Added automatic expiration of proxy dicts, updated sqlalchemy in requirements

CHANGES.rst

@@ -4,6 +4,13 @@ Changelog
 Here you can see the full list of changes between each SQLAlchemy-Utils release.
 
 
+0.12.2 (2013-05-29)
+^^^^^^^^^^^^^^^^^^^
+
+- Added automatic expiration of proxy dicts
+
+
+
 0.12.1 (2013-05-18)
 ^^^^^^^^^^^^^^^^^^^
 

setup.py

@@ -24,7 +24,7 @@ class PyTest(Command):
 
 setup(
     name='SQLAlchemy-Utils',
-    version='0.12.1',
+    version='0.12.2',
     url='https://github.com/kvesteri/sqlalchemy-utils',
     license='BSD',
     author='Konsta Vesterinen',
@@ -38,7 +38,7 @@ setup(
     include_package_data=True,
     platforms='any',
     install_requires=[
-        'SQLAlchemy>=0.7.8',
+        'SQLAlchemy>=0.8.0',
         'phonenumbers>=5.4b1',
         'colour==0.0.2'
     ],

sqlalchemy_utils/__init__.py

@@ -1,7 +1,7 @@
-from .functions import sort_query, defer_except, escape_like
+from .functions import sort_query, defer_except, escape_like, primary_keys
 from .listeners import coercion_listener
 from .merge import merge, Merger
-from .proxy_dict import ProxyDict
+from .proxy_dict import ProxyDict, proxy_dict
 from .types import (
     ColorType,
     EmailType,
@@ -25,6 +25,8 @@ __all__ = (
     escape_like,
     instrumented_list,
     merge,
+    primary_keys,
+    proxy_dict,
     ColorType,
     EmailType,
     InstrumentedList,

sqlalchemy_utils/proxy_dict.py

@@ -2,11 +2,11 @@ import sqlalchemy as sa
 
 
 class ProxyDict(object):
-    def __init__(self, parent, collection_name, child_class, key_name):
+    def __init__(self, parent, collection_name, mapping_attr):
         self.parent = parent
         self.collection_name = collection_name
-        self.child_class = child_class
-        self.key_name = key_name
+        self.child_class = mapping_attr.class_
+        self.key_name = mapping_attr.key
         self.cache = {}
 
     @property
@@ -26,20 +26,22 @@ class ProxyDict(object):
     def fetch(self, key):
         return self.collection.filter_by(**{self.key_name: key}).first()
 
+    def create_new_instance(self, key):
+        value = self.child_class(**{self.key_name: key})
+        self.collection.append(value)
+        return value
+
     def __getitem__(self, key):
         if key in self.cache:
             return self.cache[key]
 
         session = sa.orm.object_session(self.parent)
         if not session or not sa.orm.util.has_identity(self.parent):
-            value = self.child_class(**{self.key_name: key})
-            self.collection.append(value)
+            value = self.create_new_instance(key)
         else:
             value = self.fetch(key)
             if not value:
-                value = self.child_class(**{self.key_name: key})
-                self.collection.append(value)
-
+                value = self.create_new_instance(key)
         self.cache[key] = value
         return value
 
@@ -51,3 +53,24 @@ class ProxyDict(object):
             pass
         self.collection.append(value)
         self.cache[key] = value
+
+
+def proxy_dict(parent, collection_name, mapping_attr):
+    try:
+        parent._proxy_dicts
+    except AttributeError:
+        def expire_proxy_dicts(target, context):
+            target._proxy_dicts = {}
+
+        sa.event.listen(parent.__class__, 'expire', expire_proxy_dicts)
+        parent._proxy_dicts = {}
+
+    try:
+        return parent._proxy_dicts[collection_name]
+    except KeyError:
+        parent._proxy_dicts[collection_name] = ProxyDict(
+            parent,
+            collection_name,
+            mapping_attr
+        )
+    return parent._proxy_dicts[collection_name]

tests/test_proxy_dict.py

@@ -1,6 +1,6 @@
 from flexmock import flexmock
 import sqlalchemy as sa
-from sqlalchemy_utils import ProxyDict
+from sqlalchemy_utils import ProxyDict, proxy_dict
 from tests import TestCase
 
 
@@ -21,16 +21,11 @@ class TestProxyDict(TestCase):
 
             @property
             def translations(self):
-                try:
-                    return self.proxied_translations
-                except AttributeError:
-                    self.proxied_translations = ProxyDict(
-                        self,
-                        '_translations',
-                        ArticleTranslation,
-                        'locale'
-                    )
-                return self.proxied_translations
+                return proxy_dict(
+                    self,
+                    '_translations',
+                    ArticleTranslation.locale
+                )
 
         class ArticleTranslation(self.Base):
             __tablename__ = 'article_translation'
@@ -83,3 +78,16 @@ class TestProxyDict(TestCase):
             name=u'something'
         )
         article.translations['en']
+
+    def test_committing_session_empties_proxy_dict_cache(self):
+        article = self.Article()
+        (
+            flexmock(ProxyDict)
+            .should_receive('fetch')
+            .twice()
+        )
+        self.session.add(article)
+        self.session.commit()
+        article.translations['en']
+        self.session.commit()
+        article.translations['en']