Added helpers

sqlorm/engine.py

@@ -4,7 +4,6 @@
 import logging
 import inspect
 import urllib.parse
-import functools
 from blinker import Namespace
 from .sql import render, ParametrizedStmt
 from .resultset import ResultSet, CompositeResultSet, CompositionMap
@@ -579,21 +578,3 @@ def _signal_rv(signal_rv):
         if rv:
             final_rv = rv
     return final_rv
-
-
-def connect_via_engine(engine, signal, func=None):
-    def decorator(func):
-        @functools.wraps(func)
-        def wrapper(sender, **kw):
-            matches = False
-            if isinstance(sender, Engine):
-                matches = sender is engine
-            elif isinstance(sender, Session):
-                matches = sender.engine is engine
-            elif isinstance(sender, Transaction):
-                matches = sender.session.engine is engine
-            if matches:
-                return func(sender, **kw)
-        signal.connect(wrapper, weak=False)
-        return wrapper
-    return decorator(func) if func else decorator

sqlorm/helpers.py

@@ -0,0 +1,32 @@
+from .engine import Engine, Session, Transaction, ensure_session
+import functools
+
+
+def connect_via_engine(engine, signal, func=None):
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(sender, **kw):
+            matches = False
+            if isinstance(sender, Engine):
+                matches = sender is engine
+            elif isinstance(sender, Session):
+                matches = sender.engine is engine
+            elif isinstance(sender, Transaction):
+                matches = sender.session.engine is engine
+            if matches:
+                return func(sender, **kw)
+        signal.connect(wrapper, weak=False)
+        return wrapper
+    return decorator(func) if func else decorator
+
+
+def after_commit(func, *args, **kwargs):
+    with ensure_session() as session:
+        def rollback_listener(session):
+            Session.after_commit.disconnect(commit_listener)
+            Session.after_rollback.disconnect(rollback_listener)
+        def commit_listener(session):
+            func(*args, **kwargs)
+            rollback_listener(session)
+        Session.after_commit.connect(commit_listener, session, weak=False)
+        Session.after_rollback.connect(rollback_listener, session, weak=False)