Save data to custom field columns using entity_metadata_wrapper

Question

I have a simple custom module that creates a new field type. The field has multiple columns in the database; the idea is that a user (or code) will enter a single value, and then that value is converted into several different formats and saved to the database columns.

Currently, this is working by using a method from the book Drupal 7 Module Development, where the user's original value is converted using a widget validate function.

It works great when a human is filling out a form; but the problem is, when I try to create an entity in code, using entity_metadata_wrapper, there's no widget, and thus, no widget validate function runs.

It looks like I need to look at hook_field_info and specify a property_type of 'struct' with a custom setter callback, but I can't find any documentation that describes how to use the property or getter/setter callbacks.

How can I use entity metadata wrappers with custom field database columns?

/**
 * Implements hook_field_info().
 */
function device_id_field_info() {
  return array(
    'device_id' => array(
      'label' => t('Device ID'),
      'description' => t('Converts the input device ID and saves it to the 
        database in various formats.'),
      'default_widget' => 'device_id_simple',
      'default_formatter' => 'device_id_raw',
      'default_token_formatter' => 'device_id_combined',
      'property_type' => 'device_id',
      'property_callback' => array('_device_id_property_callback'),
      ),
  );
}

/**
 * Callback to alter the property info of device id fields.
 *
 * @see device_id_field_info().
 */
function _device_id_property_callback(&$info, $entity_type, $field, $instance, $field_type) {
  $name = $field['field_name'];
  $property = &$info[$entity_type]['bundles'][$instance['bundle']]['properties'][$name];

  $property['type'] = ($field['cardinality'] != 1) ? 'list<deviceid>' : 'deviceid';
  $property['getter callback'] = 'entity_metadata_field_verbatim_get';
  $property['setter callback'] = 'entity_metadata_field_verbatim_set';
  $property['property info'] = device_id_property_info();

  unset($property['query callback']);
}

/**
 * Defines info for the properties of the device ID field data structure.
 */
function device_id_property_info($name = NULL) {
  // Build an array of basic property information for the device ID field.
  $properties = array(
    'raw_id' => array(
      'label' => t('Raw input ID'),
    ),
    'esn_hex' => array(
      'label' => t('Converted ESN in hexadecimal format'),
    ),
    'esn_dec' => array(
      'label' => t('Converted ESN in decimal format'),
    ),
    'meid_hex' => array(
      'label' => t('Converted MEID in hexadecimal format'),
    ),
    'meid_dec' => array(
      'label' => t('Converted MEID in decimal format'),
    ),
    'imei_hex' => array(
      'label' => t('Converted IMEI in hexadecimal format'),
    ),
    'imei_dec' => array(
      'label' => t('Converted IMEI in decimal format'),
    ),
    'iccid_hex' => array(
      'label' => t('Converted ICCID in hexadecimal format'),
    ),
    'iccid_dec' => array(
      'label' => t('Converted ICCID in decimal format'),
    ),
  );
}

/**
 * Implements hook_field_is_empty().
 *
 * Pseudo-hook.
 */
function device_id_field_is_empty($item, $field) {
  if ($field['type'] == 'device_id') {
    if (
      empty($item['raw_id']) &&
      empty($item['cap_dec']) && 
      empty($item['cap_hex']) && 
      empty($item['meid_dec']) && 
      empty($item['meid_hex']) && 
      empty($item['imei_dec']) && 
      empty($item['imei_hex']) && 
      empty($item['iccid_dec']) && 
      empty($item['iccid_hex'])) { 
      return TRUE;
    }
  }
  return FALSE;
}

/**
 * Implements hook_field_widget_info().
 */
function device_id_field_widget_info() {
  return array(
    'device_id_simple' => array(
      'label' => t('Device ID text field'),
      'description' => t(
        'Allow the user to enter the device ID, and display it in 
        whatever format it was entered'),
      'field types' => array('device_id'),
      'behaviors' => array(
        'multiple values' => FIELD_BEHAVIOR_DEFAULT,
        'default value' => FIELD_BEHAVIOR_DEFAULT,
        ),
      ),
    );
}

