Drupal 8: Создание псевдо-полей (Extra Fields)

<?php

/**
 * @file
 * Main file for hooks and custom functions.
 */

use Drupal\Core\Entity\Display\EntityViewDisplayInterface;
use Drupal\Core\Entity\Entity\EntityFormDisplay;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\node\Entity\NodeType;

/**
 * Implements hook_entity_extra_field_info().
 */
function dummy_entity_extra_field_info() {
  $extra = [];

  foreach (NodeType::loadMultiple() as $bundle) {
    $extra['node'][$bundle->id()]['display']['estimated_read_time'] = [
      'label' => t('Estimated read time'),
      'description' => t('Calculate estimated read time'),
      'weight' => 100,
      'visible' => FALSE,
    ];

    $extra['node'][$bundle->id()]['form']['simple_captcha'] = [
      'label' => t('Simple captcha'),
      'weight' => 100,
    ];
  }

  return $extra;
}

/**
 * Implements hook_ENTITY_TYPE_view().
 */
function dummy_node_view(array &$build, EntityInterface $entity, EntityViewDisplayInterface $display, $view_mode) {
  if ($display->getComponent('estimated_read_time') && $entity->hasField('body')) {
    if ($entity->body->isEmpty()) {
      $value = t("Can't be calculated because body field is empty");
    }
    else {
      // Average word per minute reading for all languages.
      // @see https://en.wikipedia.org/wiki/Words_per_minute
      $word_per_minute = 184;
      $word_count = str_word_count(strip_tags($entity->body->value));
      $estimated_read_time = floor(($word_count / $word_per_minute) * 60);
      $value = \Drupal::translation()
        ->formatPlural($estimated_read_time, '1 second', '@count seconds');
    }

    $build['estimated_read_time'] = [
      '#type' => 'markup',
      '#markup' => "<p><strong>ERT:</strong> {$value}</p>",
    ];
  }
}

/**
 * Implements hook_form_BASE_FORM_ID_alter().
 */
function dummy_form_node_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  $storage = $form_state->getStorage();
  if (!empty($storage['form_display']) && $storage['form_display'] instanceof EntityFormDisplay) {
    $form_display = $storage['form_display'];
    if ($component = $form_display->getComponent('simple_captcha')) {
      $form['simple_captcha'] = [
        '#type' => 'textfield',
        '#title' => t('Simple captcha'),
        '#default_value' => t('Empty this field to submit the form'),
        '#weight' => $component['weight'],
      ];
      $form['#validate'][] = '_dummy_simple_captcha_validation';
    }
  }
}

/**
 * Validation for captcha.
 */
function _dummy_simple_captcha_validation(&$form, FormStateInterface $form_state) {
  if (strlen($form_state->getValue('simple_captcha'))) {
    $form_state->setError($form['simple_captcha'], t("You don't pass captcha validation"));
  }
}