Don't serialize stings

elasticsearch/serializer.py

@@ -16,6 +16,10 @@ class JSONSerializer(object):
             raise SerializationError(e)
 
     def dumps(self, data):
+        # don't serialize strings
+        if isinstance(data, (type(''), type(u''))):
+            return data
+
         try:
             return json.dumps(data, default=self.default)
         except (ValueError, TypeError) as e:

elasticsearch/transport.py

@@ -207,7 +207,7 @@ class Transport(object):
         :arg body: body of the request, will be serializes using serializer and
             passed to the connection
         """
-        if body:
+        if body is not None:
             body = self.serializer.dumps(body)
 
         for attempt in range(self.max_retries + 1):

test_elasticsearch/test_serializer.py

@@ -15,3 +15,6 @@ class TestJSONSerializer(TestCase):
         self.assertRaises(SerializationError, JSONSerializer().loads, object())
         self.assertRaises(SerializationError, JSONSerializer().loads, '')
         self.assertRaises(SerializationError, JSONSerializer().loads, '{{')
+
+    def test_strings_are_left_untouched(self):
+        self.assertEquals('Hello World!', JSONSerializer().dumps('Hello World!'))

test_elasticsearch/test_transport.py

@@ -3,7 +3,7 @@ from unittest import TestCase
 
 from elasticsearch.transport import Transport
 from elasticsearch.connection import Connection
-from elasticsearch.exceptions import TransportError, ConnectionError
+from elasticsearch.exceptions import ConnectionError
 
 class DummyConnection(Connection):
     def __init__(self, **kwargs):