entityreference_add_child_to_parent.module

<?php

/**
 * @file
 * Entity Reference add child to parent.
 */

/**
 * Implements hook_form_FORMID_alter().
 */
function entityreference_add_child_to_parent_form_field_ui_field_edit_form_alter(&$form, &$form_state, $form_id) {
  if ($form['#field']['type'] != 'entityreference') {
    return;
  }

  $form['instance']['add_child_to_parent_link'] = array(
    '#type' => 'checkbox',
    '#title' => 'Provide a pseudofield link to add the referenced entity and reference parent entity',
    '#description' => 'Check this option if you want a pseudo field to appear in the display settings of this entity that allows to create a referenced entity that will automatically be referenced by this (parent) entity. If this option is set exactly one bundle must be specified in the field settings.',
    '#default_value' => isset($form['#instance']['add_child_to_parent_link']) ? $form['#instance']['add_child_to_parent_link'] : FALSE,
    '#weight' => -9,
  );

  $form['#validate'][] = '_entityreference_add_child_to_parent_field_settings_form_validate';
  $form['#submit'][] = '_entityreference_add_child_to_parent_field_settings_form_submit';

  return $form;
}

/**
 * Extra validate function for field_ui_field_edit_form.
 *
 * Ensure that exactly one bundle is set.
 */
function _entityreference_add_child_to_parent_field_settings_form_validate($form, &$form_state) {
  if ($form_state['values']['instance']['add_child_to_parent_link'] !== 1) {
    // Only validate if the add_child_to_parent_link is set.
    return;
  }

  $bundles = $form_state['values']['field']['settings']['handler_settings']['target_bundles'];
  if (count($bundles) != 1) {
    form_set_error('add_child_to_parent_link', t('A create entity link needs exactly one bundle to be specified.'));
  }
}

/**
 * Extra submit function for field_ui_field_edit_form.
 *
 * Populate the entityreference_add_child_to_parent_entity_types variable.
 */
function _entityreference_add_child_to_parent_field_settings_form_submit($form, &$form_state) {
  $entity = $form_state['values']['instance']['entity_type'];
  $bundle = $form_state['values']['instance']['bundle'];
  $field = $form_state['values']['instance']['field_name'];
  $add_child_to_parent_link = $form_state['values']['instance']['add_child_to_parent_link'];

  $mymodule_types = variable_get('entityreference_add_child_to_parent_entity_types', array());

  // Decide whether to add the setting to the variable
  // entityreference_add_child_to_parent_entity_types.
  if (isset($mymodule_types[$entity][$bundle]) && in_array($field, $mymodule_types[$entity][$bundle])) {
    if ($add_child_to_parent_link !== 1) {
      // Is in variable but not in form: Remove it and flush cache.
      $mymodule_types[$entity][$bundle] = array_diff($mymodule_types[$entity][$bundle], array($field));
      // Cleanup array if necessary.
      $mymodule_types[$entity] = array_filter($mymodule_types[$entity]);
      $mymodule_types = array_filter($mymodule_types);
      variable_set('entityreference_add_child_to_parent_entity_types', $mymodule_types);
    }
  }
  else {
    if ($add_child_to_parent_link === 1) {
      // Is not in variable but is in form: Add it and flush cache.
      $mymodule_types[$entity][$bundle][] = $field;
      variable_set('entityreference_add_child_to_parent_entity_types', $mymodule_types);
    }
  }
  // dpm($mymodule_types, '$mymodule_types');
}

/**
 * Implements hook_field_extra_fields().
 */
function entityreference_add_child_to_parent_field_extra_fields() {
  $extra = array();

  $mymodule_types = variable_get('entityreference_add_child_to_parent_entity_types', array());

  $add_link = array(
    'label' => t('Add entity link'),
    'description' => t("A link to add an entity and populate the parent's reference field."),
    'weight' => -115,
  );
  foreach ($mymodule_types as $entity => $bundles) {
    foreach ($bundles as $bundle => $fields) {
      foreach ($fields as $field) {
        $extra[$entity][$bundle]['display']['entityreference_add_child_link_' . $field] = $add_link;
        $extra[$entity][$bundle]['display']['entityreference_add_child_link_' . $field]['label'] .= ' for ' . $field;
      }
    }
  }

  return $extra;
}

/**
 * Implements hook_entity_view().
 *
 * Generates markup for the pseudofields.
 */
function entityreference_add_child_to_parent_entity_view($entity, $type, $view_mode, $langcode) {
  $entity_type = $entity->content['#entity_type'];
  $entity_bundle = $entity->content['#bundle'];
  $title = entity_label($entity_type, $entity);

  $extrafields = field_extra_fields_get_display($entity_type, $entity_bundle, $view_mode);
  foreach ($extrafields as $extrafield_name => $extrafield) {
    if (strpos($extrafield_name, 'entityreference_add_child_link') !== FALSE) {
      if ($extrafield['visible']) {
        $weight = $extrafield['weight'];

        // Get field name.
        $pos = strlen('entityreference_add_child_link');
        $field_name = substr($extrafield_name, $pos + 1);

        $field_info = field_info_field($field_name);

        $field_entity = $field_info['settings']['target_type'];
        $field_bundle = reset($field_info['settings']['handler_settings']['target_bundles']);

