--- /dev/null
+<?php
+
+namespace Drupal\Core\Cache\Context;
+
+use Drupal\Core\Cache\CacheableMetadata;
+
+/**
+ * Defines a cache context service for path parents.
+ *
+ * Cache context ID: 'url.path.parent'.
+ *
+ * This allows for caching based on the path, excluding everything after the
+ * last forward slash.
+ */
+class PathParentCacheContext extends RequestStackCacheContextBase implements CacheContextInterface {
+
+ /**
+ * {@inheritdoc}
+ */
+ public static function getLabel() {
+ return t('Parent path');
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getContext() {
+ $request = $this->requestStack->getCurrentRequest();
+ $path_elements = explode('/', trim($request->getPathInfo(), '/'));
+ array_pop($path_elements);
+ return implode('/', $path_elements);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getCacheableMetadata() {
+ return new CacheableMetadata();
+ }
+
+}