feat(typing): type response (#2304)

* typing: type app

* typing: type websocket module

* typing: type asgi.reader, asgi.structures, asgi.stream

* typing: type most of media

* typing: type multipart

* typing: type response

* style: fix spelling in multipart.py

* style(tests): explain referencing the same property multiple times

* style: fix linter errors

* chore: revert behavioral change to cors middleware.

* chore: do not build rapidjson on PyPy

---------

Co-authored-by: Vytautas Liuolia <[email protected]>

falcon/app.py

@@ -26,7 +26,6 @@
     ClassVar,
     Dict,
     FrozenSet,
-    IO,
     Iterable,
     List,
     Literal,
@@ -62,6 +61,7 @@
 from falcon.typing import ErrorSerializer
 from falcon.typing import FindMethod
 from falcon.typing import ProcessResponseMethod
+from falcon.typing import ReadableIO
 from falcon.typing import ResponderCallable
 from falcon.typing import SinkCallable
 from falcon.typing import SinkPrefix
@@ -1191,7 +1191,9 @@ def _handle_exception(
     def _get_body(
         self,
         resp: Response,
-        wsgi_file_wrapper: Optional[Callable[[IO[bytes], int], Iterable[bytes]]] = None,
+        wsgi_file_wrapper: Optional[
+            Callable[[ReadableIO, int], Iterable[bytes]]
+        ] = None,
     ) -> Tuple[Iterable[bytes], Optional[int]]:
         """Convert resp content into an iterable as required by PEP 333.
 
@@ -1229,11 +1231,13 @@ def _get_body(
                     # TODO(kgriffs): Make block size configurable at the
                     # global level, pending experimentation to see how
                     # useful that would be. See also the discussion on
-                    # this GitHub PR: http://goo.gl/XGrtDz
-                    iterable = wsgi_file_wrapper(stream, self._STREAM_BLOCK_SIZE)
+                    # this GitHub PR:
+                    # https://github.com/falconry/falcon/pull/249#discussion_r11269730
+                    iterable = wsgi_file_wrapper(stream, self._STREAM_BLOCK_SIZE)  # type: ignore[arg-type]
                 else:
                     iterable = helpers.CloseableStreamIterator(
-                        stream, self._STREAM_BLOCK_SIZE
+                        stream,  # type: ignore[arg-type]
+                        self._STREAM_BLOCK_SIZE,
                     )
             else:
                 iterable = stream

falcon/asgi/app.py

@@ -46,7 +46,6 @@
 from falcon.asgi_spec import AsgiSendMsg
 from falcon.asgi_spec import EventType
 from falcon.asgi_spec import WSCloseCode
-from falcon.constants import _UNSET
 from falcon.constants import MEDIA_JSON
 from falcon.errors import CompatibilityError
 from falcon.errors import HTTPBadRequest
@@ -60,6 +59,7 @@
 from falcon.typing import AsgiResponderWsCallable
 from falcon.typing import AsgiSend
 from falcon.typing import AsgiSinkCallable
+from falcon.typing import MISSING
 from falcon.typing import SinkPrefix
 from falcon.util import get_argnames
 from falcon.util.misc import is_python_func
@@ -552,9 +552,9 @@ async def __call__(  # type: ignore[override] # noqa: C901
                     data = resp._data
 
                     if data is None and resp._media is not None:
-                        # NOTE(kgriffs): We use a special _UNSET singleton since
+                        # NOTE(kgriffs): We use a special MISSING singleton since
                         #   None is ambiguous (the media handler might return None).
-                        if resp._media_rendered is _UNSET:
+                        if resp._media_rendered is MISSING:
                             opt = resp.options
                             if not resp.content_type:
                                 resp.content_type = opt.default_media_type
@@ -577,7 +577,7 @@ async def __call__(  # type: ignore[override] # noqa: C901
                         data = text.encode()
                     except AttributeError:
                         # NOTE(kgriffs): Assume it was a bytes object already
-                        data = text
+                        data = text  # type: ignore[assignment]
 
             else:
                 # NOTE(vytas): Custom response type.
@@ -1028,9 +1028,9 @@ def _schedule_callbacks(self, resp: Response) -> None:
 
         loop = asyncio.get_running_loop()
 
-        for cb, is_async in callbacks:  # type: ignore[attr-defined]
+        for cb, is_async in callbacks or ():
             if is_async:
-                loop.create_task(cb())
+                loop.create_task(cb())  # type: ignore[arg-type]
             else:
                 loop.run_in_executor(None, cb)