use ItemAdaptor.__classinit__ to set field_adaptors, also make defaulted field adaptors static_methods

--HG--
extra : convert_revision : svn%3Ab85faa78-f9eb-468e-a121-7cced6da292c%40967

scrapy/trunk/scrapy/contrib_exp/newitem/adaptors.py

@@ -7,53 +7,51 @@ def is_adaptor(func):
 
 class ItemAdaptor(Declarative):
 
+    item_class = None
+    default_adaptor = None
+    field_adaptors = {}
+
     def __classinit__(cls, attrs):
-        # defines adaptors as staticmethods
-        for n, v in attrs.items():
-            if is_adaptor(v):
-                setattr(cls, n, staticmethod(v))
+        cls.field_adaptors = cls.field_adaptors.copy()
+        if cls.item_class:
+            # set new adaptors
+            for n, v in attrs.items():
+                if n in cls.item_class.fields.keys() and is_adaptor(v):
+                    cls.set_adaptor(n, v)
+            
+            # if default_adaptor is set, use it for the unadapted fields
+            if cls.default_adaptor:
+                for field in cls.item_class.fields.keys():
+                    if field not in cls.field_adaptors.keys():
+                        cls.set_adaptor(field, cls.default_adaptor.im_func)
+
+    @classmethod
+    def set_adaptor(cls, name, func):
+        cls.field_adaptors[name] = func
+        # define adaptor as a staticmethod
+        setattr(cls, name, staticmethod(func))
 
     def __init__(self, response=None, item=None):
         self.item_instance = item if item else self.item_class()
         self._response = response
-        self._field_adaptors = self._get_field_adaptors()
-        self._default_adaptor = self._get_default_adaptor()
-
-    def _get_field_adaptors(self):
-        fa = {}
-        for field in self.item_instance.fields.keys():
-            try:
-                fa[field] = object.__getattribute__(self, field)
-            except:
-                pass
-
-        return fa
-
-    def _get_default_adaptor(self):
-        try:
-            return object.__getattribute__(self, 'default_adaptor')
-        except:
-            return None
 
     def __setattr__(self, name, value):
-        if name.startswith('_') or name == 'item_instance' \
-                or name == 'default_adaptor':
+        if (name.startswith('_') or name == 'item_instance' \
+            or name == 'default_adaptor' or name == 'field_adaptors'):
             return object.__setattr__(self, name, value)
 
         try:
-            fa = self._field_adaptors[name]
+            fa = self.field_adaptors[name]
         except KeyError:
-            if self._default_adaptor:
-                fa = self._default_adaptor
-            else:
-                return setattr(self.item_instance, name, value)
+            return setattr(self.item_instance, name, value)
 
         adaptor_args = {'response': self._response, 'item': self.item_instance}
         ovalue = fa(value, adaptor_args=adaptor_args)
         setattr(self.item_instance, name, ovalue)
 
     def __getattribute__(self, name):
-        if name.startswith('_') or name.startswith('item_'):
+        if (name.startswith('_') or name.startswith('item_') \
+            or name == 'default_adaptor' or name == 'field_adaptors'):
             return object.__getattribute__(self, name)
 
         return getattr(self.item_instance, name)

scrapy/trunk/scrapy/tests/test_itemadaptor.py

@@ -1,4 +1,3 @@
-
 import unittest
 import string
 from scrapy.contrib_exp.newitem.adaptors import adaptor, ItemAdaptor
@@ -10,6 +9,7 @@ class TestItem(Item):
     url = StringField()
     summary = StringField()
 
+
 class TestAdaptor(ItemAdaptor):
     item_class = TestItem
     name = lambda v, adaptor_args: v.title()
@@ -29,7 +29,7 @@ class ItemAdaptorTest(unittest.TestCase):
             default_adaptor = lambda v, adaptor_args: v.title()
 
         dta = DefaultedTestAdaptor()
-        assert dta._default_adaptor
+        assert dta.default_adaptor
         dta.name = 'marta'
         assert dta.name == 'Marta'
 
@@ -38,8 +38,8 @@ class ItemAdaptorTest(unittest.TestCase):
             url = lambda v, adaptor_args: v.lower()
 
         ia = ChildTestAdaptor()
-        assert 'url' in ia._field_adaptors
-        assert 'name' in ia._field_adaptors
+        assert 'url' in ia.field_adaptors
+        assert 'name' in ia.field_adaptors
 
         ia.url = 'HTTP://scrapy.ORG'
         self.assertEqual(ia.url, 'http://scrapy.org')
@@ -47,16 +47,14 @@ class ItemAdaptorTest(unittest.TestCase):
         ia.name = 'marta'
         self.assertEqual(ia.name, 'Marta')
 
-
         class ChildChildTestAdaptor(ChildTestAdaptor):
             url = lambda v, adaptor_args: v.upper()
             summary = lambda v, adaptor_args: v
 
         ia = ChildChildTestAdaptor()
-        assert 'url' in ia._field_adaptors
-        assert 'name' in ia._field_adaptors
-        assert 'summary' in ia._field_adaptors
-
+        assert 'url' in ia.field_adaptors
+        assert 'name' in ia.field_adaptors
+        assert 'summary' in ia.field_adaptors
 
         ia.url = 'HTTP://scrapy.ORG'
         self.assertEqual(ia.url, 'HTTP://SCRAPY.ORG')
@@ -75,7 +73,17 @@ class ItemAdaptorTest(unittest.TestCase):
         ia.name = 'Marta'
         self.assertEqual(ia.name, 'mARTA')
 
+    def test_staticdefaults(self):
+        class ParentAdaptorDefaulted(ItemAdaptor):
+            item_class = TestItem
+            default_adaptor = lambda v, adaptor_args: v.title()
 
+        class ChildAdaptorDefaulted(ParentAdaptorDefaulted):
+            name = adaptor(ParentAdaptorDefaulted.name, string.swapcase)
+
+        dia = ChildAdaptorDefaulted()
+        dia.name = 'marta'
+        self.assertEqual(dia.name, 'mARTA')
 
 
 class TreeadaptTest(unittest.TestCase):
@@ -109,7 +117,6 @@ class TreeadaptTest(unittest.TestCase):
         self.assertEqual(ad(0, {'add_value': 3}), [3])
         self.assertEqual(ad(0), [5])
 
-
     def test_4_treelogic(self):
         split1 = lambda v: v.split('&')
         split2 = lambda v: v.split('=')