Add ResponderOrResource and Action types

falcon/hooks.py

@@ -33,14 +33,15 @@
     r'^on_({})(_\w+)?$'.format('|'.join(method.lower() for method in COMBINED_METHODS))
 )
 
-SynchronousResource = t.Callable[..., t.Any]
-AsynchronousResource = t.Callable[..., t.Awaitable[t.Any]]
-Resource = t.Union[SynchronousResource, AsynchronousResource]
+Resource = object
+Responder = t.Callable
+ResponderOrResource = t.Union[Responder, Resource]
+Action = t.Callable
 
 
 def before(
-    action: Resource, *args: t.Any, is_async: bool = False, **kwargs: t.Any
-) -> t.Callable[[Resource], Resource]:
+    action: Action, *args: t.Any, is_async: bool = False, **kwargs: t.Any
+) -> t.Callable[[ResponderOrResource], ResponderOrResource]:
     """Execute the given action function *before* the responder.
 
     The `params` argument that is passed to the hook
@@ -90,7 +91,7 @@ def do_something(req, resp, resource, params):
             *action*.
     """
 
-    def _before(responder_or_resource: Resource) -> Resource:
+    def _before(responder_or_resource: ResponderOrResource) -> ResponderOrResource:
         if isinstance(responder_or_resource, type):
             resource = responder_or_resource
 
@@ -100,7 +101,9 @@ def _before(responder_or_resource: Resource) -> Resource:
                     # responder in the do_before_all closure; otherwise, they
                     # will capture the same responder variable that is shared
                     # between iterations of the for loop, above.
-                    def let(responder: Resource = responder) -> None:
+                    responder = t.cast(Responder, responder)
+
+                    def let(responder: Responder = responder) -> None:
                         do_before_all = _wrap_with_before(
                             responder, action, args, kwargs, is_async
                         )
@@ -112,7 +115,7 @@ def let(responder: Resource = responder) -> None:
             return resource
 
         else:
-            responder = responder_or_resource
+            responder = t.cast(Responder, responder_or_resource)
             do_before_one = _wrap_with_before(responder, action, args, kwargs, is_async)
 
             return do_before_one
@@ -121,8 +124,8 @@ def let(responder: Resource = responder) -> None:
 
 
 def after(
-    action: Resource, *args: t.Any, is_async: bool = False, **kwargs: t.Any
-) -> t.Callable[[Resource], Resource]:
+    action: Action, *args: t.Any, is_async: bool = False, **kwargs: t.Any
+) -> t.Callable[[ResponderOrResource], ResponderOrResource]:
     """Execute the given action function *after* the responder.
 
     Args:
@@ -155,14 +158,15 @@ def after(
             *action*.
     """
 
-    def _after(responder_or_resource: Resource) -> Resource:
+    def _after(responder_or_resource: ResponderOrResource) -> ResponderOrResource:
         if isinstance(responder_or_resource, type):
-            resource = responder_or_resource
+            resource = t.cast(Resource, responder_or_resource)
 
             for responder_name, responder in getmembers(resource, callable):
                 if _DECORABLE_METHOD_NAME.match(responder_name):
+                    responder = t.cast(Responder, responder)
 
-                    def let(responder: Resource = responder) -> None:
+                    def let(responder: Responder = responder) -> None:
                         do_after_all = _wrap_with_after(
                             responder, action, args, kwargs, is_async
                         )
@@ -174,7 +178,7 @@ def let(responder: Resource = responder) -> None:
             return resource
 
         else:
-            responder = responder_or_resource
+            responder = t.cast(Responder, responder_or_resource)
             do_after_one = _wrap_with_after(responder, action, args, kwargs, is_async)
 
             return do_after_one
@@ -188,12 +192,12 @@ def let(responder: Resource = responder) -> None:
 
 
 def _wrap_with_after(
-    responder: Resource,
-    action: Resource,
+    responder: Responder,
+    action: Action,
     action_args: t.Any,
     action_kwargs: t.Any,
     is_async: bool,
-) -> Resource:
+) -> Responder:
     """Execute the given action function after a responder method.
 
     Args:
@@ -222,7 +226,7 @@ def _wrap_with_after(
 
         @wraps(responder)
         async def do_after(
-            self: Resource,
+            self: ResponderOrResource,
             req: asgi.Request,
             resp: asgi.Response,
             *args: t.Any,
@@ -239,7 +243,7 @@ async def do_after(
 
         @wraps(responder)
         def do_after(
-            self: Resource,
+            self: ResponderOrResource,
             req: wsgi.Request,
             resp: wsgi.Response,
             *args: t.Any,
@@ -255,8 +259,8 @@ def do_after(
 
 
 def _wrap_with_before(
-    responder: Resource,
-    action: Resource,
+    responder: Responder,
+    action: Action,
     action_args: t.Tuple[t.Any, ...],
     action_kwargs: t.Dict[str, t.Any],
     is_async: bool,
@@ -289,7 +293,7 @@ def _wrap_with_before(
 
         @wraps(responder)
         async def do_before(
-            self: Resource,
+            self: ResponderOrResource,
             req: asgi.Request,
             resp: asgi.Response,
             *args: t.Any,
@@ -306,7 +310,7 @@ async def do_before(
 
         @wraps(responder)
         def do_before(
-            self: Resource,
+            self: ResponderOrResource,
             req: wsgi.Request,
             resp: wsgi.Response,
             *args: t.Any,