MERGED MAGIC-REMOVAL BRANCH TO TRUNK. This change is highly backwards-incompatible. Please read http://code.djangoproject.com/wiki/RemovingTheMagic for upgrade instructions.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@2809 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/middleware/transaction.py

@@ -0,0 +1,28 @@
+from django.conf import settings
+from django.db import transaction
+
+class TransactionMiddleware:
+    """
+    Transaction middleware. If this is enabled, each view function will be run
+    with commit_on_response activated - that way a save() doesn't do a direct
+    commit, the commit is done when a successful response is created. If an
+    exception happens, the database is rolled back.
+    """
+    def process_request(self, request):
+        """Enters transaction management"""
+        transaction.enter_transaction_management()
+        transaction.managed(True)
+
+    def process_exception(self, request, exception):
+        """Rolls back the database and leaves transaction management"""
+        if transaction.is_dirty():
+            transaction.rollback()
+        transaction.leave_transaction_management()
+
+    def process_response(self, request, response):
+        """Commits and leaves transaction management."""
+        if transaction.is_managed():
+            if transaction.is_dirty():
+                transaction.commit()
+            transaction.leave_transaction_management()
+        return response