core: optionally don't return groups' users and users' groups by default (#9179)

* core: don't return groups' users and users' groups by default

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

* explicitly fetch users and groups in LDAP

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

* add indicies

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

---------

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

authentik/core/api/groups.py

@@ -5,10 +5,15 @@ from json import loads
 from django.http import Http404
 from django_filters.filters import CharFilter, ModelMultipleChoiceFilter
 from django_filters.filterset import FilterSet
-from drf_spectacular.utils import OpenApiResponse, extend_schema
+from drf_spectacular.utils import (
+    OpenApiParameter,
+    OpenApiResponse,
+    extend_schema,
+    extend_schema_field,
+)
 from guardian.shortcuts import get_objects_for_user
 from rest_framework.decorators import action
-from rest_framework.fields import CharField, IntegerField
+from rest_framework.fields import CharField, IntegerField, SerializerMethodField
 from rest_framework.request import Request
 from rest_framework.response import Response
 from rest_framework.serializers import ListSerializer, ModelSerializer, ValidationError
@@ -45,9 +50,7 @@ class GroupSerializer(ModelSerializer):
     """Group Serializer"""
 
     attributes = JSONDictField(required=False)
-    users_obj = ListSerializer(
-        child=GroupMemberSerializer(), read_only=True, source="users", required=False
-    )
+    users_obj = SerializerMethodField()
     roles_obj = ListSerializer(
         child=RoleSerializer(),
         read_only=True,
@@ -58,6 +61,19 @@ class GroupSerializer(ModelSerializer):
 
     num_pk = IntegerField(read_only=True)
 
+    @property
+    def _should_include_users(self) -> bool:
+        request: Request = self.context.get("request", None)
+        if not request:
+            return True
+        return str(request.query_params.get("include_users", "true")).lower() == "true"
+
+    @extend_schema_field(GroupMemberSerializer(many=True))
+    def get_users_obj(self, instance: Group) -> list[GroupMemberSerializer] | None:
+        if not self._should_include_users:
+            return None
+        return GroupMemberSerializer(instance.users, many=True).data
+
     def validate_parent(self, parent: Group | None):
         """Validate group parent (if set), ensuring the parent isn't itself"""
         if not self.instance or not parent:
@@ -145,6 +161,14 @@ class GroupViewSet(UsedByMixin, ModelViewSet):
     filterset_class = GroupFilter
     ordering = ["name"]
 
+    @extend_schema(
+        parameters=[
+            OpenApiParameter("include_users", bool, default=True),
+        ]
+    )
+    def list(self, request, *args, **kwargs):
+        return super().list(request, *args, **kwargs)
+
     @permission_required(None, ["authentik_core.add_user"])
     @extend_schema(
         request=UserAccountSerializer,