ISTWCMS-5500: adding alternate link to listing pages

uw_fdsu_theme_resp.theme

@@ -35,10 +35,15 @@ function uw_fdsu_theme_resp_preprocess_html(&$variables) {
   $variables['attributes']['class'][] = theme_get_setting('wcms_colour_scheme', 'uw_fdsu_theme_resp') ? theme_get_setting('wcms_colour_scheme', 'uw_fdsu_theme_resp') : 'org-default';
   $variables['uw_admin_page'] = \Drupal::service('uw_cfg_common.uw_analytics')->administrationPage();
 
+  // Add the fav icons.
   _uw_fdsu_theme_resp_add_favicons($variables);
 
+  // Get the route name.
   $route_name = \Drupal::routeMatch()->getRouteName();
+
+  // Perform actions based on the route.
   switch ($route_name) {
+
     // Add Javascript only on the user login page.
     case 'user.login':
       $variables['#attached']['library'][] = 'uw_fdsu_theme_resp/user.login';
@@ -50,12 +55,51 @@ function uw_fdsu_theme_resp_preprocess_html(&$variables) {
       $variables['head_title']['title'] = t('Reference author:') . ' ' . $variables['head_title']['title'];
       break;
 
-    // Teh header/page title on keywords listing page browser
+    // The header/page title on keywords listing page browser
     // tab shows "Reference keyword: " in front of the keyword.
     case 'entity.bibcite_keyword.canonical':
       $variables['head_title']['title'] = t('Reference keyword:') . ' ' . $variables['head_title']['title'];
       break;
 
+    // Adding the alternate link to listing pages.
+    case 'view.uw_view_blogs.blog_page':
+    case 'view.uw_view_events.event_page':
+    case 'view.uw_view_news_items.news_page':
+
+      // Get the parameters from the URL.
+      $parameters = \Drupal::request()->query->all();
+
+      // Get the alternate link based on the route.
+      switch ($route_name) {
+
+        case 'view.uw_view_blogs.blog_page':
+          $link = _uw_fdsu_theme_resp_get_alternate_link(
+            'uw_view_blogs',
+            'uw_public_blog_feed',
+            'Blogs feed'
+          );
+          break;
+
+        case 'view.uw_view_events.event_page':
+          $link = _uw_fdsu_theme_resp_get_alternate_link(
+            'uw_view_events',
+            'uw_public_event_feed',
+            'Events feed'
+          );
+          break;
+
+        case 'view.uw_view_news_items.news_page':
+          $link = _uw_fdsu_theme_resp_get_alternate_link(
+            'uw_view_news_items',
+            'uw_public_news_feed',
+            'News feed'
+          );
+          break;
+      }
+
+      // Add the alternate link to the page.
+      $variables['#attached']['html_head_link'][] = $link;
+      break;
   }
 
   // Get the current path.
@@ -72,6 +116,37 @@ function uw_fdsu_theme_resp_preprocess_html(&$variables) {
   }
 }
 
+/**
+ * Function to get the alternate link.
+ *
+ * @param string $view_machine_name
+ *   The machine name of the view.
+ * @param string $view_display_name
+ *   The display name of the view.
+ * @param string $title
+ *   The title of the alternate link.
+ */
+function _uw_fdsu_theme_resp_get_alternate_link(
+  string $view_machine_name,
+  string $view_display_name,
+  string $title
+) {
+
+  // Get the URL to RSS feed.
+  $url = Url::fromRoute('view.' . $view_machine_name . '.' . $view_display_name);
+  $url->setOptions(['query' => \Drupal::request()->query->all()]);
+
+  // Return the link for the alternate.
+  return [
+    [
+      'rel' => 'alternate',
+      'href' => $url->toString(),
+      'title' => $title,
+      'type' => 'application/rss+xml',
+    ]
+  ];
+}
+
 /**
  * Implements hook_preprocess_responsive_image().
  */