Paragraphs

Introduction

Paragraphs are those special things that allow you to blend fields together e.g. count and unit of measure so you can store values like 5 kilograms or 7 years etc. Often they are used like nodes where you define the fields and fill them with data that get displayed on the screen for things like carousels or events.

Load a node and find the terms referenced in a paragraph in a term reference field

Here we loop thru all the instances of my paragraph reference and grab the term in the paragraph.

use Drupal\taxonomy\Entity\Term;

foreach ($node->get('field_my_para')->referencedEntities() as $ent){
  $term = Term::load($ent->$field_in_paragraph->target_id);
  $name = $term->getName();
  print_r($name);
}

Find all the long text fields that have a certain string

In this code snippet from an issue in the entity embed module the author loads all the fields of type string_long, text_long, and text_with_summary and then queries for nodes with the value data-entity-embed-display-settings="". The code then removes the string and saves the node. It is a useful example because it shows how to find all the fields of a certain type.

Please note that I have not tested this code so it may not be perfect.

<?php

/**
 * Example batch update hook.
 */
function just_an_example(&$sandbox) {
  // Get the entity type manager and node storage.
  $entity_type_manager = \Drupal::entityTypeManager();
  $node_storage = $entity_type_manager->getStorage('node');
  $limit = 100;

  // Initialize the sandbox if it's the first run.
  if (!isset($sandbox['total'])) {
    // Load all fields of type string_long, text_long, and text_with_summary.
    $string_long_fields = array_map(fn ($field) => $field->getName(),
      $entity_type_manager
        ->getStorage('field_storage_config')
        ->loadByProperties([
          'entity_type' => 'node',
          'type' => 'string_long',
        ])
    );
    $text_long_fields = array_map(fn ($field) => $field->getName(),
      $entity_type_manager
        ->getStorage('field_storage_config')
        ->loadByProperties([
          'entity_type' => 'node',
          'type' => 'text_long',
        ])
    );
    $text_with_summary_fields = array_map(fn ($field) => $field->getName(),
      $entity_type_manager
        ->getStorage('field_storage_config')
        ->loadByProperties([
          'entity_type' => 'node',
          'type' => 'text_with_summary',
        ])
    );

    // Merge all field names into a single array.
    $sandbox['fields'] = array_merge($string_long_fields, $text_long_fields, $text_with_summary_fields);

    // Initialize bundles array.
    $sandbox['bundles'] = [];
    foreach ($sandbox['fields'] as $field_name) {
      // Load field storage config and get bundles for each field.
      $field_storage = $entity_type_manager->getStorage('field_storage_config')->load($field_name);
      if ($field_storage) {
        $sandbox['bundles'] = array_merge($sandbox['bundles'], $field_storage->getBundles());
      }
    }

    // Initialize counters.
    $sandbox['current'] = $sandbox['count'] = $sandbox['changed'] = 0;

    // Initialize node IDs array.
    $sandbox['nids'] = [];
    foreach ($sandbox['fields'] as $field) {
      // Query for nodes with specific field values and add to node IDs array.
      $query = \Drupal::database()->select("node__{$field}", 'f')
        ->fields('f', ['entity_id'])
        ->condition("f.{$field}_value", 'data-entity-embed-display-settings=""', 'REGEXP BINARY')
        ->condition('f.bundle', $sandbox['bundles'], 'IN');
      $sandbox['nids'] = array_merge($sandbox['nids'], $query->execute()->fetchCol());
    }

    // Remove duplicate node IDs and sort them.
    $sandbox['nids'] = array_unique($sandbox['nids']);
    sort($sandbox['nids']);
    $sandbox['total'] = count($sandbox['nids']);
  }

  // Query for nodes to process in the current batch.
  $nids = $node_storage->getQuery()
    ->accessCheck(FALSE)
    ->range(0, $limit)
    ->condition('nid', $sandbox['nids'], 'IN')
    ->condition('nid', $sandbox['current'], '>=')
    ->sort('nid', 'ASC');
  $nodes = $nids->execute();
  $nodes = $node_storage->loadMultiple($nodes);

  // Process each node.
  foreach ($nodes as $node) {
    $languages = $node->getTranslationLanguages();

    // Process each language translation of the node.
    foreach ($languages as $langcode => $lang_obj) {
      $cs_node = $node->getTranslation($langcode);
      $changed_node = FALSE;

      // Process each field in the node.
      foreach ($sandbox['fields'] as $field_name) {
        if ($cs_node->hasField($field_name)) {
          $value = $cs_node->get($field_name)->getValue();
          $changed_field = FALSE;

          // Check and update field values.
          foreach ($value as &$content) {
            if (preg_match_all('/data-entity-embed-display-settings=""/', $content['value'], $matches)) {
              foreach ($matches[0] as $replacement) {
                // Remove the match and flag for saving.
                $content['value'] = str_replace($replacement, '', $content['value']);
                $changed_field = $changed_node = TRUE;
              }
            }
          }

