Add custom tag to cache entry

src/RemoteMenuParser.php

@@ -5,7 +5,9 @@ declare(strict_types=1);
 namespace Drupal\menu_parser_php;
 
 use Drupal\Component\Datetime\TimeInterface;
+use Drupal\Core\Cache\Cache;
 use Drupal\Core\Cache\CacheBackendInterface;
+use Drupal\Core\Cache\RefinableCacheableDependencyInterface;
 use Drupal\Core\Config\Config;
 use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Menu\MenuLinkTreeElement;
@@ -64,13 +66,22 @@ class RemoteMenuParser {
    *
    * @param string $url
    *   The URL at which the JSON linkset is available.
+   * @param \Drupal\Core\Cache\RefinableCacheableDependencyInterface|null $metadata
+   *   Optional cache metadata.
    *
    * @return \Drupal\Core\Menu\MenuLinkTreeElement[]|null
    *   A tree of MenuLinkTreeElement objects. NULL on failure.
    */
-  public function readRemoteMenu(string $url): ?array {
+  public function readRemoteMenu(string $url, RefinableCacheableDependencyInterface $metadata = NULL): ?array {
     $cached = $this->cacheBin->get($url);
     if ($cached) {
+      if ($metadata) {
+        $tags = $cached->tags ?? [];
+        $expire = $cached->expire ?? Cache::PERMANENT;
+        $metadata->addCacheTags($tags);
+        $max_age = $expire - $this->time->getCurrentTime();
+        $metadata->mergeCacheMaxAge($max_age);
+      }
       return $cached->data;
     }
 
@@ -100,7 +111,12 @@ class RemoteMenuParser {
     else {
       $expire = $this->time->getCurrentTime() + $expire_time_config;
     }
-    $this->cacheBin->set($url, $data, $expire);
+    $cache_tags = [static::getCacheTag($url)];
+    $this->cacheBin->set($url, $data, $expire, $cache_tags);
+    if ($metadata) {
+      $metadata->mergeCacheMaxAge($expire_time_config);
+      $metadata->addCacheTags($cache_tags);
+    }
     return $data;
   }
 
@@ -186,4 +202,18 @@ class RemoteMenuParser {
     return '.' . implode('.', $hierarchy_array);
   }
 
+  /**
+   * Generates a custom cache tag for a remote menu URL.
+   *
+   * @param string $url
+   *   The URL.
+   *
+   * @return string
+   *   The cache tag name.
+   */
+  public static function getCacheTag(string $url): string {
+    $hash = substr(hash('sha256', $url), 30);
+    return 'menu_parser_php:menu:' . $hash;
+  }
+
 }