Add preview button display on unpublished nodes

modules/next/css/next.site_preview.iframe.css

@@ -33,7 +33,7 @@
   color: #325e1c;
 }
 
-.next-site-preview-toolbar .operations .live-link .button {
+.next-site-preview-toolbar .operations .live-link .preview-link .button {
   margin-top: 0;
   margin-bottom: 0;
 }

modules/next/next.install

@@ -58,7 +58,6 @@ function next_update_9103() {
   }
 }
 
-
 /**
  * Add the revalidator, revalidate_page and revalidate_paths to next_entity_type_config.
  */

modules/next/next.links.task.yml

@@ -18,3 +18,9 @@ next.settings:
   route_name: next.settings
   base_route: next.settings
   weight: 20
+
+entity.node.headless_preview:
+  title: Preview
+  route_name: entity.node.headless_preview
+  base_route: entity.node.canonical
+  weight: 5

modules/next/next.routing.yml

@@ -26,3 +26,18 @@ next.validate_preview_url:
   requirements:
     _access: 'TRUE'
     _format: 'json'
+
+entity.node.headless_preview:
+  path: '/node/{node}/site-preview'
+  defaults:
+    _title_callback: '\Drupal\next\Controller\SitePreviewController::nodePreviewTitle'
+    _controller: '\Drupal\next\Controller\SitePreviewController::nodePreview'
+  requirements:
+    _entity_access: node.view
+    _module_dependencies: content_moderation
+  options:
+    _node_operation_route: TRUE
+    _admin_route: TRUE
+    parameters:
+      node:
+        type: entity:node

modules/next/src/Controller/SitePreviewController.php

@@ -0,0 +1,101 @@
+<?php
+
+namespace Drupal\next\Controller;
+
+use Drupal\Core\Controller\ControllerBase;
+use Drupal\next\NextEntityTypeManager;
+use Drupal\next\Plugin\SitePreviewerManagerInterface;
+use Drupal\node\Entity\Node;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Defines a controller for the site preview of a node.
+ *
+ * @internal
+ *   This is an internal part of Acquia CMS Headless and may be changed or
+ *   removed at any time without warning. External code should not extend or
+ *   use this class in any way!
+ */
+class SitePreviewController extends ControllerBase {
+  /**
+   * The next entity type manager.
+   *
+   * @var \Drupal\next\NextEntityTypeManager
+   */
+  protected $nextEntityTypeManager;
+
+  /**
+   * The site previewer manager.
+   *
+   * @var \Drupal\next\Plugin\SitePreviewerManagerInterface
+   */
+  protected $sitePreviewerManager;
+
+  /**
+   *
+   */
+  public function __construct(NextEntityTypeManager $nextEntityTypeManager, SitePreviewerManagerInterface $sitePreviewerManager) {
+    $this->nextEntityTypeManager = $nextEntityTypeManager;
+    $this->sitePreviewerManager = $sitePreviewerManager;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+    $container->get('next.entity_type.manager'),
+    $container->get('plugin.manager.next.site_previewer')
+    );
+  }
+
+  /**
+   * Displays the node title for preview.
+   *
+   * @param \Drupal\node\Entity\Node $node
+   *   [description].
+   *
+   * @return string       [description].
+   */
+  public function nodePreviewTitle(Node $node) {
+    return 'Preview: ' . $node->getTitle();
+  }
+
+  /**
+   * Displays the next.js site preview of a node.
+   */
+  public function nodePreview(Node $node) {
+    $storage = \Drupal::entityTypeManager()->getStorage($node->getEntityTypeId());
+    $revision = $storage->loadRevision($storage->getLatestRevisionId($node->id()));
+
+    $next_entity_type_config = $this->nextEntityTypeManager->getConfigForEntityType($revision->getEntityTypeId(), $revision->bundle());
+    $sites = $next_entity_type_config->getSiteResolver()->getSitesForEntity($revision);
+    if (!count($sites)) {
+      throw new \Exception('Next.js sites for the entity could not be resolved.');
+    }
+
+    $config = $this->config('next.settings');
+    $site_previewer_id = $config->get('site_previewer') ?? 'iframe';
+
+    /** @var \Drupal\next\Plugin\SitePreviewerInterface $site_previewer */
+    $site_previewer = $this->sitePreviewerManager->createInstance($site_previewer_id, $config->get('site_previewer_configuration') ?? []);
+    if (!$site_previewer) {
+      throw new PluginNotFoundException('Invalid site previewer.');
+    }
+
+    // Build preview.
+    $preview = $site_previewer->render($revision, $sites);
+
+    $context = [
+      'plugin' => $site_previewer,
+      'entity' => $revision,
+      'sites' => $sites,
+    ];
+
+    // Allow modules to alter the preview.
+    $this->moduleHandler()->alter('next_site_preview', $preview, $context);
+
+    return $preview;
+  }
+
+}