drupal8_batch_form.php

<?php

namespace Drupal\ln_follow_and_alert\Form;

use Drupal\Core\Batch\BatchBuilder;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * BuildFollowEntitiesBatchForm.
 */
class BuildFollowEntitiesBatchForm extends FormBase {

  /**
   * Batch Builder.
   *
   * @var \Drupal\Core\Batch\BatchBuilder
   */
  protected $batchBuilder;

  /**
   * Node storage.
   *
   * @var \Drupal\node\NodeStorageInterface
   */
  protected $nodeStorage;

  /**
   * BuildFollowEntitiesBatchForm constructor.
   *
   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
   *   The entity type manager.
   *
   * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
   * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
   */
  public function __construct(
    EntityTypeManagerInterface $entity_type_manager
  ) {
    $this->nodeStorage = $entity_type_manager->getStorage('node');
    $this->batchBuilder = new BatchBuilder();
  }

  /**
   * {@inheritdoc}
   *
   * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
   * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
   *
   * @noinspection PhpParamsInspection
   */
  public static function create(ContainerInterface $container) {
    return new static(
      $container->get('entity_type.manager')
    );
  }

  /**
   * {@inheritdoc}
   */
  public function getFormId() {
    return 'ln_build_follow_entities_batch_form';
  }

  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state) {

    $form['help'] = [
      '#markup' => $this->t('Create follow entities for news.'),
    ];

    $form['actions'] = ['#type' => 'actions'];
    $form['actions']['run'] = [
      '#type' => 'submit',
      '#value' => $this->t('Run batch'),
      '#button_type' => 'primary',
    ];

    return $form;
  }

  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    $nids = $this->nodeStorage->getQuery()
      ->condition('type', 'news')
      ->execute();

    $this->batchBuilder
      ->setTitle($this->t('Processing'))
      ->setInitMessage($this->t('Initializing.'))
      ->setProgressMessage($this->t('Completed @current of @total.'))
      ->setErrorMessage($this->t('An error has occurred.'));

    $this->batchBuilder->setFile(
      drupal_get_path('module', 'ln_follow_and_alert') . '/src/Form/BuildFollowEntitiesBatchForm.php'
    );
    $this->batchBuilder->addOperation([$this, 'processItems'], [$nids]);
    $this->batchBuilder->setFinishCallback([$this, 'finished']);

    batch_set($this->batchBuilder->toArray());
  }

  /**
   * Processor for batch operations.
   *
   * @throws \Drupal\Core\Entity\EntityStorageException
   */
  public function processItems($items, array &$context) {
    // Elements per operation.
    $limit = 5;

    // Set default progress values.
    if (empty($context['sandbox']['progress'])) {
      $context['sandbox']['progress'] = 0;
      $context['sandbox']['max'] = count($items);
    }

    // Save items to array which will be changed during processing.
    if (empty($context['sandbox']['items'])) {
      $context['sandbox']['items'] = $items;
    }

    $counter = 0;
    if (!empty($context['sandbox']['items'])) {
      // Remove already processed items.
      if ($context['sandbox']['progress'] != 0) {
        array_splice($context['sandbox']['items'], 0, $limit);
      }

      foreach ($context['sandbox']['items'] as $item) {
        if ($counter != $limit) {
          $this->processItem($item);

          $counter++;
          $context['sandbox']['progress']++;

          $context['message'] = $this->t('Now processing node :progress of :count', [
            ':progress' => $context['sandbox']['progress'],
            ':count' => $context['sandbox']['max'],
          ]);

          // Increment total processed item values. Will be used in finished
          // callback.
          $context['results']['processed'] = $context['sandbox']['progress'];
        }
      }
    }

    // If not finished all tasks, we count percentage of process. 1 = 100%.
    if ($context['sandbox']['progress'] != $context['sandbox']['max']) {
      $context['finished'] = $context['sandbox']['progress'] / $context['sandbox']['max'];
    }
  }

  /**
   * Process single item.
   *
   * @param int|string $nid
   *   An id of Node.
   *
   * @throws \Drupal\Core\Entity\EntityStorageException
   */
  public function processItem($nid) {
    /** @var \Drupal\node\NodeInterface $node */
    $node = $this->nodeStorage->load($nid);
    _news_node_postsave($node);
  }

  /**
   * Finished callback for batch.
   *
   * @noinspection PhpUnusedParameterInspection
   */
  public function finished($success, $results, $operations) {
    $message = $this->t('Number of nodes affected by batch: @count', [
      '@count' => $results['processed'],
    ]);

    $this->messenger()
      ->addStatus($message);
  }

}