EntityDeleteFormTrait.php

<?php

namespace Drupal\Core\Entity;

use Drupal\Core\Config\Entity\ConfigDependencyDeleteFormTrait;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Url;

/**
 * Provides a trait for an entity deletion form.
 *
 * This trait relies on the StringTranslationTrait and the logger method added
 * by FormBase.
 *
 * @ingroup entity_api
 */
trait EntityDeleteFormTrait {
    use ConfigDependencyDeleteFormTrait;
    
    /**
     * Gets the entity of this form.
     *
     * Provided by \Drupal\Core\Entity\EntityForm.
     *
     * @return \Drupal\Core\Entity\EntityInterface
     *   The entity.
     */
    public abstract function getEntity();
    
    /**
     * Gets the logger for a specific channel.
     *
     * Provided by \Drupal\Core\Form\FormBase.
     *
     * @param string $channel
     *   The name of the channel.
     *
     * @return \Psr\Log\LoggerInterface
     *   The logger for this channel.
     */
    protected abstract function logger($channel);
    
    /**
     * {@inheritdoc}
     */
    public function getQuestion() {
        return $this->t('Are you sure you want to delete the @entity-type %label?', [
            '@entity-type' => $this->getEntity()
                ->getEntityType()
                ->getSingularLabel(),
            '%label' => $this->getEntity()
                ->label(),
        ]);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getConfirmText() {
        return $this->t('Delete');
    }
    
    /**
     * Gets the message to display to the user after deleting the entity.
     *
     * @return string
     *   The translated string of the deletion message.
     */
    protected function getDeletionMessage() {
        $entity = $this->getEntity();
        return $this->t('The @entity-type %label has been deleted.', [
            '@entity-type' => $entity->getEntityType()
                ->getSingularLabel(),
            '%label' => $entity->label(),
        ]);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCancelUrl() {
        $entity = $this->getEntity();
        if ($entity->hasLinkTemplate('collection')) {
            // If available, return the collection URL.
            return $entity->toUrl('collection');
        }
        else {
            // Otherwise fall back to the default link template.
            return $entity->toUrl();
        }
    }
    
    /**
     * Returns the URL where the user should be redirected after deletion.
     *
     * @return \Drupal\Core\Url
     *   The redirect URL.
     */
    protected function getRedirectUrl() {
        $entity = $this->getEntity();
        if ($entity->hasLinkTemplate('collection')) {
            // If available, return the collection URL.
            return $entity->toUrl('collection');
        }
        else {
            // Otherwise fall back to the front page.
            return Url::fromRoute('<front>');
        }
    }
    
    /**
     * Logs a message about the deleted entity.
     */
    protected function logDeletionMessage() {
        $entity = $this->getEntity();
        $this->logger($entity->getEntityType()
            ->getProvider())
            ->notice('The @entity-type %label has been deleted.', [
            '@entity-type' => $entity->getEntityType()
                ->getSingularLabel(),
            '%label' => $entity->label(),
        ]);
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitForm(array &$form, FormStateInterface $form_state) {
        $this->getEntity()
            ->delete();
        $this->messenger()
            ->addStatus($this->getDeletionMessage());
        $form_state->setRedirectUrl($this->getCancelUrl());
        $this->logDeletionMessage();
    }

}