Merge pull request #477 from roberts81/master

Fix for #460

rest_framework/serializers.py

@@ -22,7 +22,16 @@ class DictWithMetadata(dict):
     """
     A dict-like object, that can have additional properties attached.
     """
-    pass
+    def __getstate__(self):
+        """
+        Used by pickle (e.g., caching).
+        Overriden to remove metadata from the dict, since it shouldn't be pickled
+        and may in some instances be unpickleable.
+        """
+        # return an instance of the first dict in MRO that isn't a DictWithMetadata
+        for base in self.__class__.__mro__:
+            if not isinstance(base, DictWithMetadata) and isinstance(base, dict):
+                return base(self)
 
 
 class SortedDictWithMetadata(SortedDict, DictWithMetadata):

rest_framework/tests/serializer.py

@@ -1,4 +1,4 @@
-import datetime
+import datetime, pickle
 from django.test import TestCase
 from rest_framework import serializers
 from rest_framework.tests.models import (ActionItem, Anchor, BasicModel,
@@ -682,3 +682,27 @@ class BlankFieldTests(TestCase):
         """
         serializer = self.not_blank_model_serializer_class(data=self.data)
         self.assertEquals(serializer.is_valid(), False)
+
+
+#test for issue #460
+class SerializerPickleTests(TestCase):
+    """
+    Test pickleability of the output of Serializers
+    """
+    def test_pickle_simple_model_serializer_data(self):
+        """
+        Test simple serializer
+        """
+        pickle.dumps(PersonSerializer(Person(name="Methusela", age=969)).data)
+
+    def test_pickle_inner_serializer(self):
+        """
+        Test pickling a serializer whose resulting .data (a SortedDictWithMetadata) will
+        have unpickleable meta data--in order to make sure metadata doesn't get pulled into the pickle.
+        See DictWithMetadata.__getstate__
+        """
+        class InnerPersonSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = Person
+                fields = ('name', 'age')
+        pickle.dumps(InnerPersonSerializer(Person(name="Noah", age=950)).data)