fix: de/serialize ResourceType when caching results

Signed-off-by: Salvatore Martire <4652631+salmart-dev@users.noreply.github.com>

Author: salmart-dev

apps/dav/lib/Paginate/PaginateCache.php

@@ -14,11 +14,14 @@
 use OCP\ICacheFactory;
 use OCP\IDBConnection;
 use OCP\Security\ISecureRandom;
+use Sabre\DAV\Xml\Property\ResourceType;
 
 class PaginateCache {
 	public const TTL = 60 * 60;
 	private const CACHE_COUNT_SUFFIX = 'count';
 
+	private const RESOURCE_TYPE_PROPERTY = '{DAV:}resourcetype';
+
 	private ICache $cache;
 
 	public function __construct(
@@ -40,6 +43,7 @@ public function store(string $uri, \Iterator $items): array {
 
 		$count = 0;
 		foreach ($items as $item) {
+			$this->serializeResourceType($item);
 			// Add small margin to avoid fetching valid count and then expired entries
 			$this->cache->set($cacheKey . $count, $item, self::TTL + 60);
 			++$count;
@@ -61,7 +65,49 @@ public function get(string $uri, string $token, int $offset, int $count): Genera
 
 		$lastItem = min($nbItems, $offset + $count);
 		for ($i = $offset; $i < $lastItem; ++$i) {
-			yield $this->cache->get($cacheKey . $i);
+			$element = $this->cache->get($cacheKey . $i);
+			$this->deserializeResourceType($element);
+			yield $element;
+		}
+	}
+
+	/**
+	 * The ResourceType class is lost when json_encode is used.
+	 * This function serializes it in place so that this does not happen.
+	 *
+	 * @param array $item
+	 * @return void
+	 */
+	private function serializeResourceType(array &$item): void {
+		foreach ($item as &$responseProperties) {
+			if (!is_array($responseProperties)) {
+				continue;
+			}
+			foreach ($responseProperties as &$propertyValue) {
+				if ($propertyValue instanceof ResourceType) {
+					$propertyValue = serialize($propertyValue);
+				}
+			}
+		}
+	}
+
+	/**
+	 * The ResourceType class in the cache is serialized. This function will
+	 * deserialize it in place.
+	 *
+	 * @param array $item
+	 * @return void
+	 */
+	private function deserializeResourceType(array &$item): void {
+		foreach ($item as &$responseProperties) {
+			foreach ($responseProperties as $propertyName => &$propertyValue) {
+				if ($propertyName === self::RESOURCE_TYPE_PROPERTY) {
+					$propertyValue = unserialize(
+						$propertyValue,
+						[ 'allowed_classes' => [ResourceType::class]]
+					);
+				}
+			}
 		}
 	}