/**
* Builds the backend-specific configuration form.
*
* @param \Drupal\search_api\ServerInterface $server
* The server that is being created or edited.
*/
public function buildBackendConfigForm(array &$form, FormStateInterface $form_state, ServerInterface $server)
{
$form['backend_config'] = array('#type' => 'container', '#attributes' => array('id' => 'search-api-backend-config-form'), '#tree' => TRUE);
if ($server->hasValidBackend()) {
$backend = $server->getBackend();
if ($backend_form = $backend->buildConfigurationForm(array(), $form_state)) {
// If the backend plugin changed, notify the user.
if (!empty($form_state->getValues()['backend'])) {
drupal_set_message($this->t('Please configure the used backend.'), 'warning');
}
// Modify the backend plugin configuration container element.
$form['backend_config']['#type'] = 'details';
$form['backend_config']['#title'] = $this->t('Configure %plugin backend', array('%plugin' => $backend->label()));
$form['backend_config']['#description'] = $backend->getDescription();
$form['backend_config']['#open'] = TRUE;
// Attach the backend plugin configuration form.
$form['backend_config'] += $backend_form;
}
} elseif (!$server->isNew()) {
drupal_set_message($this->t('The backend plugin is missing or invalid.'), 'error');
}
}