Allow for Relative Dates on Default Field Values for Registration Settings

Thanks for the post! This can be done a few different ways. One successful approach I have seen is to override the Node entity class and add your own postSave that looks for a new Event node (just guessing at the content type name) and if it exists, create a new Registration Settings entity with open and close dates from the Event. And then use the new Registration Scheduled Actions submodule to have notifications sent relative to this date. If admins can change the Event date later, then the postSave will need to be smart enough to track Event updates too (not just new ones), and copy any date changes to the Settings entity created earlier. I can post some code if you want to try this approach and aren't comfortable with overriding entity types. Regardless of approach, this is probably custom and not something I could see going into the core Registration module (especially since the new submodule does indeed support relative date notifications - you just need a way to get your open and close dates set).

Here's some code. In my_module.module:

/**
 * Implements hook_entity_type_alter().
 */
function my_module_entity_type_alter(array &$entity_types) {
  // Extend the node entity type.
  if (isset($entity_types['node'])) {
    $entity_types['node']->setClass('Drupal\my_module\Entity\Node');
  }
}

In my_module/src/Entity/Node.php:

namespace Drupal\my_module\Entity;

use Drupal\Core\Datetime\DrupalDateTime;
use Drupal\Core\Entity\EntityStorageInterface;
use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
use Drupal\node\Entity\Node as BaseNode;

use DateTime;
use DateTimeZone;

/**
 * Extends the node entity class.
 */
class Node extends BaseNode {

  /**
   * {@inheritdoc}
   */
  public function postSave(EntityStorageInterface $storage, $update = TRUE) {
    parent::postSave($storage, $update);

    // Assumes that the content type machine name is "event".
    if ($this->bundle() == 'event') {
      if (!$this->get('field_dates')->isEmpty()) {

        // Assumes that field_dates contains the Event start date.
        $date_value = $this->get('field_dates')->first()->getValue()['value'];
        $storage_timezone = new DateTimeZone(DateTimeItemInterface::STORAGE_TIMEZONE);
        $storage_format = DateTimeItemInterface::DATETIME_STORAGE_FORMAT;
        $date = DrupalDateTime::createFromFormat($storage_format, $date_value, $storage_timezone);
        $php_date = $date->getPhpDateTime();

        // Open registration 10 days before the Event starts.
        $open = clone $php_date;
        $open = $open->modify('-10 days')->format($storage_format);

        // Close registration 15 minutes after the Event starts.
        $close = clone $php_date;
        $close = $close->modify('+15 minutes')->format($storage_format);

        $entity_type_manager = \Drupal::entityTypeManager();
        $handler = $entity_type_manager->getHandler('registration', 'host_entity');
        $host_entity = $handler->createHostEntity($this);

        $settings = $entity_type_manager
          ->getStorage('registration_settings')
          ->loadSettingsForHostEntity($host_entity);
        $settings->set('open', $open);
        $settings->set('close', $close);
        $settings->save();
      }
    }
  }

}

Thanks, I'm fine doing it that way if it's not something we want to get into the module. Thanks for the reply!