made DjangoItem a descendant of Item and its metaclass

scrapy/contrib_exp/djangoitem.py

@@ -1,7 +1,7 @@
-from scrapy.item import DictItem, Field
+from scrapy.item import Field, Item, ItemMeta
 
 
-class DjangoItemMeta(type):
+class DjangoItemMeta(ItemMeta):
 
     def  __new__(mcs, class_name, bases, attrs):
         cls = super(DjangoItemMeta, mcs).__new__(mcs, class_name, bases, attrs)
@@ -12,17 +12,14 @@ class DjangoItemMeta(type):
             cls._model_meta = cls.django_model._meta
             for model_field in cls._model_meta.fields:
                 # XXX: for now we're treating each PK as autogenerated field
-                if model_field != cls._model_meta.pk:
+                if model_field != cls._model_meta.pk and \
+                   model_field.name not in cls.fields:
                     cls.fields[model_field.name] = Field()
                     cls._model_fields.append(model_field.name)
-            # add declared fields
-            for n, v in attrs.iteritems():
-                if isinstance(v, Field):
-                    cls.fields[n] = v
         return cls
 
 
-class DjangoItem(DictItem):
+class DjangoItem(Item):
 
     __metaclass__ = DjangoItemMeta
 

scrapy/item.py

@@ -17,7 +17,7 @@ class Field(dict):
     """Container of field metadata"""
 
 
-class _ItemMeta(type):
+class ItemMeta(type):
 
     def __new__(mcs, class_name, bases, attrs):
         fields = {}
@@ -81,7 +81,7 @@ class DictItem(DictMixin, BaseItem):
 
 class Item(DictItem):
 
-    __metaclass__ = _ItemMeta
+    __metaclass__ = ItemMeta
 
 
 class ScrapedItem(BaseItem):