parse legacy and native bool in legacy bool (#158)

Author: jmphilli

pynamodb/attributes.py

@@ -253,6 +253,17 @@ def serialize(self, value):
     def deserialize(self, value):
         return bool(json.loads(value))
 
+    def get_value(self, value):
+        # we need this for the period in which you are upgrading
+        # you can switch all BooleanAttributes to LegacyBooleanAttributes
+        # this can read both but serializes as Numbers
+        # once you've transitioned, you can then switch back to
+        # BooleanAttribute and it will serialize the new fancy way
+        value_to_deserialize = super(LegacyBooleanAttribute, self).get_value(value)
+        if value_to_deserialize is None:
+            value_to_deserialize = json.dumps(value.get(BOOLEAN, 0))
+        return value_to_deserialize
+
 
 class BooleanAttribute(Attribute):
     """

pynamodb/tests/test_attributes.py

@@ -12,7 +12,7 @@
 from pynamodb.models import Model
 from pynamodb.attributes import (
     BinarySetAttribute, BinaryAttribute, NumberSetAttribute, NumberAttribute,
-    UnicodeAttribute, UnicodeSetAttribute, UTCDateTimeAttribute, BooleanAttribute,
+    UnicodeAttribute, UnicodeSetAttribute, UTCDateTimeAttribute, BooleanAttribute, LegacyBooleanAttribute,
     JSONAttribute, DEFAULT_ENCODING, NUMBER, STRING, STRING_SET, NUMBER_SET, BINARY_SET,
     BINARY, BOOLEAN)
 
@@ -383,6 +383,46 @@ def test_unicode_set_attribute(self):
         self.assertEqual(attr.default, set([six.u('foo'), six.u('bar')]))
 
 
+class LegacyBooleanAttributeTestCase(TestCase):
+    def test_legacy_boolean_attribute_can_read_future_boolean_attributes(self):
+        """
+        LegacyBooleanAttribute.deserialize
+        :return:
+        """
+        attr = LegacyBooleanAttribute()
+        self.assertEqual(attr.deserialize('1'), True)
+        self.assertEqual(attr.deserialize('0'), False)
+        self.assertEqual(attr.deserialize(json.dumps(True)), True)
+        self.assertEqual(attr.deserialize(json.dumps(False)), False)
+
+    def test_legacy_boolean_attribute_get_value_can_read_both(self):
+        """
+        LegacyBooleanAttribute.get_value
+        :return:
+        """
+        attr = LegacyBooleanAttribute()
+        self.assertEqual(attr.get_value({'N': '1'}), '1')
+        self.assertEqual(attr.get_value({'N': '0'}), '0')
+        self.assertEqual(attr.get_value({'BOOL': True}), json.dumps(True))
+        self.assertEqual(attr.get_value({'BOOL': False}), json.dumps(False))
+
+    def test_legacy_boolean_attribute_get_value_and_deserialize_work_together(self):
+        attr = LegacyBooleanAttribute()
+        self.assertEqual(attr.deserialize(attr.get_value({'N': '1'})), True)
+        self.assertEqual(attr.deserialize(attr.get_value({'N': '0'})), False)
+        self.assertEqual(attr.deserialize(attr.get_value({'BOOL': True})), True)
+        self.assertEqual(attr.deserialize(attr.get_value({'BOOL': False})), False)
+
+    def test_legacy_boolean_attribute_serialize(self):
+        """
+        LegacyBooleanAttribute.serialize
+        """
+        attr = LegacyBooleanAttribute()
+        self.assertEqual(attr.serialize(True), '1')
+        self.assertEqual(attr.serialize(False), '0')
+        self.assertEqual(attr.serialize(None), None)
+
+
 class BooleanAttributeTestCase(TestCase):
     """
     Tests boolean attributes