[soc2009/model-validation] Added clean() and validate() methods to Model.

This also called for ValidationError to also accept dicts as message.

git-svn-id: http://code.djangoproject.com/svn/django/branches/soc2009/model-validation@10869 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/core/exceptions.py

@@ -32,23 +32,33 @@ class FieldError(Exception):
     """Some kind of problem with a model field."""
     pass
 
+NON_FIELD_ERRORS = '__all__'
 class ValidationError(Exception):
     """An error while validating data."""
     def __init__(self, message):
+        import operator
         from django.utils.encoding import force_unicode
         """
         ValidationError can be passed any object that can be printed (usually
-        a string) or a list of objects.
+        a string), a list of objects or a dictionary.
         """
+        if isinstance(message, dict):
+            self.message_dict = message
+            message = reduce(operator.add, message.values())
+
         if isinstance(message, list):
             self.messages = [force_unicode(msg) for msg in message]
         else:
             message = force_unicode(message)
             self.messages = [message]
 
+
+
     def __str__(self):
         # This is needed because, without a __str__(), printing an exception
         # instance would result in this:
         # AttributeError: ValidationError instance has no attribute 'args'
         # See http://www.python.org/doc/current/tut/node10.html#handling
+        if hasattr(self, 'message_dict'):
+            return repr(self.message_dict)
         return repr(self.messages)

django/db/models/base.py

@@ -9,7 +9,7 @@ except NameError:
     from sets import Set as set     # Python 2.3 fallback.
 
 import django.db.models.manager     # Imported to register signal handler.
-from django.core.exceptions import ObjectDoesNotExist, MultipleObjectsReturned, FieldError
+from django.core.exceptions import ObjectDoesNotExist, MultipleObjectsReturned, FieldError, ValidationError, NON_FIELD_ERRORS
 from django.db.models.fields import AutoField, FieldDoesNotExist
 from django.db.models.fields.related import OneToOneRel, ManyToOneRel, OneToOneField
 from django.db.models.query import delete_objects, Q
@@ -597,6 +597,36 @@ class Model(object):
     def prepare_database_save(self, unused):
         return self.pk
 
+    def validate(self):
+        """
+        Hook for doing any extra model-wide validation after Model.clean() been
+        called on every field. Any ValidationError raised by this method will
+        not be associated with a particular field; it will have a special-case
+        association with the field named '__all__'.
+        """
+        pass
+
+    def clean(self):
+        """
+        Cleans all fields and raises ValidationError containing message_dict of 
+        all validation errors if any occur.
+        """
+        errors = {}
+        for f in self._meta.fields:
+            try:
+                # TODO: is the [sg]etattr correct?
+                setattr(self, f.attname, f.clean(getattr(self, f.attname), self))
+            except ValidationError, e:
+                errors[f.name] = e.messages
+        try:
+            # TODO: run this only if not errors??
+            self.validate()
+        except ValidationError, e:
+            errors[NON_FIELD_ERRORS] = e.messages
+
+        if errors:
+            raise ValidationError(errors)
+
 
 ############################################
 # HELPER FUNCTIONS (CURRIED MODEL METHODS) #

tests/modeltests/validation/models.py

@@ -0,0 +1,28 @@
+from datetime import datetime
+
+from django.core.exceptions import ValidationError
+from django.db import models
+from django.test import TestCase
+
+class ModelToValidate(models.Model):
+    name = models.CharField(max_length=100)
+    created = models.DateTimeField(default=datetime.now)
+    number = models.IntegerField()
+
+    def validate(self):
+        super(ModelToValidate, self).validate()
+        if self.number == 11:
+            raise ValidationError('Invalid number supplied!')
+
+class BaseModelValidationTests(TestCase):
+    def test_missing_required_field_raises_error(self):
+        mtv = ModelToValidate()
+        self.assertRaises(ValidationError, mtv.clean)
+    
+    def test_with_correct_value_model_validates(self):
+        mtv = ModelToValidate(number=10)
+        self.assertEqual(None, mtv.clean())
+
+    def test_custom_validate_method_is_called(self):
+        mtv = ModelToValidate(number=11)
+        self.assertRaises(ValidationError, mtv.clean)