          // Save the updated field value.
          if ($changed_field) {
            $cs_node->set($field_name, $value);
          }
        }
      }

      // Save the node if any field was changed.
      if ($changed_node) {
        $sandbox['changed']++;
        $cs_node->save();
      }
    }

    // Update the current node ID and increment the count.
    $sandbox['current'] = $node->id();
    $sandbox['count']++;
  }

  // Update the progress and display status messages.
  $sandbox['#finished'] = empty($sandbox['total']) ? 1 : ($sandbox['count'] / $sandbox['total']);
  \Drupal::messenger()->addStatus($sandbox['count'] . ' nodes processed out of ' . $sandbox['total']);
  \Drupal::messenger()->addStatus($sandbox['changed'] . ' nodes altered');
}

Load a node and retrieve a paragraph field

Because paragraphs and nodes are both entities, the pattern is the same. You load the entity (node or paragraph) and then simply reference the field name e.g. myentity->field_blah

From /Users/selwyn/Sites/inside-mathematics/themes/custom/danaprime/danaprime.theme

These are a little different from regular fields. Generally you want to get their target_id which will tell you the pid or paragraph id. Here are two different ways to load a video_collection_node and go to retrieve a field field_related_lessons which holds paragraphs of type related_lessons:

$video_collection_node = Node::load($video_collection_nid);

//This gives you a bunch of \Drupal\entity_reference_revisions\EntityReferenceRevisionsFieldItemList items
$lessons = $video_collection_node->field_related_lessons;
//or
$lessons = $video_collection_node->get('field_related_lessons');

foreach ($lessons as $lesson) {
  $paragraph_revision_ids[] = $lesson->target_revision_id;
}

Paragraphs use the contributed Entity Reference Revisions module to reference paragraphs and it is very important to use the target_revision_id property when referencing paragraphs. Alternatively, the entity computed property can be used to retrieve the paragraph entity itself.

OR

//This gives you an array of arrays [['target_id' => '348','target_revision_id' => '348'],['target_id' => '349','target_revision_id' => '349'] ]
$lessons = $video_collection_node->get('field_related_lessons')->getValue();
foreach ($lessons as $lesson) {
  $paragraph_revision_ids[] = $lesson['target_revision_id'];
}

Collecting them like this is only an example, while the loadMultiple method exists on entity storage objects, there is no loadMultipleRevisions method.

// This gives you null! - don't do this.
$lessons = $video_collection_node->get('field_related_lessons')->value;

Note

Note. getValue() here will get you the nid buried in a result array of arrays like result[0]['target_revision_id'] - quicker to just grab ->target_revision_id

Load a node and grab a paragraph field to find the nid in an entity reference field

From /Users/selwyn/Sites/inside-mathematics/themes/custom/danaprime/danaprime.theme - Continuing from above, I load a node, grab it's field field_related_lessons which holds paragraphs of type related_lessons and grab it's field field_lesson. That field has a target_id which is the nid for the entity reference field. Phew!:

//Grab the related lessons from the collection.
$video_collection_node = Node::load($video_collection_nid);
$lessons = $video_collection_node->field_related_lessons;
$storage = \Drupal::entityTypeManager()->getStorage('paragraph');
foreach ($lessons as $lesson) {
  //Load each paragraph and get the nids from them.
  $paragraph = $lesson->entity;
  $related_lessons_nid = $paragraph->field_lesson->target_id;
  $related_lessons_nids[] = $related_lessons_nid;
}

//This should have an array of nids for video_details.
$variables['related_lessons_pids'] = $pids;
$variables['related_lessons_nids'] = $related_lessons_nids;

Loop through the paragraphs in a node

This code is from a hook_preprocess_node function in a .theme file. It loads a node and then loops through the paragraphs in a field field_related_lessons and then grabs the title of the paragraph.

<?php

use Drupal\Core\Render\Element;

/**
 * Implements hook_preprocess_node().
 */
function abc_preprocess_node(&$variables) {

  /** @var \Drupal\node\Entity\Node $node */
  $node = $variables['node'];
  $bundle = $node->bundle();
  $view_mode = $variables['view_mode'];

  // Check the there is a field_content field.
  if (isset($variables['content']['field_content'])) {
    $content_tabs = [];
    // Loop through each instance of the field_content field.
    foreach (Element::children($variables['content']['field_content']) as $idx) {
      /** @var \Drupal\Core\Entity\EntityInterface $entity */
      // Grab each paragraph.
      $entity = $variables['content']['field_content'][$idx]['#paragraph'];

      // Get the paragraph's human readable type (not machine name).
      $bundle_label = \Drupal::entityTypeManager()
        ->getStorage($entity->getEntityType()->getBundleEntityType())
        ->load($entity->bundle())
        ->label();

