OpenID: make nonce creation atomic.

get_or_create() is pointless, non-atomic thing. Instead, just try to
create the nonce and catch IntegrityError.

1 files changed, 8 insertions, 6 deletions

diff --git a/okupy/accounts/openid_store.py b/okupy/accounts/openid_store.py
index 013fcef..5f66abb 100644
--- a/okupy/accounts/openid_store.py
+++ b/okupy/accounts/openid_store.py
@@ -5,6 +5,7 @@ import calendar
 import datetime
 import time
 
+from django.db import IntegrityError
 from django.utils import timezone
 
 from openid.store.interface import OpenIDStore
@@ -78,15 +79,16 @@ class DjangoDBOpenIDStore(OpenIDStore):
         if abs((nonce_dt - timezone.now()).total_seconds()) > nonce.SKEW:
             return False
 
-        objs = db_models.OpenID_Nonce.objects
-        n, created = objs.get_or_create(
+        n = db_models.OpenID_Nonce(
             server_uri=server_uri,
             ts=nonce_dt,
             salt=salt)
-
-        # if it was created, it is unique and everything's fine.
-        # if we found one existing, it is duplicate and we return False.
-        return created
+        try:
+            n.save()
+        except IntegrityError:
+            # non-unique
+            return False
+        return True
 
     def cleanupNonces(self):
         skew_td = datetime.timedelta(seconds=nonce.SKEW)