publication_date.module

<?php

/**
 * @file
 * Add a field to nodes containing the publication date.
 */

use Drupal\Core\Field\BaseFieldDefinition;

/**
 * Define the value stored in the database when a node is unpublished and no
 * publication date has been set. We use the largest number that the database
 * field can hold so unpublished nodes will appear newer than published nodes
 * when sorted by publication date.
 *
 * @note: This is going to trigger the Year 2038 problem.
 */
define('PUBLICATION_DATE_DEFAULT', 2147483647);

/**
 * Implements hook_entity_base_field_info().
 *
 * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
 *
 * @return array
 */
function publication_date_entity_base_field_info(\Drupal\Core\Entity\EntityTypeInterface $entity_type) {
  $fields = [];

  if ($entity_type->id() == 'node') {
    $fields['published_at'] = BaseFieldDefinition::create('published_at')
      ->setLabel(t('Published on'))
      ->setDescription(t('Keep the publication timestamp for each node.'))
      ->setRevisionable(TRUE)
      ->setTranslatable(TRUE)
      ->setDisplayOptions('view', array(
        'label' => 'hidden',
        'type' => 'timestamp',
        'weight' => 0,
      ))
      ->setDisplayConfigurable('view', TRUE)
      ->setDisplayOptions('form', array(
        'type' => 'publication_date_timestamp',
        'weight' => 10,
      ))
      ->setDisplayConfigurable('form', TRUE);
  }

  return $fields;
}

/**
 * Implements hook_form_BASE_ID_alter().
 *
 * Display the publication date on the node edit form.
 * @note: This won't work where you have Display Suite/REL enabled.
 */
function publication_date_form_node_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id) {
  $account = \Drupal::currentUser();
  $node = $form_state->getFormObject()->getEntity();

  if (isset($form['published_at'])) {
    // Check if the user has permission to edit the publication date.
    $form['published_at']['#access'] = $account->hasPermission('set any published on date') || $account->hasPermission('set ' . $node->bundle() . ' published on date');
    $form['published_at']['#group'] = 'revision_information';
  }

  /*
  // Use the popup date picker provided by the Date module, if it is enabled and
  // the user has access to edit the publication date.
  if ($pubdate_access && \Drupal::moduleHandler()->moduleExists('date_popup') && \Drupal::config('publication_date')->get('popup_enable')) {
    // The date popup field requires a date format without the timezone.
    $date_format = 'Y-m-d H:i:s';
    $form['options']['pubdate'] = array(
      '#type' => 'date_popup',
      '#title' => t('Published on'),
      '#description' => t('Leave blank to use the time of form submission.'),
      '#date_type' => DATE_UNIX,
      '#date_timezone' => date_default_timezone(),
      '#date_format' => $date_format,
      '#date_increment' => 1,
      '#date_year_range' => '-' . \Drupal::config('publication_date')->get('year_start') . ':+' . \Drupal::config('publication_date')->get('date_popup_year_end'),
      '#weight' => -1,
      '#access' => TRUE,
    );
  }
  // Falback to a standard text field.
  else {
    $form['options']['pubdate'] = array(
      '#type' => 'textfield',
      '#title' => t('Published on'),
      '#maxlength' => 25,
      '#description' => t('Format: %time. Leave blank to use the time of form submission.', array('%time' => format_date(REQUEST_TIME, 'custom', $date_format))),
      '#weight' => -1,
      '#access' => $pubdate_access,
    );
  }

  // If there is an existing publication date, set it as the default value.
  $form['options']['pubdate']['#default_value'] = empty($published_at) ? '' : format_date($published_at, 'custom', $date_format);

  // If the user can access pubdate, we need to make sure they also have access
  // to the options group.
  if ($pubdate_access && $form['options']['#access'] == FALSE) {
    $form['options']['#access'] = TRUE;
    // Check all fields in the options group and, if access has not been set,
    // set it to FALSE. We don't want to grant access to any extra fields.
    $children = \Drupal\Core\Render\Element::children($form['options']);
    foreach ($children as $key => $value) {
      if (!isset($form['options'][$value]['#access'])){
        $form['options'][$value]['#access'] = FALSE;
      }
    }
  }
  */
}

/**
 * Implements hook_clone_node_alter().
 *
 * Reset the publication date when a node is cloned using the Node Clone module.
 *
 * @see clone.api.php
 */
function publication_date_clone_node_alter(&$node, $context) {
  $node->published_at->value = NULL;
}

/**
 * Implements hook_field_formatter_info_alter().
 */
function publication_date_field_formatter_info_alter(array &$info) {
  $info['timestamp']['field_types'][] = 'published_at';
  $info['timestamp_ago']['field_types'][] = 'published_at';
}