Drupal 8 Mailchimp Ajax Signup Block - ajax

Question

I try to ajaxify the Drupal 8 Mailchimp SignUp Block but I stuck with the AjaxResponse.
This is my Form alter hook:
function mailchimp_ajax_form_form_alter(&$form, \Drupal\Core\Form\FormStateInterface &$form_state, $form_id) {
if ($form_id != 'mailchimp_signup_subscribe_block_form') {
return;
}
$form['submit']['#ajax'] = [
'callback' => 'mailchimp_ajax_form_callback',
'prevent' => 'click',
'progress' => array(
'type' => 'throbber',
'message' => t('Submitting data...')
)
];
}
This is my callback function:
function mailchimp_ajax_form_callback(array &$form, \Drupal\Core\Form\FormStateInterface $form_state) {
$response = new \Drupal\Core\Ajax\AjaxResponse();
$response->setContent('Response');
return $response;
}
But in Chrome console there is only an error:
Uncaught AjaxError:
An AJAX HTTP error occurred.
HTTP Result Code: 200
Debugging information follows.
Path: /node?ajax_form=1
StatusText: OK
ResponseText: Response
The Signup works, but my question is how can I get the mailchimp response and put it in a valid AjaxResponse?

Answer 1

First, the AjaxResponse object has a setData() method not setContent().
To actually subscribe someone to mailchimp through the Drupal module you can use the mailchimp_subscribe() function in the main mailchimp module.

Answer 2

My "working" solution now is:
alter the form block, add an ajax callback function, prevent click and adds some ajax progress visualization.
/**
* Implements hook_form_FORM_ID_alter()
*
* #param \Drupal\mailchimp_signup\Form\MailchimpSignupPageForm $form
* #param \Drupal\Core\Form\FormStateInterface $form_state
* #param $form_id
*/
function mailchimp_ajax_form_form_alter(&$form, \Drupal\Core\Form\FormStateInterface &$form_state, $form_id) {
if ($form_id != 'mailchimp_signup_subscribe_block_form') {
return;
}
$form['submit']['#ajax'] = [
'callback' => 'mailchimp_ajax_form_callback',
'prevent' => 'click',
'progress' => array(
'type' => 'throbber',
'message' => t('Submitting data...')
)
];
}
This is the Ajax Callback:
I create a new AjaxResponse Object and an array of the Drupal messages via drupal_get_messages(). Then some kind of hack to get the right message.
and add an ReplaceCommandObject which replaces the form with the Mailchimp message.
function mailchimp_ajax_form_callback(array &$form, \Drupal\Core\Form\FormStateInterface $form_state) {
$response = new \Drupal\Core\Ajax\AjaxResponse();
$messages = drupal_get_messages();
$message = $messages['status'][0];
if(!$message){
$message = $messages['warning'][0];
}
$response->addCommand(new \Drupal\Core\Ajax\ReplaceCommand('#mailchimp-signup-subscribe-block-form', $message));
return $response;
}
I think there are much more elegant ways to get this.
I still don't know why the submitForm Method of The Mailchimp Form is still invoked...

Answer 3

The AJAX option is committed to the module, you can find it here: https://www.drupal.org/project/mailchimp/issues/2721249
After applying the patch or using the version that includes it, you'll find a checkbox in the form configuration to enable the AJAX in it.