--- /dev/null
+<?php
+
+/**
+ * @file
+ * Contains custom contact message functionality for ContactStorageTest.
+ */
+
+use Drupal\contact\ContactFormInterface;
+use Drupal\Core\Entity\EntityTypeInterface;
+use Drupal\Core\Field\BaseFieldDefinition;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Implements hook_entity_base_field_info().
+ */
+function contact_storage_test_entity_base_field_info(EntityTypeInterface $entity_type) {
+ if ($entity_type->id() == 'contact_message') {
+ $fields = [];
+
+ $fields['id'] = BaseFieldDefinition::create('integer')
+ ->setLabel(t('Message ID'))
+ ->setDescription(t('The message ID.'))
+ ->setReadOnly(TRUE)
+ ->setSetting('unsigned', TRUE);
+
+ return $fields;
+ }
+}
+
+
+/**
+ * Implements hook_entity_type_alter().
+ */
+function contact_storage_test_entity_type_alter(array &$entity_types) {
+ /** @var $entity_types \Drupal\Core\Entity\EntityTypeInterface[] */
+ // Set the controller class for nodes to an alternate implementation of the
+ // Drupal\Core\Entity\EntityStorageInterface interface.
+ $entity_types['contact_message']->setStorageClass('\Drupal\Core\Entity\Sql\SqlContentEntityStorage');
+ $keys = $entity_types['contact_message']->getKeys();
+ $keys['id'] = 'id';
+ $entity_types['contact_message']->set('entity_keys', $keys);
+ $entity_types['contact_message']->set('base_table', 'contact_message');
+}
+
+/**
+ * Implements hook_form_FORM_ID_alter() for contact_form_form().
+ */
+function contact_storage_test_form_contact_form_form_alter(&$form, FormStateInterface $form_state) {
+ /** @var \Drupal\contact\ContactFormInterface $contact_form */
+ $contact_form = $form_state->getFormObject()->getEntity();
+ $form['send_a_pony'] = [
+ '#type' => 'checkbox',
+ '#title' => t('Send submitters a voucher for a free pony.'),
+ '#description' => t('Enable to send an additional email with a free pony voucher to anyone who submits the form.'),
+ '#default_value' => $contact_form->getThirdPartySetting('contact_storage_test', 'send_a_pony', FALSE),
+ ];
+ $form['#entity_builders'][] = 'contact_storage_test_contact_form_form_builder';
+}
+/**
+ * Entity builder for the contact form edit form with third party options.
+ *
+ * @see contact_storage_test_form_contact_form_edit_form_alter()
+ */
+function contact_storage_test_contact_form_form_builder($entity_type, ContactFormInterface $contact_form, &$form, FormStateInterface $form_state) {
+ $contact_form->setThirdPartySetting('contact_storage_test', 'send_a_pony', $form_state->getValue('send_a_pony'));
+}