-Length' => sizeof($file),
        'Content-Disposition' => 'attachment; filename="'.$entity->getNomDocument().'"',
    ));

    return $response;
}

and I have got an Exception: The Response content must be a string or object implementing __toString(), "resource" given.

in fact, the $file values is not the expected BLOB but something like Resource id #123

-> I have check blob data fields values, and they are ok in the database

So how can I force in the controller to have the blob row and not a Resource id #111

回答1:

You can still use BLOB field for your field in DB as you initially planned.

In createAction store data as usual (with no base64_encode()):

$stream = fopen($entity->getFichier(),'rb');
$entity->setFichier(stream_get_contents($stream));

and in downloadAction just use:

$file = $entity->getFichier();
$response = new \Symfony\Component\HttpFoundation\Response(stream_get_contents($file), 200, array(
    'Content-Type' => 'application/octet-stream',
    'Content-Length' => sizeof($file),
    'Content-Disposition' => 'attachment; filename="'.$entity->getNomDocument().'"',
));

return $response;

Explanation:

BLOB fields are treated as resource variable which have no __toString() implementation.

gettype($file) -> "resource"
get_resource_type($file) -> "stream"

stream_get_contents($file) makes the magic here: gets STRING content from resource variable.

回答2:

Okay, I have got a (very uggly) solution:

Firstly: I changed the data type blob to text for the file attribute of Document entity.

Secondly: in createAction I've changed the setFichier call:

$stream = fopen($entity->getFichier(),'rb');
$entity->setFichier(base64_encode(stream_get_contents($stream)));

Thirdly: in downloadAction, I decode the text base64 text field:

$file = $entity->getFichier();              
$response = new \Symfony\Component\HttpFoundation\Response(base64_decode($file), 200, array(
        'Content-Type' => 'application/octet-stream',
        'Content-Length' => sizeof($file),
        'Content-Disposition' => 'attachment; filename="'.$entity->getNomDocument().'"',
));

return $response;

And now I can persist and download files as blob way...