add optional permissions filter

radicale/app/base.py

@@ -20,11 +20,12 @@ import logging
 import posixpath
 import sys
 import xml.etree.ElementTree as ET
-from typing import Optional
+from typing import Optional, Union
 
 from radicale import (auth, config, hook, httputils, pathutils, rights,
                       storage, types, utils, web, xmlutils)
 from radicale.log import logger
+from radicale.rights import intersect
 
 # HACK: https://github.com/tiran/defusedxml/issues/54
 import defusedxml.ElementTree as DefusedET  # isort:skip
@@ -106,15 +107,19 @@ class Access:
     permissions: str
     _rights: rights.BaseRights
     _parent_permissions: Optional[str]
+    _permissions_filter: Union[str | None] = None
 
-    def __init__(self, rights: rights.BaseRights, user: str, path: str
+    def __init__(self, rights: rights.BaseRights, user: str, path: str, permissions_filter: Union[str | None] = None
                  ) -> None:
         self._rights = rights
         self.user = user
         self.path = path
-        self.parent_path = pathutils.unstrip_path(
-            posixpath.dirname(pathutils.strip_path(path)), True)
+        self.parent_path = pathutils.parent_path(path)
         self.permissions = self._rights.authorization(self.user, self.path)
+        if permissions_filter is not None:
+            self._permissions_filter = permissions_filter
+            permissions_filtered = intersect(self.permissions, permissions_filter)
+            self.permissions = permissions_filtered
         self._parent_permissions = None
 
     @property
@@ -124,6 +129,9 @@ class Access:
         if self._parent_permissions is None:
             self._parent_permissions = self._rights.authorization(
                 self.user, self.parent_path)
+        if self._permissions_filter is not None:
+            parent_permissions_filtered = intersect(self._parent_permissions, self._permissions_filter)
+            self._parent_permissions = parent_permissions_filtered
         return self._parent_permissions
 
     def check(self, permission: str,