Programatically initialising paragraph field in drupal 8

Question

I would like to programatically populate a paragraph field with a default value for one of my content types.

I came up with the following solution:

use \Drupal\Node\NodeInterface;
use \Drupal\paragraphs\Entity\Paragraph;

function my_site_node_create(NodeInterface $node) {
    switch ($node->getType()){
        case 'my_content_type':
            $paragraph = Paragraph::create([
                'type' => 'references',  // paragraph type machine name
                'field_references_title' => [  // paragraph's field machine name
                    'value' => 'Some examples of what we have done' // body field value
                ],
            ]);
            $paragraph->save();

            $node->set('field_paragraphs_content', [
                [
                    'target_id' => $paragraph->id(),
                    'target_revision_id' => $paragraph->getRevisionId(),
                ],
            ]);
            break;
    }

}

This code seems to work but im worried I might be creating useless Paragraph-entities when the user doesn't save this node (because of the '$paragraph->save()').

How can I avoid this?

Answer 1

You should be able to rely on the auto-creating of new paragraphs, instead of assinging the ID, do not save the paragraph and assign it with 'entity' => $paragraph.

This should then actually save the paragraph when the node is saved.

Answer 2

Inspired in https://www.drupal.org/project/paragraphs_tools I created the next hook which worked for me. Basically instead for a $node->set it calls the appendItem from the paragraph field.

/**
 * Implements hook_entity_prepare_form().
 *
 * @param EntityInterface $entity
 * @param string $operation
 * @param FormStateInterface $form_state
 */
function example_module_entity_prepare_form(EntityInterface $entity, $operation, FormStateInterface $form_state) {
  $bundles = ['blockherotertiary', 'blockblogpost'];
  $entity_manager = \Drupal::entityManager();
  $langcode = $form_state->get('langcode');

  $field = $entity->get('field_blocks');
  $target_type = $field->getSetting('target_type');

  foreach ($bundles as $bundle_name) {
    // Create paragraph and display.
    $entity_type = $entity_manager->getDefinition($target_type);
    $bundle_key = $entity_type->getKey('bundle');

    /** @var FieldableEntityInterface $paragraphs_entity */
    $paragraphs_entity = $entity_manager->getStorage($target_type)->create(array(
      $bundle_key => $bundle_name,
      'langcode' => $langcode,
    ));

    // Field values.
    $field->appendItem($paragraphs_entity);
  }

}