fix: Ensure result storage is passed results in bytes

When results are text, such as JSON content for `/meta/` endpoints,
ensure the results are converted to bytes before passing them to a
result storage.

Fix #1577

tests/handlers/test_base_handler_with_result_storage.py

@@ -8,6 +8,7 @@
 # http://www.opensource.org/licenses/mit-license
 # Copyright (c) 2011 globo.com thumbor@googlegroups.com
 
+import json
 import os
 from os.path import dirname
 from shutil import which
@@ -77,6 +78,34 @@ async def test_saves_image_to_result_storage(self, instance_mock):
         expect(expected_path).to_exist()
         expect(response.body).to_be_similar_to(animated_image())
 
+    @patch("tornado.ioloop.IOLoop.instance")
+    @gen_test
+    async def test_saves_meta_to_result_storage(self, instance_mock):
+        instance_mock.return_value = self.io_loop
+        response = await self.async_fetch(
+            "/oGi9XL4nHJKGEKVHjHEp1Jg1KpM=/meta/animated.gif"
+        )
+        expect(response.code).to_equal(200)
+
+        self.context.request = Mock(
+            accepts_webp=False,
+        )
+        expected_path = self.result_storage.normalize_path(
+            "/oGi9XL4nHJKGEKVHjHEp1Jg1KpM=/meta/animated.gif"
+        )
+        expect(expected_path).to_exist()
+
+        expected_source = {
+            "frameCount": 2,
+            "height": 100,
+            "url": "animated.gif",
+            "width": 100,
+        }
+        metadata = json.loads(response.body)
+        expect(metadata).to_include("thumbor")
+        expect(metadata["thumbor"]).to_include("source")
+        expect(metadata["thumbor"]["source"]).to_be_like(expected_source)
+
 
 class ImageOperationsResultStorageOnlyTestCase(BaseImagingTestCase):
     def get_context(self):

thumbor/handlers/__init__.py

@@ -657,11 +657,17 @@ async def finish_request(self, result_from_storage=None):
         await self._write_results_to_client(results, content_type)
 
         if should_store:
+            results = self._ensure_bytes(results)
             await self._store_results(result_storage, metrics, results)
 
         # can't cleanup before storing results as the storage requires context
         self._cleanup()
 
+    def _ensure_bytes(self, results):
+        if isinstance(results, str):
+            return results.encode()
+        return results
+
     def _cleanup(self):
         self.context.request_handler = None