✨ Support dataclasses in responses (#3576)

Co-authored-by: amit lissack <amit@opentrons.com>

fastapi/encoders.py

@@ -1,3 +1,4 @@
+import dataclasses
 from collections import defaultdict
 from enum import Enum
 from pathlib import PurePath
@@ -61,6 +62,8 @@ def jsonable_encoder(
             custom_encoder=encoder,
             sqlalchemy_safe=sqlalchemy_safe,
         )
+    if dataclasses.is_dataclass(obj):
+        return dataclasses.asdict(obj)
     if isinstance(obj, Enum):
         return obj.value
     if isinstance(obj, PurePath):

fastapi/routing.py

@@ -1,4 +1,5 @@
 import asyncio
+import dataclasses
 import email.message
 import enum
 import inspect
@@ -90,6 +91,8 @@ def _prepare_response_content(
             )
             for k, v in res.items()
         }
+    elif dataclasses.is_dataclass(res):
+        return dataclasses.asdict(res)
     return res