diff --git a/api/ovdashboard_api/__init__.py b/api/ovdashboard_api/__init__.py
index 4fa6c6e..2baa131 100644
--- a/api/ovdashboard_api/__init__.py
+++ b/api/ovdashboard_api/__init__.py
@@ -1,8 +1,10 @@
 import asyncio
 import functools
+import time
 from typing import Any
 
 import caldav
+from async_lru import alru_cache
 from webdav3 import client as WebDAVclient
 
 from .config import SETTINGS
@@ -31,6 +33,28 @@ def run_in_executor(f):
     return inner
 
 
+def get_ttl_hash(seconds: int = 20) -> int:
+    """
+    Return the same value within `seconds` time period
+    https://stackoverflow.com/a/55900800
+    """
+    return round(time.time() / seconds)
+
+
+def timed_alru_cache(**decorator_kwargs):
+    def decorate(f):
+        @alru_cache(**decorator_kwargs)
+        @functools.wraps(f)
+        async def wrapper(ttl_hash: int, *args, **kwargs):
+            del ttl_hash
+
+            return await f(*args, **kwargs)
+
+        return wrapper
+
+    return decorate
+
+
 @functools.lru_cache
 def webdav_resource(remote_path: Any) -> WebDAVclient.Resource:
     return _WEBDAV_CLIENT.resource(remote_path)
diff --git a/api/ovdashboard_api/dav_file.py b/api/ovdashboard_api/dav_file.py
index c774a15..c6f9902 100644
--- a/api/ovdashboard_api/dav_file.py
+++ b/api/ovdashboard_api/dav_file.py
@@ -1,32 +1,19 @@
 import logging
-import time
 from dataclasses import dataclass
 from io import BytesIO
-from typing import Any, Optional
+from typing import Any
 
-from async_lru import alru_cache
 from webdav3.client import Resource
 
-from . import run_in_executor, webdav_resource
+from . import get_ttl_hash, run_in_executor, timed_alru_cache, webdav_resource
 
 _logger = logging.getLogger(__name__)
 
 
-def _get_ttl_hash(seconds: int = 20) -> int:
-    """
-    Return the same value within `seconds` time period
-    https://stackoverflow.com/a/55900800
-    """
-    return round(time.time() / seconds)
-
-
-@alru_cache(maxsize=20)
+@timed_alru_cache(maxsize=20)
 async def _get_buffer(
     remote_path: Any,
-    ttl_hash: Optional[int] = None,
 ) -> BytesIO:
-    del ttl_hash
-
     @run_in_executor
     def buffer_inner(resource: Resource) -> BytesIO:
         _logger.info(f"updating {resource}")
@@ -46,8 +33,8 @@ class DavFile:
     @property
     async def __buffer(self) -> BytesIO:
         return await _get_buffer(
+            ttl_hash=get_ttl_hash(),
             remote_path=self.remote_path,
-            ttl_hash=_get_ttl_hash(20),
         )
 
     @property