required=False allows omission of value for output. Closes #2342

2 files changed, 9 insertions, 1 deletions

diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index aab80982..cc9410aa 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -288,6 +288,8 @@ class Field(object):
         try:
             return get_attribute(instance, self.source_attrs)
         except (KeyError, AttributeError) as exc:
+            if not self.required and self.default is empty:
+                raise SkipField()
             msg = (
                 'Got {exc_type} when attempting to get a value for field '
                 '`{field}` on serializer `{serializer}`.\nThe serializer '
diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py
index 6f89df0d..53f092d7 100644
--- a/rest_framework/serializers.py
+++ b/rest_framework/serializers.py
@@ -419,8 +419,14 @@ class Serializer(BaseSerializer):
         fields = [field for field in self.fields.values() if not field.write_only]
 
         for field in fields:
-            attribute = field.get_attribute(instance)
+            try:
+                attribute = field.get_attribute(instance)
+            except SkipField:
+                continue
+
             if attribute is None:
+                # We skip `to_representation` for `None` values so that
+                # fields do not have to explicitly deal with that case.
                 ret[field.field_name] = None
             else:
                 ret[field.field_name] = field.to_representation(attribute)