        $entity_info = entity_get_info($field_entity);
        $bundle_label = $entity_info['bundles'][$field_bundle]['label'];
        $entity_label = $entity_info['label'];

        // Get path. Every entity type needs special handling as there is no API
        // that returns the entitie's add entity path.
        // Currently it only supports node and ECK entities.
        if ($field_entity == 'node') {
          $path = 'node/add/' . str_replace('_', '-', $field_bundle);
        }
        // ECK entities.
        elseif (isset($entity_info['bundles'][$field_bundle]['crud']['add']['path'])) {
          $path = $entity_info['bundles'][$field_bundle]['crud']['add']['path'];
        }
        else {
          $path = '';
          // @todo for other entity types.
        }

        // Access control.
        if (drupal_valid_path($path)) {
          $entity_ids = entity_extract_ids($entity_type, $entity);
          // Prepare link.
          $query = array(
            'type' => $entity_type,
            'bundle' => $entity_bundle,
            'eid' => $entity_ids[0],
            'field' => $field_name,
          );
          $query += drupal_get_destination();
          $add_link = l(t('Add @bundle_label for @title', array(
              '@bundle_label' => $bundle_label,
              '@title' => $title,
            )),
            $path, array(
              'attributes' => array(),
              'query' => $query,
            ));

          $entity->content[$extrafield_name] = array(
            '#markup' => $add_link,
            '#weight' => $weight,
          );
        }

      }
    }
  }
}

/**
 * Implements hook_entity_insert().
 *
 * Adds the reference to the parent entity and saves it.
 */
function entityreference_add_child_to_parent_entity_insert($entity, $type) {
  $params = drupal_get_query_parameters();
  $type = (isset($params['type'])) ? check_plain($params['type']) : '';
  $bundle = (isset($params['bundle'])) ? check_plain($params['bundle']) : '';
  $eid = (isset($params['eid'])) ? check_plain($params['eid']) : '';
  $field = (isset($params['field'])) ? check_plain($params['field']) : '';

  if (empty($type) || empty($eid) || empty($field)) {
    return;
  }

  $entity_ids = entity_extract_ids($type, $entity);
  $entity_id = $entity_ids[0];

  // Check that the field can be found in the variable:
  // entityreference_add_child_to_parent_entity_types. If not provide an error
  // message and do not reference this entity in the parent entity.
  $mymodule_types = variable_get('entityreference_add_child_to_parent_entity_types', array());
  if (!in_array($field, $mymodule_types[$type][$bundle])) {
    drupal_set_message(t('The field instance settings for field %field in bundle %bundle for entity %entity do not allow referencing parent entity. The newly created entity is not referenced by its parent.', array(
      '%field' => $field,
      '%bundle' => $bundle,
      '%entity' => $type,
    )), 'error');
    return;
  }

  // Check that the created entity is of the same type and bundle as defined in
  // the parents entity referenced field allowed type.
  // @todo check entity type. There is no easy way given an entity
  // to find its type.
  $original_enity_bundle = $entity->type;
  $field_info = field_info_field($field);
  $field_type = $field_info['settings']['target_type'];
  $field_bundle = reset($field_info['settings']['handler_settings']['target_bundles']);
  if ($original_enity_bundle != $field_bundle) {
    drupal_set_message(t("The entitie's bundle does not match the referenced field's bundle. The newly created entity is not referenced by its parent."), 'error');
    return;
  }

  if (!empty($type) && !empty($eid) && !empty($field)) {
    if (!is_numeric($eid)) {
      drupal_set_message(t('Invalid Entity id. The newly created entity is not referenced by its parent.'), 'error');
      return;
    }
    $entity_wrapper = entity_metadata_wrapper($type, $eid);

    if ($entity_wrapper->value()) {
      // dpm('have identifier');
      if (isset($entity_wrapper->{$field}) && $entity_wrapper->{$field}->validate(array($entity_id))) {
        // dpm('does validate');
        $entity_wrapper->{$field}[] = $entity_id;
        $entity_wrapper->save();
      }
    }
    else {
      drupal_set_message(t('Invalid Entity id. The newly created entity is not referenced by its parent.'), 'error');
      return;
    }
  }

  // throw new Exception("Custom Exception to stop code execution");
}

/**
 * Implements hook_field_delete_instance().
 *
 * Removes the entityreference_add_child_to_parent value from the
 * entityreference_add_child_to_parent_entity_types variable.
 */
function entityreference_add_child_to_parent_field_delete_instance($instance) {
  // Only act on entity reference fields.
  $field = field_read_field($instance['field_name']);
  if ($field['type'] != 'entityreference') {
    return;
  }

  $entity_type = $instance['entity_type'];
  $bundle = $instance['bundle'];
  $field_name = $instance['field_name'];

  $mymodule_types = variable_get('entityreference_add_child_to_parent_entity_types', array());
  if (isset($mymodule_types[$entity_type][$bundle]) && in_array($field_name, $mymodule_types[$entity_type][$bundle])) {
    $mymodule_types[$entity_type][$bundle] = array_diff($mymodule_types[$entity_type][$bundle], array($field_name));
    $mymodule_types[$entity_type] = array_filter($mymodule_types[$entity_type]);
    $mymodule_types = array_filter($mymodule_types);
    variable_set('entityreference_add_child_to_parent_entity_types', $mymodule_types);
  }
}