Drupal 8 Batch Example

I'm in the middle of migrating a Drupal 6 site to Drupal 8 and need to write a batch in Drupal 8 to pull in a bunch of nodes from Drupal 6, so I thought I would document the process to help others.

Related api docs: https://api.drupal.org/api/drupal/core%21includes%21form.inc/group/batch/8

My module's name is disc, so be sure to replace any occurences of it with your module's name.

disc/disc.routing.yml

disc.batch:
  path: '/disc-batch'
  defaults:
    _controller: '\Drupal\disc\Controller\DiscBatchController::content'
    _title: 'Disc Batch'
  requirements:
    _permission: 'administer content'

disc/src/Controller/DiscBatchController.php

<?php

/**
 * @file
 * Contains \Drupal\disc\Controller\DiscBatchController.
 */

namespace Drupal\disc\Controller;

class DiscBatchController {
  public function content() {

    $batch = array(
      'title' => t('Exporting'),
      'operations' => array(
        array('disc_migrate', array('courses', array('foo' => 'bar'))),
      ),
      'finished' => 'disc_migrate_finished_callback',
      'file' => drupal_get_path('module', 'disc') . '/disc.migrate.inc',
    );

    batch_set($batch);
    return batch_process('user');
  }
}

disc/disc.migrate.inc

<?php

function disc_migrate($type, $options = array(), &$context) {

  // Do heavy coding here...
  $message = 'Ready spaghetti...';

  switch ($type) {
    case 'courses':
      $message = 'migrating courses...';
      $context['results'][] = $options;
      break;
    default:
      $message = 'migrating somethine else...';
      break;
  }

  $context['message'] = $message;
}

function disc_migrate_finished_callback($success, $results, $operations) {
  // The 'success' parameter means no fatal PHP errors were detected. All
  // other error management should be handled using 'results'.
  if ($success) {
    $message = \Drupal::translation()->formatPlural(
      count($results),
      'One post processed.', '@count posts processed.'
    );
  }
  else {
    $message = t('Finished with an error.');
  }
  drupal_set_message($message);
  //$_SESSION['disc_migrate_batch_results'] = $results;
}

Testing

Now when I navigate to http://example.com/disc-batch my batch script runs. That's all folks. Maybe I can run faster?