From 035d1e99a9cca495b110c4ed426cb877fabac5b1 Mon Sep 17 00:00:00 2001
From: Michal Danilak <mimino.coder@gmail.com>
Date: Thu, 3 Jan 2013 01:42:04 +0100
Subject: [PATCH 1/2] Added model validation to DjangoItem.

---
 scrapy/contrib/djangoitem.py             | 51 +++++++++++++++++++++---
 scrapy/tests/test_djangoitem/__init__.py | 36 ++++++++++++++++-
 2 files changed, 81 insertions(+), 6 deletions(-)

diff --git a/scrapy/contrib/djangoitem.py b/scrapy/contrib/djangoitem.py
index 571dace5c..0b9b3b6f6 100644
--- a/scrapy/contrib/djangoitem.py
+++ b/scrapy/contrib/djangoitem.py
@@ -1,3 +1,5 @@
+from django.core.exceptions import ValidationError
+
 from scrapy.item import Field, Item, ItemMeta
 
 
@@ -24,10 +26,49 @@ class DjangoItem(Item):
 
     django_model = None
 
+    def __init__(self, *args, **kwargs):
+        super(DjangoItem, self).__init__(*args, **kwargs)
+        self._instance = None
+        self._errors = None
+
     def save(self, commit=True):
-        modelargs = dict((k, self.get(k)) for k in self._values
-                         if k in self._model_fields)
-        model = self.django_model(**modelargs)
         if commit:
-            model.save()
-        return model
+            self.instance.save()
+        return self.instance
+
+    def is_valid(self, exclude=None):
+        self._get_errors(exclude)
+        return not bool(self._errors)
+
+    def _get_errors(self, exclude=None):
+        if self._errors is not None:
+            return self._errors
+
+        self._errors = {}
+        if exclude is None:
+            exclude = []
+
+        try:
+            self.instance.clean_fields(exclude=exclude)
+        except ValidationError, e:
+            self._errors = e.update_error_dict(self._errors)
+
+        try:
+            self.instance.clean()
+        except ValidationError, e:
+            self._errors = e.update_error_dict(self._errors)
+
+        # uniqueness is not checked, because it is faster to check it when
+        # saving object to database. Just beware, that failed save()
+        # raises IntegrityError instead of ValidationError.
+
+        return self._errors
+    errors = property(_get_errors)
+
+    @property
+    def instance(self):
+        if self._instance is None:
+            modelargs = dict((k, self.get(k)) for k in self._values
+                             if k in self._model_fields)
+            self._instance = self.django_model(**modelargs)
+        return self._instance
diff --git a/scrapy/tests/test_djangoitem/__init__.py b/scrapy/tests/test_djangoitem/__init__.py
index 7f413825d..9f1dc686a 100644
--- a/scrapy/tests/test_djangoitem/__init__.py
+++ b/scrapy/tests/test_djangoitem/__init__.py
@@ -34,7 +34,7 @@ class IdentifiedPersonItem(DjangoItem):
 
 
 class DjangoItemTest(unittest.TestCase):
-    
+
     def setUp(self):
         if not django:
             raise unittest.SkipTest("Django is not available")
@@ -74,9 +74,43 @@ class DjangoItemTest(unittest.TestCase):
         i = OverrideFieldPersonItem()
 
         i['name'] = 'John'
+        # it is not obvious that "age" should be saved also, since it was
+        # redefined in child class
+        i['age'] = '22'
         person = i.save(commit=False)
 
         self.assertEqual(person.name, 'John')
+        self.assertEqual(person.age, '22')
+
+    def test_validation(self):
+        long_name = 'z' * 300
+        i = BasePersonItem(name=long_name)
+        self.assertFalse(i.is_valid())
+        self.assertDictEqual(
+            {
+                'age': [u'This field cannot be null.'],
+                'name': [u'Ensure this value has at most 255 characters (it has 300).']
+            },
+            i.errors)
+
+        i = BasePersonItem(name='John', age='22')
+        self.assertDictEqual({}, i.errors)
+        self.assertTrue(i.is_valid())
+
+        # once the item is validated, it does not validate again
+        i['name'] = long_name
+        self.assertTrue(i.is_valid())
+
+    def test_override_validation(self):
+        i = OverrideFieldPersonItem()
+        i['name'] = 'John'
+        self.assertFalse(i.is_valid())
+
+        i = i = OverrideFieldPersonItem()
+        i['name'] = 'John'
+        i['age'] = '22'
+        self.assertTrue(i.is_valid())
+
 
     def test_default_field_values(self):
         i = BasePersonItem()

From 2cfbd13c17085f282a74cc7ff2c898590e7fe4c0 Mon Sep 17 00:00:00 2001
From: Michal Danilak <mimino.coder@gmail.com>
Date: Thu, 3 Jan 2013 02:01:04 +0100
Subject: [PATCH 2/2] Added "exclude" parameter testing to unittests.

---
 scrapy/tests/test_djangoitem/__init__.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scrapy/tests/test_djangoitem/__init__.py b/scrapy/tests/test_djangoitem/__init__.py
index 9f1dc686a..8a8b341e6 100644
--- a/scrapy/tests/test_djangoitem/__init__.py
+++ b/scrapy/tests/test_djangoitem/__init__.py
@@ -93,9 +93,9 @@ class DjangoItemTest(unittest.TestCase):
             },
             i.errors)
 
-        i = BasePersonItem(name='John', age='22')
+        i = BasePersonItem(name='John')
+        self.assertTrue(i.is_valid(exclude=['age']))
         self.assertDictEqual({}, i.errors)
-        self.assertTrue(i.is_valid())
 
         # once the item is validated, it does not validate again
         i['name'] = long_name