/**
 * Implements hook_field_widget_form().
 *
 * Pseudo hook
 **/
function device_id_field_widget_form(
  &$form, &$form_state, $field, $instance, $langcode, $items, $delta, $element) {

  switch ($instance['widget']['type'] == 'device_id_simple') {

    case 'device_id_simple':
      $element += array(
        '#element_validate' => array('_device_id_wrapper_validate'),
        'device_id_wrapper' => array(
          'input_id' => array(
            '#title' => t('Device ID'),
            '#type' => 'textfield',
            '#default_value' => isset($items[$delta]['raw_id']) ? 
              $items[$delta]['raw_id'] : '',
          ),
        )
      );
    break;
  }
  return $element;
}

function _device_id_wrapper_validate($element, &$form_state) {
  //This function is also called when submitting the field
  //configuration form.  If so, skip validation since it 
  //won't work anyway
  if ($form_state['complete form']['#form_id'] == 'field_ui_field_edit_form') {
    return;
  }

  $values = $form_state['values'];
  $language = $element['#language'];
  $field_name = $element['#field_name'];
  $item = $values[$field_name][$language][$element['#delta']]['device_id_wrapper'];

  foreach ($values[$field_name][$language] as $delta => $item) {
    if (is_array($item)) {
      if (array_key_exists('device_id_wrapper', $item)) {
        $conversion = new deviceIDConversion($item['device_id_wrapper']['input_id']);
        $conversion_values = $conversion->calculate();
        if ($conversion_values) {
          $new_values = array(
            'esn_hex' => isset($conversion_values['ESN_HEX']) ? $conversion_values['ESN_HEX'] : NULL,
            'esn_dec' => isset($conversion_values['ESN_DEC']) ? $conversion_values['ESN_DEC'] : NULL,
            'meid_hex' => isset($conversion_values['MEID_HEX']) ? $conversion_values['MEID_HEX'] : NULL,
            'meid_dec' => isset($conversion_values['MEID_DEC']) ? $conversion_values['MEID_DEC'] : NULL,
            'imei_hex' => isset($conversion_values['IMEI_HEX']) ? $conversion_values['IMEI_HEX'] : NULL,
            'imei_dec' => isset($conversion_values['IMEI_DEC']) ? $conversion_values['IMEI_DEC'] : NULL,
            'iccid_hex' => isset($conversion_values['ICCID_HEX']) ? $conversion_values['ICCID_HEX'] : NULL,
            'iccid_dec' => isset($conversion_values['ICCID_DEC']) ? $conversion_values['ICCID_DEC'] : NULL,
            'raw_id' => $item['device_id_wrapper']['input_id'],
            );
          form_set_value($element, $new_values, $form_state);
        } else {
          form_set_error($field_name, t('Your device ID doesn\'t match a valid format.  Check
            the device ID, verify it\'s correct, and type/scan it again.'));
        }
      }
    }
  }
}

/**
 * Implements hook_field_validate().
 *
 * Pseudo-hook.
 */
function device_id_field_validate($entity_type, $entity, $field, $instance, $langcode, $items, &$errors) {
  foreach ($items as $delta => $item) {
    if (!empty($item['raw_id'])) {
      $conversion = new deviceIDConversion($item['raw_id']);
      $conversion_values = $conversion->calculate();
      if (!$conversion_values) {
        $errors[$field['field_name']][$langcode][$delta][] = array(
          'error' => 'device_id_invalid_format',
          'message' => t('Your device ID doesn\'t match a valid format.  Check
            the device ID, verify it\'s correct, and type/scan it again.'),
        );
      } 
    }
  }
}

Here is some example code I'm using in a test page to work with this content; when I do entity_load(), I can view the contents of the custom field, including the database columns I defined in hook_info(). When I wrap this in entity_metadata_wrapper() and try setting the field value, nothing happens. Also, after wrapping, I can no longer see the field values, even with getPropertyInfo().

$ent = entity_load('node', array('2955'));
$new_ent = entity_metadata_wrapper('node', $ent['2955']);
$new_ent->field_device_id->meid_hex = 'a1000002747883';
$new_ent->save();
dsm($new_ent->getPropertyInfo());

Answer 1

To access a field value from the wrapper try:

$new_ent->field_device_id->meid_hex->value();

or for the whole entity: $entity_object = $new_ent->value();

Answer 2

You can try the following:

$node = node_load($nid);
$wrapper = entity_metadata_wrapper('node', $node);
//- Set Lang
$wrapper->language->set('en');
//- Set Title
$wrapper->title->set('test');
//- Set Body Value
$wrapper->body->set(array('value' => 'Some text', 'format' => 'full_html'));
//- Set Custom field 
$wrapper->your_custom_field_name->set('field value');
$wrapper->save();