Merge fixes for 'blank=True' fields. Fixes #324, Fixes #325

Thanks to @Roarster.

rest_framework/fields.py

@@ -114,7 +114,7 @@ class WritableField(Field):
 
     def __init__(self, source=None, read_only=False, required=None,
                  validators=[], error_messages=None, widget=None,
-                 default=None):
+                 default=None, blank=None):
 
         super(WritableField, self).__init__(source=source)
 
@@ -133,6 +133,7 @@ class WritableField(Field):
 
         self.validators = self.default_validators + validators
         self.default = default or self.default
+        self.blank = blank
 
         # Widgets are ony used for HTML forms.
         widget = widget or self.widget
@@ -467,6 +468,16 @@ class CharField(WritableField):
         if max_length is not None:
             self.validators.append(validators.MaxLengthValidator(max_length))
 
+    def validate(self, value):
+        """
+        Validates that the value is supplied (if required).
+        """
+        # if empty string and allow blank
+        if self.blank and not value:
+            return
+        else:
+            super(CharField, self).validate(value)
+
     def from_native(self, value):
         if isinstance(value, basestring) or value is None:
             return value

rest_framework/serializers.py

@@ -393,6 +393,9 @@ class ModelSerializer(Serializer):
         Creates a default instance of a basic non-relational field.
         """
         kwargs = {}
+
+        kwargs['blank'] = model_field.blank
+
         if model_field.null:
             kwargs['required'] = False
 

rest_framework/tests/models.py

@@ -121,3 +121,8 @@ class BlogPostComment(RESTFrameworkModel):
 class Person(RESTFrameworkModel):
     name = models.CharField(max_length=10)
     age = models.IntegerField(null=True, blank=True)
+
+
+# Model for issue #324
+class BlankFieldModel(RESTFrameworkModel):
+    title = models.CharField(max_length=100, blank=True)

rest_framework/tests/serializer.py

@@ -449,3 +449,52 @@ class ManyRelatedTests(TestCase):
         }
 
         self.assertEqual(serializer.data, expected)
+
+
+# Test for issue #324
+class BlankFieldTests(TestCase):
+    def setUp(self):
+
+        class BlankFieldModelSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = BlankFieldModel
+
+        class BlankFieldSerializer(serializers.Serializer):
+            title = serializers.CharField(blank=True)
+
+        class NotBlankFieldModelSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = BasicModel
+
+        class NotBlankFieldSerializer(serializers.Serializer):
+            title = serializers.CharField()
+
+        self.model_serializer_class = BlankFieldModelSerializer
+        self.serializer_class = BlankFieldSerializer
+        self.not_blank_model_serializer_class = NotBlankFieldModelSerializer
+        self.not_blank_serializer_class = NotBlankFieldSerializer
+        self.data = {'title': ''}
+
+    def test_create_blank_field(self):
+        serializer = self.serializer_class(self.data)
+        self.assertEquals(serializer.is_valid(), True)
+
+    def test_create_model_blank_field(self):
+        serializer = self.model_serializer_class(self.data)
+        self.assertEquals(serializer.is_valid(), True)
+
+    def test_create_not_blank_field(self):
+        """
+        Test to ensure blank data in a field not marked as blank=True
+        is considered invalid in a non-model serializer
+        """
+        serializer = self.not_blank_serializer_class(self.data)
+        self.assertEquals(serializer.is_valid(), False)
+
+    def test_create_model_not_blank_field(self):
+        """
+        Test to ensure blank data in a field not marked as blank=True
+        is considered invalid in a model serializer
+        """
+        serializer = self.not_blank_model_serializer_class(self.data)
+        self.assertEquals(serializer.is_valid(), False)