SerializerMethodResourceField

This refactor separates the dynamic related data feature introduced
in #146 from the regular ResourceRelatedField, instead placing it
in the new SerializerMethodResourceField. As discussed on gitter.

Author: Leifur Halldor Asgeirsson

example/serializers.py

@@ -26,7 +26,7 @@ def __init__(self, *args, **kwargs):
 
     comments = relations.ResourceRelatedField(
             source='comment_set', many=True, read_only=True)
-    suggested = relations.ResourceRelatedField(
+    suggested = relations.SerializerMethodResourceField(
             source='get_suggested', model=Entry, read_only=True)
 
     def get_suggested(self, obj):

rest_framework_json_api/relations.py

@@ -107,14 +107,6 @@ def get_links(self, obj=None, lookup_field='pk'):
             return_data.update({'related': related_link})
         return return_data
 
-    def get_attribute(self, instance):
-        # check for a source fn defined on the serializer instead of the model
-        if self.source and hasattr(self.parent, self.source):
-            serializer_method = getattr(self.parent, self.source)
-            if hasattr(serializer_method, '__call__'):
-                return serializer_method(instance)
-        return super(ResourceRelatedField, self).get_attribute(instance)
-
     def to_internal_value(self, data):
         if isinstance(data, six.text_type):
             data = json.loads(data)
@@ -149,3 +141,12 @@ def choices(self):
             for item in queryset
         ])
 
+
+class SerializerMethodResourceField(ResourceRelatedField):
+    def get_attribute(self, instance):
+        # check for a source fn defined on the serializer instead of the model
+        if self.source and hasattr(self.parent, self.source):
+            serializer_method = getattr(self.parent, self.source)
+            if hasattr(serializer_method, '__call__'):
+                return serializer_method(instance)
+        return super(ResourceRelatedField, self).get_attribute(instance)