EntityLabel.php

<?php

namespace Drupal\views\Plugin\views\field;

use Drupal\Core\Entity\EntityMalformedException;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\Core\Entity\Exception\UndefinedLinkTemplateException;
use Drupal\Core\Form\FormStateInterface;
use Drupal\views\Attribute\ViewsField;
use Drupal\views\ResultRow;
use Drupal\views\ViewExecutable;
use Drupal\views\Plugin\views\display\DisplayPluginBase;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Field handler to display entity label optionally linked to entity page.
 */
class EntityLabel extends FieldPluginBase {
    
    /**
     * Array of entities that reference to file.
     *
     * @var array
     */
    protected $loadedReferencers = [];
    
    /**
     * EntityTypeManager class.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * Constructs an EntityLabel object.
     *
     * @param array $configuration
     *   A configuration array containing information about the plugin instance.
     * @param string $plugin_id
     *   The plugin_id for the plugin instance.
     * @param mixed $plugin_definition
     *   The plugin implementation definition.
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, EntityTypeManagerInterface $entity_type_manager) {
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->entityTypeManager = $entity_type_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('entity_type.manager'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function init(ViewExecutable $view, DisplayPluginBase $display, ?array &$options = NULL) {
        parent::init($view, $display, $options);
        $this->additional_fields[$this->definition['entity type field']] = $this->definition['entity type field'];
    }
    
    /**
     * {@inheritdoc}
     */
    protected function defineOptions() {
        $options = parent::defineOptions();
        $options['link_to_entity'] = [
            'default' => FALSE,
        ];
        return $options;
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildOptionsForm(&$form, FormStateInterface $form_state) {
        $form['link_to_entity'] = [
            '#title' => $this->t('Link to entity'),
            '#description' => $this->t('Make entity label a link to entity page.'),
            '#type' => 'checkbox',
            '#default_value' => !empty($this->options['link_to_entity']),
        ];
        parent::buildOptionsForm($form, $form_state);
    }
    
    /**
     * {@inheritdoc}
     */
    public function render(ResultRow $values) {
        $type = $this->getValue($values, $this->definition['entity type field']);
        $value = $this->getValue($values);
        if (empty($this->loadedReferencers[$type][$value])) {
            return;
        }
        
        /** @var \Drupal\Core\Entity\EntityInterface $entity */
        $entity = $this->loadedReferencers[$type][$value];
        if (!empty($this->options['link_to_entity'])) {
            try {
                $this->options['alter']['url'] = $entity->toUrl();
                $this->options['alter']['make_link'] = TRUE;
            } catch (UndefinedLinkTemplateException $e) {
                $this->options['alter']['make_link'] = FALSE;
            } catch (EntityMalformedException $e) {
                $this->options['alter']['make_link'] = FALSE;
            }
        }
        return $this->sanitizeValue($entity->label());
    }
    
    /**
     * {@inheritdoc}
     */
    public function preRender(&$values) {
        parent::preRender($values);
        $entity_ids_per_type = [];
        foreach ($values as $value) {
            if ($type = $this->getValue($value, 'type')) {
                $entity_ids_per_type[$type][] = $this->getValue($value);
            }
        }
        foreach ($entity_ids_per_type as $type => $ids) {
            $this->loadedReferencers[$type] = $this->entityTypeManager
                ->getStorage($type)
                ->loadMultiple($ids);
        }
    }

}