Ajax callback on Views exposed form filter

Question

I'm trying to add an #ajax callback method to my views exposed form filter select box. But it seems the form have some issues with the callback. My code is pretty simple

/**
 * Implements hook_form_FORM_ID_alter() for views_exposed_form.
 */
function mymodule_form_views_exposed_form_alter(&$form, FormStateInterface $form_state) {
  if ($form['#id'] == 'views-exposed-form-viewid') {
    $op = ['hi' => 'hi', 'all' => 'all'];
    $form['test'] = [
      '#type' => 'select',
      '#name' => 'test',
      '#empty_option' => 'none',
      '#options' => $op,
      '#ajax' => [
        'callback' => '_my_call',
        'event' => 'change',
        'wrapper' => 'edit-output-test',
        'progress' => [
          'type' => 'throbber',
        ],
      ],
    ];

    $form['callfield'] = [
      '#type' => 'select',
      '#options' => [],
      '#prefix' => '<div id="edit-output-test">',
      '#suffix' => '</div>',
    ];
  }
}

function _my_call(array &$form, FormStateInterface $form_state) {
  $response = new AjaxResponse();
  $message = 'test';
  $response->addCommand(new HtmlCommand('#edit-output-test', $message));
  return $response;

}

When I try to change the 'test' select box from view edit screen I get the below error

"Symfony\Component\HttpKernel\Exception\HttpException: The specified #ajax callback is empty or not callable. in Drupal\Core\Form\FormAjaxResponseBuilder->buildResponse() (line 67 of /var/www/mypoc/docroot/core/lib/Drupal/Core/Form/FormAjaxResponseBuilder.php)."

When I change the filter from the front end I get the following error

"An unrecoverable error occurred. The uploaded file likely exceeded the maximum file size (32 MB) that this server supports."

And I see a lot of similar issues -

Ajax callback is not working on views exposed filters

Ajax submission leads to => An unrecoverable error occurred. The uploaded file likely exceeded the maximum file size (2 MB) that this server supports

Any working example would be great! Thanks.

Answer 1

Sounds like there is an ongoing core issue queue - https://www.drupal.org/project/drupal/issues/2842525

After applying the patch - https://www.drupal.org/files/issues/2020-03-27/2842525-83.patch this seems to work.