group: add general support and for htgroup file

radicale/group/__init__.py

@@ -0,0 +1,71 @@
+# This file is part of Radicale - CalDAV and CardDAV server
+# Copyright © 2026-2026 Peter Bieringer <pb@bieringer.de>
+#
+# This library is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Radicale.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+Group membership module.
+
+Enrich user with group membership
+
+Take a look at the class ``BaseGroup`` if you want to implement your own.
+
+"""
+
+from typing import Sequence, Set, final
+
+from radicale import config, utils
+from radicale.log import logger
+
+INTERNAL_TYPES: Sequence[str] = ("none",
+                                 "htgroup",
+                                 )
+
+
+def load(configuration: "config.Configuration") -> "BaseGroup":
+    """Load the group module chosen in configuration."""
+    _type = configuration.get("group", "type")
+    if _type == "none":
+        logger.info("No user groups lookup method is selected")
+    else:
+        logger.info("User groups lookup method: %r", _type)
+    return utils.load_plugin(INTERNAL_TYPES, "group", "Group", BaseGroup,
+                             configuration)
+
+
+class BaseGroup:
+
+    def __init__(self, configuration: "config.Configuration") -> None:
+        """Initialize BaseGroup.
+
+        ``configuration`` see ``radicale.config`` module.
+        The ``configuration`` must not change during the lifetime of
+        this object, it is kept as an internal reference.
+
+        """
+        self.configuration = configuration
+        self._type = configuration.get("group", "type")
+
+    def _groups(self, login: str) -> Set[str]:
+        """Retrieve set of groups of a user
+
+        ``login`` the login name
+
+        """
+
+        raise NotImplementedError
+
+    @final
+    def groups(self, login: str) -> Set[str]:
+        return self._groups(login)