Drupal 8.0.0 beta 12. More info: https://www.drupal.org/node/2514176

core/modules/contact/src/MessageViewBuilder.php

@@ -0,0 +1,75 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\contact\MessageViewBuilder.
+ */
+
+namespace Drupal\contact;
+
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Entity\EntityViewBuilder;
+use Drupal\Component\Utility\SafeMarkup;
+use Drupal\Core\Mail\MailFormatHelper;
+use Drupal\Core\Render\Element;
+
+/**
+ * Render controller for contact messages.
+ */
+class MessageViewBuilder extends EntityViewBuilder {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getBuildDefaults(EntityInterface $entity, $view_mode, $langcode) {
+    $build = parent::getBuildDefaults($entity, $view_mode, $langcode);
+    // The message fields are individually rendered into email templates, so
+    // the entity has no template itself.
+    unset($build['#theme']);
+    return $build;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildComponents(array &$build, array $entities, array $displays, $view_mode, $langcode = NULL) {
+    parent::buildComponents($build, $entities, $displays, $view_mode, $langcode);
+
+    foreach ($entities as $id => $entity) {
+      // Add the message extra field, if enabled.
+      $display = $displays[$entity->bundle()];
+      if ($entity->getMessage() && $display->getComponent('message')) {
+        $build[$id]['message'] = array(
+          '#type' => 'item',
+          '#title' => t('Message'),
+          '#markup' => SafeMarkup::checkPlain($entity->getMessage()),
+        );
+      }
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function view(EntityInterface $entity, $view_mode = 'full', $langcode = NULL) {
+    $build = parent::view($entity, $view_mode, $langcode);
+
+    if ($view_mode == 'mail') {
+      // Convert field labels into headings.
+      // @todo Improve \Drupal\Core\Mail\MailFormatHelper::htmlToText() to
+      // convert DIVs correctly.
+      foreach (Element::children($build) as $key) {
+        if (isset($build[$key]['#label_display']) && $build[$key]['#label_display'] == 'above') {
+          $build[$key] += array('#prefix' => '');
+          $build[$key]['#prefix'] = $build[$key]['#title'] . ":\n";
+          $build[$key]['#label_display'] = 'hidden';
+        }
+      }
+      $build['#post_render'][] = function ($html, array $elements) {
+        return MailFormatHelper::htmlToText($html);
+      };
+    }
+    return $build;
+  }
+
+}