Nicer write_only fields implementation. Closes #1355

rest_framework/fields.py

@@ -114,10 +114,6 @@ def strip_multiple_choice_msg(help_text):
     return help_text.replace(multiple_choice_msg, '')
 
 
-class IgnoreFieldException(Exception):
-    pass
-
-
 class Field(object):
     read_only = True
     creation_counter = 0
@@ -329,7 +325,7 @@ class WritableField(Field):
 
     def field_to_native(self, obj, field_name):
         if self.write_only:
-            raise IgnoreFieldException()
+            return None
         return super(WritableField, self).field_to_native(obj, field_name)
 
     def field_from_native(self, data, files, field_name, into):

rest_framework/serializers.py

@@ -346,14 +346,12 @@ class BaseSerializer(WritableField):
                continue
             field.initialize(parent=self, field_name=field_name)
             key = self.get_field_key(field_name)
-            try:
-                value = field.field_to_native(obj, field_name)
-            except IgnoreFieldException:
-                continue
+            value = field.field_to_native(obj, field_name)
             method = getattr(self, 'transform_%s' % field_name, None)
             if callable(method):
                 value = method(obj, value)
-            ret[key] = value
+            if not getattr(field, 'write_only', False):
+                ret[key] = value
             ret.fields[key] = self.augment_field(field, field_name, key, value)
 
         return ret
@@ -389,7 +387,7 @@ class BaseSerializer(WritableField):
         across relationships.
         """
         if self.write_only:
-            raise IgnoreFieldException()
+            return None
 
         if self.source == '*':
             return self.to_native(obj)