Always convert header values to str()

botocore/serialize.py

@@ -483,7 +483,7 @@ def _partition_parameters(self, partitioned, param_name,
         elif location == 'header':
             shape = shape_members[param_name]
             value = self._convert_header_value(shape, param_value)
-            partitioned['headers'][key_name] = value
+            partitioned['headers'][key_name] = str(value)
         elif location == 'headers':
             # 'headers' is a bit of an oddball.  The ``key_name``
             # is actually really a prefix for the header names:

tests/functional/test_s3.py

@@ -206,3 +206,21 @@ def test_provided_endpoint_url_for_path_addressing(self):
             request_sent = mock_send.call_args[0][0]
             self.assertEqual(
                 'https://foo.amazonaws.com/mybucket/mykey', request_sent.url)
+
+
+class TestCanSendIntegerHeaders(BaseSessionTest):
+
+    def test_int_values_with_sigv4(self):
+        s3 = self.session.create_client(
+            's3', config=Config(signature_version='s3v4'))
+        with mock.patch('botocore.endpoint.Session.send') as mock_send:
+            mock_send.return_value = mock.Mock(status_code=200,
+                                               content=b'',
+                                               headers={})
+            s3.upload_part(Bucket='foo', Key='bar', Body=b'foo',
+                           UploadId='bar', PartNumber=1, ContentLength=3)
+            headers = mock_send.call_args[0][0].headers
+            # Verify that the request integer value of 3 has been converted to
+            # string '3'.  This also means we've made it pass the signer which
+            # expects string values in order to sign properly.
+            self.assertEqual(headers['Content-Length'], '3')

tests/unit/test_serialize.py

@@ -402,3 +402,41 @@ def test_instantiate_with_validation(self):
 
         with self.assertRaises(ParamValidationError):
             self.assert_serialize_invalid_parameter(request_serializer)
+
+
+class TestHeaderSerialization(BaseModelWithBlob):
+    def setUp(self):
+        self.model = {
+            'metadata': {'protocol': 'rest-xml', 'apiVersion': '2014-01-01'},
+            'documentation': '',
+            'operations': {
+                'TestOperation': {
+                    'name': 'TestOperation',
+                    'http': {
+                        'method': 'POST',
+                        'requestUri': '/',
+                    },
+                    'input': {'shape': 'InputShape'},
+                }
+            },
+            'shapes': {
+                'InputShape': {
+                    'type': 'structure',
+                    'members': {
+                        'ContentLength': {
+                            'shape': 'Integer',
+                            'location': 'header',
+                            'locationName': 'Content-Length'
+                        },
+                    }
+                },
+                'Integer': {
+                    'type': 'integer'
+                },
+            }
+        }
+        self.service_model = ServiceModel(self.model)
+
+    def test_always_serialized_as_str(self):
+        request = self.serialize_to_request({'ContentLength': 100})
+        self.assertEqual(request['headers']['Content-Length'], '100')