--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/soc/models/base.py	Wed Aug 27 21:21:44 2008 +0000
@@ -0,0 +1,84 @@
+#!/usr/bin/python2.5
+#
+# Copyright 2008 the Melange authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+# 
+#   http://www.apache.org/licenses/LICENSE-2.0
+# 
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Module containing enhanced db.Model classes.
+
+The classes in this module are intended to serve as base classes for all
+Melange Datastore Models.
+"""
+
+__authors__ = [
+  '"Todd Larsen" <tlarsen@google.com>',
+]
+
+
+from google.appengine.ext import db
+
+from soc.views.helpers import forms_helpers
+
+
+class ModelWithFieldAttributes(db.Model):
+  """A db.Model extension that provides access to Model properties attributes.
+  
+  Due to the way the Property class in Google App Engine implements __get__()
+  and __set__(), it is not possible to access attributes of Model properties,
+  such as verbose_name, from within a Django template.  This class works
+  around that limitation by creating an inner Form class per Model class,
+  since an unbound Form object contains (most of?) the property attributes
+  attached to each corresponding Form field.
+  
+  Some are attributes are renamed during the conversion from a Model Property
+  to a Form field; for example, verbose_name becomes label.  This is tolerable
+  because any actual Form code refers to these new names, so they are should
+  be familiar to view creators.  
+  """
+
+  _fields_cache = None
+  
+  @classmethod
+  def fields(cls):
+    """Called by the Django template engine during template instantiation.
+    
+    Since the attribute names use the Form fields naming instead of the
+    Property attribute naming, accessing, for example:
+      {{ entity.property.verbose_name }}
+    is accomplished using:
+      {{ entity.fields.property.label }}
+    
+    Args:
+      cls: Model class, so that each Model class can create its own
+        unbound Form the first time fields() is called by the Django
+        template engine.
+ 
+    Returns:
+      A (created-on-first-use) unbound Form object that can be used to
+      access Property attributes that are not accessible from the
+      Property itself via the Model entity.
+    """
+    if not cls._fields_cache or (cls != cls._fields_cache.__class__.Meta.model):
+      class FieldsProxy(forms_helpers.DbModelForm):
+        """Form used as a proxy to access User model properties attributes.
+        """
+      
+        class Meta:
+          """Inner Meta class that pairs the User Model with this "form".
+          """
+          #: db.Model subclass for which to access model properties attributes
+          model = cls
+      
+      cls._fields_cache = FieldsProxy()
+
+    return cls._fields_cache