merged hmarr's updates

mongoengine/base.py

@@ -136,20 +136,36 @@ class TopLevelDocumentMetaclass(DocumentMetaclass):
         if attrs.get('__metaclass__') == TopLevelDocumentMetaclass:
             return super_new(cls, name, bases, attrs)
 
-        collection = attrs.get('__collection__', name.lower())
+        collection = name.lower()
         
+        simple_class = True
+
         # Subclassed documents inherit collection from superclass
         for base in bases:
             if hasattr(base, '_meta') and 'collection' in base._meta:
+                # Ensure that the Document class may be subclassed - 
+                # inheritance may be disabled to remove dependency on 
+                # additional fields _cls and _types
+                if base._meta.get('allow_inheritance', True) == False:
+                    raise ValueError('Document %s may not be subclassed' %
+                                     base.__name__)
+                else:
+                    simple_class = False
                 collection = base._meta['collection']
 
         meta = {
             'collection': collection,
+            'allow_inheritance': True,
         }
         meta.update(attrs.get('meta', {}))
+        # Only simple classes - direct subclasses of Document - may set
+        # allow_inheritance to False
+        if not simple_class and not meta['allow_inheritance']:
+            raise ValueError('Only direct subclasses of Document may set '
+                             '"allow_inheritance" to False')
         attrs['_meta'] = meta
 
-        attrs['_id'] = ObjectIdField()
+        attrs['id'] = ObjectIdField(name='_id')
 
         # Set up collection manager, needs the class to have fields so use
         # DocumentMetaclass before instantiating CollectionManager object
@@ -168,10 +184,11 @@ class BaseDocument(object):
             if attr_name in values:
                 setattr(self, attr_name, values.pop(attr_name))
             else:
-                if attr_value.required:
+                # Use default value if present
+                value = getattr(self, attr_name, None)
+                if value is None and attr_value.required:
                     raise ValidationError('Field "%s" is required' % attr_name)
-                # Use default value
-                setattr(self, attr_name, getattr(self, attr_name, None))
+                setattr(self, attr_name, value)
 
     @classmethod
     def _get_subclasses(cls):
@@ -226,9 +243,12 @@ class BaseDocument(object):
         for field_name, field in self._fields.items():
             value = getattr(self, field_name, None)
             if value is not None:
-                data[field_name] = field.to_mongo(value)
-        data['_cls'] = self._class_name
-        data['_types'] = self._superclasses.keys() + [self._class_name]
+                data[field.name] = field.to_mongo(value)
+        # Only add _cls and _types if allow_inheritance is not False
+        if not (hasattr(self, '_meta') and
+                self._meta.get('allow_inheritance', True) == False):
+            data['_cls'] = self._class_name
+            data['_types'] = self._superclasses.keys() + [self._class_name]
         return data
     
     @classmethod
@@ -241,6 +261,9 @@ class BaseDocument(object):
 
         data = dict((str(key), value) for key, value in son.items())
 
+        if '_types' in data:
+            del data['_types']
+
         if '_cls' in data:
             del data['_cls']
 
@@ -254,7 +277,7 @@ class BaseDocument(object):
             cls = subclasses[class_name]
 
         for field_name, field in cls._fields.items():
-            if field_name in data:
-                data[field_name] = field.to_python(data[field_name])
+            if field.name in data:
+                data[field_name] = field.to_python(data[field.name])
 
         return cls(**data)