      // For staff_profile content, strip off the "Staff Profile" prefix.
      if ($bundle === 'staff_profile') {
        // This makes "Staff Profile Staff Resources" into "Resources".
        $bundle_label = preg_replace('#^(Staff Profile )#i', '', $bundle_label);

        $variables['offset'] = 0;
        // Check if there is a title term on the node.
        if (($title_term = $node->get('field_staff_profile_title')->entity) !== NULL) {
          // If the title term has a field_global field and it is set to 1, offset the first tab.
          if ($title_term->hasField('field_global') && $title_term->get('field_global')->getString() == '1') {
            $variables['offset'] = 1;
          }
        }
      }
      ...

Add validation for paragraph fields

Here we want to perform validation when a node is added or edited so we use hook_form_alter to add a validation function to the form. In this case, we are adding a validation function to a node form with the id node_staff_profile_form and node_staff_profile_edit_form. We add a class to the form so we can target it with CSS and then add a validation function _ccr_admin_enhancements_area_of_expertise_validate to the form.

Note

The validate function fires at various times including when a paragraph is added, removed or closed. We check for these conditions and then perform our validations.

In abc_admin_enhancements.module:

/**
 * Implements hook_form_alter().
 */
function ccr_admin_enhancements_form_node_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  if ($form_id === 'node_staff_profile_form' || $form_id === 'node_staff_profile_edit_form') {
    $form['#attributes']['class'][] = 'staff-profile-form';
    $form['#validate'][] = '_abc_admin_enhancements_area_of_expertise_validate';
  }
}

/**
 * Validate the area of expertise field.
 */
function _abc_admin_enhancements_area_of_expertise_validate(&$form, FormStateInterface &$form_state) {
  // Don't perform validations if the field doesn't exist.
  if (!($form_state->hasValue('field_areas_of_expertise'))) {
    return;
  }
  if ($form_id === 'node_staff_profile_form' || $form_id === 'node_staff_profile_edit_form') {
    $form['#attributes']['class'][] = 'staff-profile-form';
    $form['#validate'][] = '_ccr_admin_enhancements_area_of_expertise_validate';

    /*
    * Special primary titles: Assistant Research Physician, Associate Research
    *  Physician, Senior Research Physician, OR Staff Clinician (Contr).
    */
    $special_primary_titles = [2477, 2478, 2558, 2651];

    $profile_type = $form_state->getValue('field_staff_profile_type')[0]['target_id'] ?? NULL;
    $ccr_primary_title = $form_state->getValue('field_staff_profile_title')[0]['target_id'] ?? NULL;
    // Some validations will not apply to Other Staff profiles.
    $is_other_staff = !empty($profile_type) && $profile_type == 2575;

    $button = $form_state->getTriggeringElement();
    // Check what paragraph button was pressed: add, remove or closed.
    if (!empty($button)) {
      if ( isset($button['#paragraphs_mode']) && $button['#paragraphs_mode'] === 'remove') {
        // We don't need to validate on paragraph removal.
        return;
      }
      else if ($button['#name'] === 'field_areas_of_expertise_area_of_expertise_add_more') {
        // We don't need to validate on paragraph addition.
        return;
      }
    }

    $values = $form_state->getValue('field_areas_of_expertise');

    // Paragraphs come to us indexed by a number, not necessarily zero-based.
    $first = TRUE;
    // Loop through each area of expertise paragraph.
    foreach ($values as $i => $value) {
      
      // Disease focus is required for first area of expertise for certain profiles.
      if ($first) {
        if (empty($disease_focus) && $is_other_staff && in_array($ccr_primary_title, $special_primary_titles)) {
          $form_state->setErrorByName('field_areas_of_expertise][' . $i . '][subform][field_disease_focus', 'Area of Expertise: Disease Focus is required for this profile type.');
          continue;
        }
      }

      // At least one of these fields must be filled in.
      if (empty($custom_text) && empty($research_area) && empty($disease_focus)) {
        $form_state->setErrorByName('field_areas_of_expertise][' . $i . '][subform', 'Area of Expertise: One of these options must be selected.');
        continue;
      }


    }
  }

Load a node and find the terms referenced in a paragraph in a term reference field

Here we loop thru all the instances of my paragraph reference and grab the term in the paragraph.

foreach ($node->get('field_my_para')->referencedEntities() as $ent){
  $term = $ent->$field_in_paragraph->entity;
  $name = $term->getName();
  print_r($name);
}

Reference

Great Cheat sheets

• Various ways of updating field values in Drupal 8 and 9 - Nov 2020
• Entity query cheat sheet from Metal Toad - Nov 2017
• Drupalsun: Drupal entity API cheat sheet - Jul 2018