If an Entity Reference field has no value, it isn't listed in a GET and gives an error on a PATCH

[BurningDog]

I'm trying to update the value of a field in drupal with a PATCH request and getting the following error message:

detail: "Bad Request."
status: 400
title: "Property current_course cannot be set."
type: "http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.1"

Field current_course is an Entity Reference field which lists the groups a user belongs to. I have defined it in function publicFieldsInfo() as:

    $public_fields['current_course'] = array(
      'property' => 'field_current_course',
      'sub_property' => 'nid',
    );

When the field doesn't have a value and I perform a GET on the API endpoint, current_course doesn't show up at all in the returned JSON. I expect to see at least "current_course":null

However, once the field has a value, the PATCH request works as expected.

[BurningDog]

A similar problem: if a drupal field doesn't have a value then no process_callbacks run.

[martincollar]

Hi @BurningDog I'm just solving same thing, found some walkaround:

Add viewEntity to your resource class:

  public function viewEntity($id) {
    $values = parent::viewEntity($id);

    foreach ($this->getPublicFields() as $public_field_name => $info) {

      if (isset($info["default_value"])
        && isset($info["default_value_callback"])
        && array_key_exists($public_field_name, $values)
        && $info["default_value"] === $values[$public_field_name]
      ) {
        $values[$public_field_name] = static::executeCallback($info["default_value_callback"]);
      }
    }

    return $values;
}

I know for example if uid is 0 than there is FALSE in response, so just add new keys to publicFieldsInfo:

$public_fields['author'] = array(
  'property' => 'uid',
  'process_callbacks' => array(
    '_mymodule_author_callback',
  ),
  'default_value' => FALSE,
  'default_value_callback' => '_mymodule_author_default_callback',
);

What do you think about this?

[rw355]

Having this problem when do POST. It seems a problem with entity module though.

global $user;
$values = array('type' => 'agreement');
$entity = entity_create('node', $values);
$wrapper = entity_metadata_wrapper('node', $entity);
$access = $wrapper->field_entity_ref->access('view', $user);
dvm($access); // this is always false

[chasingmaxwell]

I ran into this issue as well. I've created an issue on the entity module's queue and uploaded a patch which is working for me.

https://www.drupal.org/node/2709457