Return content-length header in download requests

Change-Id: Ifc7ff18bcedf8de4ee809ccc613956dc543a269e

glare/api/v1/resource.py

@@ -484,8 +484,8 @@ class ResponseSerializer(api_versioning.VersionedResource,
         response.headers['Content-MD5'] = meta['md5']
         response.headers['X-Openstack-Glare-Content-SHA1'] = meta['sha1']
         response.headers['X-Openstack-Glare-Content-SHA256'] = meta['sha256']
-        response.headers['Content-Length'] = str(meta['size'])
         response.app_iter = iter(data)
+        response.content_length = str(meta['size'])
 
     @staticmethod
     def _serialize_location(response, result):

glare/tests/functional/test_sample_artifact.py

@@ -17,6 +17,7 @@ import hashlib
 import uuid
 
 from oslo_serialization import jsonutils
+import requests
 
 from glare.tests.functional import base
 
@@ -777,6 +778,11 @@ class TestBlobs(base.TestArtifact):
         self.assertEqual(sha1, art['blob']['sha1'])
         self.assertEqual(sha256, art['blob']['sha256'])
 
+        # check that content-length is in response
+        response = requests.get(self._url(url + '/blob'),
+                                headers=self._headers())
+        self.assertEqual('27', response.headers["content-length"])
+
         blob_data = self.get(url=url + '/blob')
         self.assertEqual(data, blob_data)