Updates for pull request review comments

* Remove ListOrObjectField
* Allow item_field & value_field to be optional
* Undo from_native API change; flex invocation in compound fields
* In DictField, coerce key to a string
* If list or dict is None or empty, just return input preserving empty containers
* Remove dict comprehension for Python 2.6 compat

rest_framework/compound_fields.py

@@ -0,0 +1,71 @@
+"""
+Compound fields for processing values that are lists and dicts of values described by embedded
+fields.
+"""
+from .fields import WritableField
+from .serializers import BaseSerializer
+
+
+def field_or_serializer_from_native(field_or_serializer, data):
+    if isinstance(field_or_serializer, BaseSerializer):
+        return field_or_serializer.from_native(data, None)
+    return field_or_serializer.from_native(data)
+
+
+class ListField(WritableField):
+    """
+    A field whose values are lists of items described by the given item field. The item field can
+    be another field type (e.g., CharField) or a serializer.
+    """
+
+    def __init__(self, item_field=None, *args, **kwargs):
+        super(ListField, self).__init__(*args, **kwargs)
+        self.item_field = item_field
+
+    def to_native(self, obj):
+        if obj:
+            return [
+                self.item_field.to_native(item) if self.item_field else item
+                for item in obj
+            ]
+        return obj
+
+    def from_native(self, data):
+        if data:
+            return [
+                field_or_serializer_from_native(self.item_field, item_data)
+                if self.item_field else item_data
+                for item_data in data
+            ]
+        return data
+
+
+class DictField(WritableField):
+    """
+    A field whose values are dicts of values described by the given value field. The value field
+    can be another field type (e.g., CharField) or a serializer.
+    """
+
+    def __init__(self, value_field=None, *args, **kwargs):
+        super(DictField, self).__init__(*args, **kwargs)
+        self.value_field = value_field
+
+    def to_native(self, obj):
+        if obj:
+            return dict(
+                (key, self.value_field.to_native(value) if self.value_field else value)
+                for key, value in obj.items()
+            )
+        return obj
+
+    def from_native(self, data):
+        if data:
+            return dict(
+                (
+                    unicode(key),
+                    field_or_serializer_from_native(self.value_field, value)
+                    if self.value_field else value
+                )
+                for key, value in data.items()
+            )
+        return data

rest_framework/fields.py

@@ -1012,78 +1012,3 @@ class SerializerMethodField(Field):
     def field_to_native(self, obj, field_name):
         value = getattr(self.parent, self.method_name)(obj)
         return self.to_native(value)
-
-
-##### Compound Typed Fields #####
-
-
-class ListField(WritableField):
-    """
-    A field whose values are lists of items described by the given item field. The item field can
-    be another field type (e.g., CharField) or a serializer.
-    """
-
-    def __init__(self, item_field, *args, **kwargs):
-        super(ListField, self).__init__(*args, **kwargs)
-        self.item_field = item_field
-
-    def to_native(self, obj):
-        if obj:
-            return [
-                self.item_field.to_native(item)
-                for item in obj
-            ]
-
-    def from_native(self, data):
-        if data:
-            return [
-                self.item_field.from_native(item_data)
-                for item_data in data
-            ]
-
-
-class ListOrObjectField(WritableField):
-    """
-    A field whose values are either objects or lists of items described by the given item field.
-    The item field can be another field type (e.g., CharField) or a serializer.
-    """
-
-    def __init__(self, item_field, *args, **kwargs):
-        super(ListOrObjectField, self).__init__(*args, **kwargs)
-        self.item_field = item_field
-        self.list_field = ListField(item_field)
-
-    def to_native(self, obj):
-        if isinstance(obj, list):
-            return self.list_field.to_native(obj)
-        return self.item_field.to_native(obj)
-
-    def from_native(self, data):
-        if isinstance(obj, list):
-            return self.list_field.from_native(obj)
-        return self.item_field.from_native(obj)
-
-
-class DictField(WritableField):
-    """
-    A field whose values are dicts of values described by the given value field. The value field
-    can be another field type (e.g., CharField) or a serializer.
-    """
-
-    def __init__(self, value_field, *args, **kwargs):
-        super(DictField, self).__init__(*args, **kwargs)
-        self.value_field = value_field
-
-    def to_native(self, obj):
-        if obj:
-            return {
-                key:self.value_field.to_native(value)
-                for key, value in obj.items()
-            }
-
-    def from_native(self, data):
-        if data:
-            return {
-                key:self.value_field.from_native(value)
-                for key, value in data.items()
-            }

rest_framework/serializers.py

@@ -331,7 +331,7 @@ class BaseSerializer(WritableField):
 
         return ret
 
-    def from_native(self, data, files=None):
+    def from_native(self, data, files):
         """
         Deserialize primitives -> objects.
         """