Question

We are using Symfony2 to create an API. When updating a record, we expect the JSON input to represent a serialized updated entity. The JSON data will not contain some fields (for instance, CreatedAt should be set only once when the entity is created – and never updated). For instance, here is an example JSON PUT request:

{"id":"1","name":"anyname","description":"anydescription"}

Here is the PHP code on the Controller that should update the entity according to the JSON above (we are using JMS serializer Bundle):

$supplier = $serializer->deserialize(
    $this->get('request')->getContent(),
    'WhateverEntity',
    'json'
);

The EntityManger understands (correctly) that this is an update request (in fact, a SELECT query is implicitly triggered). The EntityManager also guess (not correctly) that CreatedAt property should be NULLified – it should instead keep the previous one.

How to fix this issue?

Answer 1

I would use the Doctrine\ORM\Mapping\ClassMetadata API to discover existing fields in your entity.
You can do following (I don’t know how JMSSerializerBundle works):

//Unserialize data into $data
$metadata = $em->getMetadataFactory()->getMetadataFor($FQCN);
$id = array();
foreach ($metadata->getIdentifierFieldNames() as $identifier) {
    if (!isset($data[$identifier])) {
        throw new InvalidArgumentException('Missing identifier');
    }
    $id[$identifier] = $data[$identifier];
    unset($data[$identifier]);
}
$entity = $em->find($metadata->getName(), $id);
foreach ($metadata->getFieldNames() as $field) {
    //add necessary checks about field read/write operation feasibility here
    if (isset($data[$field])) {
        //careful! setters are not being called! Inflection is up to you if you need it!
        $metadata->setFieldValue($entity, $field, $data[$field]);
    }
}
$em->flush();