fix(asgi.App): correctly pass params when using orjson.dumps (#2102)

* fix: this change fixes an issue when using orjson as json serializer with asyncio

* docs: improve newsfragment

* test: ensure _serialize_async_b is also tested using the app

* docs(newsfragments): capitalize JSON

Co-authored-by: Vytautas Liuolia <vytautas.liuolia@gmail.com>

Author: CaselIT

docs/_newsfragments/2100.bugfix.rst

@@ -0,0 +1,2 @@
+The ``orjson`` library now works correctly when used as JSON serializer in
+the media handlers in the ASGI version of Falcon.

falcon/media/json.py

@@ -181,7 +181,9 @@ def _serialize_s(self, media, content_type=None) -> bytes:
     async def _serialize_async_s(self, media, content_type) -> bytes:
         return self._dumps(media).encode()
 
-    def _serialize_b(self, media, content_type) -> bytes:
+    # NOTE(kgriffs): Make content_type a kwarg to support the
+    #   Request.render_body() shortcut optimization.
+    def _serialize_b(self, media, content_type=None) -> bytes:
         return self._dumps(media)
 
     async def _serialize_async_b(self, media, content_type) -> bytes:

tests/test_media_handlers.py

@@ -55,24 +55,30 @@
     (mujson.loads, b'{"test": "value"}', {'test': 'value'}),
     (ujson.loads, b'{"test": "value"}', {'test': 'value'}),
 ]
+ALL_JSON_IMPL = [
+    (json.dumps, json.loads),
+    (partial(mujson.dumps, ensure_ascii=True), mujson.loads),
+    (ujson.dumps, ujson.loads),
+]
 
 
 if orjson:
     SERIALIZATION_PARAM_LIST += [
         (orjson.dumps, {'test': 'value'}, b'{"test":"value"}'),
     ]
-
     DESERIALIZATION_PARAM_LIST += [
         (orjson.loads, b'{"test": "value"}', {'test': 'value'}),
     ]
+    ALL_JSON_IMPL += [(orjson.dumps, orjson.loads)]
+
 if rapidjson:
     SERIALIZATION_PARAM_LIST += [
         (rapidjson.dumps, {'test': 'value'}, b'{"test":"value"}'),
     ]
-
     DESERIALIZATION_PARAM_LIST += [
         (rapidjson.loads, b'{"test": "value"}', {'test': 'value'}),
     ]
+    ALL_JSON_IMPL += [(rapidjson.dumps, rapidjson.loads)]
 
 
 @pytest.mark.parametrize('func, body, expected', SERIALIZATION_PARAM_LIST)
@@ -114,6 +120,44 @@ def test_deserialization(asgi, func, body, expected):
     assert result == expected
 
 
+@pytest.mark.parametrize('dumps, loads', ALL_JSON_IMPL)
+@pytest.mark.parametrize('subclass', (True, False))
+def test_full_app(asgi, dumps, loads, subclass):
+    if subclass:
+
+        class JSONHandlerSubclass(media.JSONHandler):
+            pass
+
+        handler = JSONHandlerSubclass(dumps=dumps, loads=loads)
+        assert handler._serialize_sync is None
+        assert handler._deserialize_sync is None
+    else:
+        handler = media.JSONHandler(dumps=dumps, loads=loads)
+        assert handler._serialize_sync is not None
+        assert handler._deserialize_sync is not None
+    app = create_app(asgi)
+    app.req_options.media_handlers[falcon.MEDIA_JSON] = handler
+    app.resp_options.media_handlers[falcon.MEDIA_JSON] = handler
+
+    if asgi:
+
+        class Resp:
+            async def on_get(self, req, res):
+                res.media = await req.get_media()
+
+    else:
+
+        class Resp:
+            def on_get(self, req, res):
+                res.media = req.get_media()
+
+    app.add_route('/go', Resp())
+
+    data = {'foo': 123, 'bar': [2, 3], 'baz': {'x': 'y'}}
+    res = testing.simulate_get(app, '/go', json=data)
+    assert res.json == data
+
+
 @pytest.mark.parametrize('monkeypatch_resolver', [True, False])
 @pytest.mark.parametrize(
     'handler_mt',