Add compound field types

rest_framework/fields.py

@@ -1012,3 +1012,78 @@ 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):
+    def from_native(self, data, files=None):
         """
         Deserialize primitives -> objects.
         """