Doctrine Mongo ODM merge for externally modified data

Question

I'm writing a Symfony2 app that allows mobile users to create and update "Homes" via a REST service. I'm using MongoDB as the storage layer and Doctrine MongoDB ODM to do the Document handling.

The GET /homes/{key} and POST /homes methods are working fine. The problem comes when I attempt to update an existing Home with PUT /homes/{key}.

Here's the current code:

/**
 * PUT /homes/{key}
 *
 * Updates an existing Home.
 *
 * @param Request $request
 * @param string $key
 * @return Response
 * @throws HttpException
 */
public function putHomeAction(Request $request, $key)
{
    // check that the home exists
    $home = $this->getRepository()->findOneBy(array('key' => (int) $key));

    // disallow create via PUT as we want to generate key ourselves
    if (!$home) {
        throw new HttpException(403, 'Home key: '.$key." doesn't exist, to create use POST /homes");
    }

    // create object graph from JSON string
    $updatedHome = $this->get('serializer')->deserialize(
        $request->getContent(), 'Acme\ApiBundle\Document\Home', 'json'
    );

    // replace existing Home with new data
    $dm = $this->get('doctrine.odm.mongodb.document_manager');
    $home = $dm->merge($updatedHome);
    $dm->flush();

    $view = View::create()
        ->setStatusCode(200)
        ->setData($home);

    $response = $this->get('fos_rest.view_handler')->handle($view);
    $response->setETag(md5($response->getContent()));
    $response->setLastModified($home->getUpdated());

    return $response;
}

The JSON string passed to the action is successfully deserialized to my Document object graph by JMSSerializer, but when I attempt the merge & flush, I get the error:

Notice: Undefined index:  in ..../vendor/doctrine/mongodb-odm/lib/Doctrine/ODM/MongoDB/Mapping/ClassMetadataInfo.php line 1265

I've been attempting to follow the documentation here: http://docs.doctrine-project.org/projects/doctrine-mongodb-odm/en/latest/reference/working-with-objects.html#merging-documents

Is there something I need to do to the deserialized Home before attempting to merge it? Is merge the wrong method?

Thanks.

Answer 1

The only way I found to do this is to create a method in your document class that takes the updated document (e.g. $updatedHome) as a parameter and then just copies the required fields over into the existing document (e.g. $home).

So above, the code:

// replace existing Home with new data
$dm = $this->get('doctrine.odm.mongodb.document_manager');
$home = $dm->merge($updatedHome);
$dm->flush();

can be replaced with:

// replace existing Home with new data
$home->copyFromSibling($updatedHome);
$this->getDocumentManager()->flush();

and then it will work.