Minor change to service.

crudkit/core/service.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from collections.abc import Iterable
+from flask import current_app
 from typing import Any, Callable, Type, TypeVar, Generic, Optional, Protocol, runtime_checkable, cast
 from sqlalchemy import and_, func, inspect, or_, text
 from sqlalchemy.engine import Engine, Connection
@@ -133,25 +134,26 @@ class CRUDService(Generic[T]):
         self.polymorphic = polymorphic
         self.supports_soft_delete = hasattr(model, 'is_deleted')
 
-        # Derive engine WITHOUT leaking a session/connection
+        self._backend: Optional[BackendInfo] = backend
-        bind = getattr(session_factory, "bind", None)
-        if bind is None:
-            tmp_sess = session_factory()
-            try:
-                bind = tmp_sess.get_bind()
-            finally:
-                try:
-                    tmp_sess.close()
-                except Exception:
-                    pass
-
-        eng: Engine = bind.engine if isinstance(bind, Connection) else cast(Engine, bind)
-        self.backend = backend or make_backend_info(eng)
 
     @property
     def session(self) -> Session:
+        """Always return the Flask-scoped Session if available; otherwise the provided factory."""
+        try:
+            sess = current_app.extensions["crudkit"]["Session"]
+            return sess
+        except Exception:
             return self._session_factory()
 
+    @property
+    def backend(self) -> BackendInfo:
+        """Resolve backend info lazily against the active session's engine."""
+        if self._backend is None:
+            bind = self.session.get_bind()
+            eng: Engine = bind.engine if isinstance(bind, Connection) else cast(Engine, bind)
+            self._backend = make_backend_info(eng)
+        return self._backend
+
     def get_query(self):
         if self.polymorphic:
             poly = with_polymorphic(self.model, "*")