Refactor models' .by_id().

[plomtask] / plomtask / db.py

diff --git a/plomtask/db.py b/plomtask/db.py
index 2cc1d64d54576a46a0b9c7edb513abaa28d4008e..abd8f6181db946b357902a0ec851f51919f37344 100644 (file)
--- a/plomtask/db.py
+++ b/plomtask/db.py
@@ -76,7 +76,8 @@ class BaseModel:
     id_type: type[Any] = int
 
     @classmethod
-    def from_table_row(cls, db_conn: DatabaseConnection, row: Row) -> Any:
+    def from_table_row(cls, db_conn: DatabaseConnection,
+                       row: Row | list[Any]) -> Any:
         """Make from DB row, write to DB cache."""
         obj = cls(*row)
         assert isinstance(obj.id_, cls.id_type)
@@ -84,6 +85,25 @@ class BaseModel:
         cache[obj.id_] = obj
         return obj
 
+    @classmethod
+    def _by_id(cls,
+               db_conn: DatabaseConnection,
+               id_: int | str) -> tuple[Any, bool]:
+        """Return instance found by ID, or None, and if from cache or not."""
+        from_cache = False
+        obj = None
+        cache = getattr(db_conn, f'cached_{cls.table_name}')
+        if id_ in cache.keys():
+            obj = cache[id_]
+            from_cache = True
+        else:
+            for row in db_conn.exec(f'SELECT * FROM {cls.table_name} '
+                                    'WHERE id = ?', (id_,)):
+                obj = cls.from_table_row(db_conn, row)
+                cache[id_] = obj
+                break
+        return obj, from_cache
+
     def set_int_id(self, id_: int | None) -> None:
         """Set id_ if >= 1 or None, else fail."""
         if (id_ is not None) and id_ < 1: