Fix case where sqlachemy db driver raises exception (#69)

If query a numeric column with a string value, some drivers (pyscopg) will throw
a DataError. This is similar fix to mongo, peewee, pony datastores.

flask_security/datastore.py

@@ -241,24 +241,33 @@ def __init__(self, db, user_model, role_model):
 
     def get_user(self, identifier):
         from sqlalchemy import func as alchemyFn
+        from sqlalchemy.exc import DataError
+
         user_model_query = self.user_model.query
         if hasattr(self.user_model, 'roles'):
             from sqlalchemy.orm import joinedload
             user_model_query = user_model_query.options(joinedload('roles'))
 
-        rv = self.user_model.query.get(identifier)
-        if rv is not None:
-            return rv
+        try:
+            rv = user_model_query.get(identifier)
+            if rv is not None:
+                return rv
+        except DataError:
+            # This can happen if trying a string against a numeric column
+            pass
 
         # Not PK - iterate through other attributes and look for 'identifier'
         for attr in get_identity_attributes():
             # Look for exact case-insensitive match - 'ilike' honors wild cards
             # which isn't what we want.
             query = alchemyFn.lower(getattr(self.user_model, attr)) \
                 == alchemyFn.lower(identifier)
-            rv = user_model_query.filter(query).first()
-            if rv is not None:
-                return rv
+            try:
+                rv = user_model_query.filter(query).first()
+                if rv is not None:
+                    return rv
+            except DataError:
+                pass
 
     def find_user(self, **kwargs):
         query = self.user_model.query

tests/test_datastore.py

@@ -6,11 +6,13 @@
     Datastore tests
 """
 
+from mock import MagicMock, patch
 from pytest import raises
 from utils import init_app_with_options, get_num_queries, is_sqlalchemy
 
 from flask_security import RoleMixin, Security, UserMixin
-from flask_security.datastore import Datastore, UserDatastore
+from flask_security.datastore import Datastore, UserDatastore, \
+    SQLAlchemyUserDatastore
 
 
 class User(UserMixin):
@@ -108,6 +110,26 @@ def test_get_user(app, datastore):
         assert user is not None
 
 
+def test_get_user_raise(app, sqlalchemy_datastore):
+    """
+    Some drivers will raise exceptions if we attempt to query a
+    numeric column with a string value
+    """
+    from sqlalchemy.exc import DataError
+    init_app_with_options(app, sqlalchemy_datastore)
+
+    mock_query = MagicMock(name='querymock')
+    mock_query.options.return_value = mock_query
+    mock_query.filter.return_value.first.return_value = None
+    mock_query.get.side_effect = DataError('stmt', 'params',
+                                           SQLAlchemyUserDatastore)
+    with patch.object(sqlalchemy_datastore.user_model, 'query', mock_query):
+        with app.app_context():
+            user = sqlalchemy_datastore.get_user('1')
+            # this should be none (and not raise an exception)
+            assert user is None
+
+
 def test_find_user(app, datastore):
     init_app_with_options(app, datastore)