How do you do a redirect after a batch job?

Question

I'm working on setting up a batch process in Drupal 8 that will gather a bunch of remote information for a collection of entities, cache it, and create a list of the results on its own page. The batch process is kicked off from a form using batch_set().

The batch job runs fine, but I'm not sure how to do the redirect at the end. Since Drupal 8 uses RedirectResponse objects or $this->redirect('user.page'); in a controller and the callback for a batch job doesn't have a return type, I'm not sure what to use to trigger the redirect.

I've tried using the url_options value of the batch job definition but that's not working.

$batch = [
  'title'    => $this->t('job running'),
  'init_message' => $this->t('starting job'),
  'operations'  => $ops,
  'finished' => '\Drupal\my_module\MyClass::finished',
  'url_options' => [
    'query' => [
      'destination' => '/job/results',
    ],
  ],
];

Answer 1

Apparently I needed to ask to see the answer: return a RedirectResponse from the finish callback:

public static function finished($success, $results, $operations) {
  if ($success) {
    // Here we do something meaningful with the results.
    $message = t("@count tasks were done.", array(
      '@count' => count($results),
    ));
    drupal_set_message($message);
  }

  return new RedirectResponse('/job/results');
}

As far as I can tell this is an undocumented behavior.

From the helpful comment below, you can also add batch_redirect on the batch array that's either a string or Url object:

$batch = [
  'title'    => $this->t('job running'),
  'init_message' => $this->t('starting job'),
  'operations'  => $ops,
  'finished' => '\Drupal\my_module\MyClass::finished',
  'batch_redirect' => '/job/results',
];

Answer 2

This does not seem to work when creating the batch in a form submit handler, the redirect part in $batch is simply ignored.

Redirecting from the submit handler like this works for me:

$form_state->setRedirect('route.name');