Add SEO values to pages

Author: mglaman

user/config/site.yaml

@@ -1,4 +1,4 @@
-title: Drupal Commerce docs
+title: Drupal Commerce documentation
 metadata:
     description: 'Drupal Commerce documentation'
 

user/localhost/config/system.yaml

@@ -3,8 +3,8 @@ assets:
   js_pipeline: false
 
 twig:
-  cache: true
+  cache: false
   debug: true
 
 debugger:
-  enabled: false
+  enabled: true

user/themes/commerce/commerce.php

@@ -1,9 +1,60 @@
 <?php
 namespace Grav\Theme;
 
+use Grav\Common\Page\Page;
 use Grav\Common\Theme;
 
 class Commerce extends Theme
 {
 
+  public static function getSubscribedEvents()
+  {
+    return [
+      'onThemeInitialized' => ['onThemeInitialized', 0]
+    ];
+  }
+
+  public function onThemeInitialized()
+  {
+    if ($this->isAdmin()) {
+      $this->active = false;
+      return;
+    }
+
+    $this->enable([
+      'onPageInitialized' => ['onPageInitialized', 0]
+    ]);
+  }
+
+  /**
+   * Add content after page content was read into the system.
+   *
+   */
+  public function onPageInitialized()
+  {
+    /** @var \Grav\Common\Page\Page $page */
+    $page = $this->grav['page'];
+    $config = $this->mergeConfig($page);
+    $metadata = $page->metadata();
+    $summary = trim(strip_tags($page->summary(null, true)));
+
+    $metadata_values = [
+      'og:sitename' => $config->get('site.title'),
+      'og:title' => $page->title(),
+      'og:description' => $summary,
+      'twitter:card' => 'summary',
+      'twitter:title' => $page->title(),
+      'twitter:description' => $summary,
+      'twitter:site' => '@drupalcommerce',
+      'twitter:label1' => 'Filed under',
+      'twitter:data1' => $page->parent()->title(),
+    ];
+    foreach ($metadata_values as $property => $value) {
+      $metadata[$property]['name'] = $property;
+      $metadata[$property]['property'] = $property;
+      $metadata[$property]['content'] = $value;
+    }
+
+    $page->metadata($metadata);
+  }
 }