Snippets

Ajax form element callback

Sign up to bookmark this snippet
Components

To save the API token field without submitting the form, you can add a simple ajax callback function. In this example, we are saving the field value on the keyup event.

use Drupal\Core\Ajax\AjaxResponse;
use Drupal\Core\Form\FormStateInterface;

public function buildForm(array $form, FormStateInterface $form_state) {
  $form['api_token'] = [
    '#type' => 'textfield',
    '#title' => $this->t('API token'),
    '#ajax' => [
      'callback' => '::updateApiToken',
      'event' => 'keyup',
    ],
  ];

  return parent::buildForm($form, $form_state);
}

public function updateApiToken(array $form, FormStateInterface $form_state) {
  $response = new AjaxResponse();
  $this->config('my_module.settings')
    ->set('api_token', $form_state->getValue('api_token'))
    ->save();
  return $response;
}

Remove an item from entity reference field

Sign up to bookmark this snippet
Components

Let's say that you have a multivalue reference field named field_tags in a node type. To remove a specific item from that field you can do something like this:

$node_id = 152;
$tag_to_remove = 56;
$entity_storage = \Drupal::entityTypeManager()->getStorage('node');
$entity = $entity_storage->load($node_id);

foreach ($entity->get('field_tags') as $delta => $field_item) {
  if ($field_item->target_id == $tag_to_remove) {
    $entity->get('field_tags')->removeItem($delta);
    $entity->save();
    break;
  }
}

Redirect after login

Sign up to bookmark this snippet
Components

Adding a redirect to hook_user_login() is a common mistake. You should never add the redirect there because redirecting users in that hook would stop other hook_user_login() implementations from being invoked. To properly redirect users to some page after they log in, you should add a custom submit handler to the user login form.

use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Url;

/**
 * Implements hook_form_FORM_ID_alter().
 */
function MY_MODULE_form_user_login_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  $form['#submit'][] = 'MY_MODULE_user_login_form_submit';
}

/**
 * Custom submit handler for the login form.
 */
function MY_MODULE_user_login_form_submit($form, FormStateInterface $form_state) {
  $url = Url::fromRoute('<front>');
  $form_state->setRedirectUrl($url);
}