Update InjectAutoreloadMiddleware to be compatible with starlette >= 0.35.0 (#1013)

Co-authored-by: Winston Chang <[email protected]>

Author: schloerke

shiny/_autoreload.py

@@ -8,8 +8,9 @@
 import secrets
 import threading
 import webbrowser
-from typing import Callable, Optional
+from typing import Callable, Optional, cast
 
+import starlette.types
 from asgiref.typing import (
     ASGI3Application,
     ASGIReceiveCallable,
@@ -90,8 +91,19 @@ class InjectAutoreloadMiddleware:
     because we want autoreload to be effective even when displaying an error page.
     """
 
-    def __init__(self, app: ASGI3Application):
-        self.app = app
+    def __init__(
+        self,
+        app: starlette.types.ASGIApp | ASGI3Application,
+        *args: object,
+        **kwargs: object,
+    ):
+        if len(args) > 0 or len(kwargs) > 0:
+            raise TypeError(
+                f"InjectAutoreloadMiddleware does not support positional or keyword arguments, received {args}, {kwargs}"
+            )
+        # The starlette types and the asgiref types are compatible, but we'll use the
+        # latter internally. See the note in the __call__ method for more details.
+        self.app = cast(ASGI3Application, app)
         ws_url = autoreload_url()
         self.script = (
             f"""  <script src="__shared/shiny-autoreload.js" data-ws-url="{html.escape(ws_url)}"></script>
@@ -103,19 +115,31 @@ def __init__(self, app: ASGI3Application):
         )
 
     async def __call__(
-        self, scope: Scope, receive: ASGIReceiveCallable, send: ASGISendCallable
+        self,
+        scope: starlette.types.Scope | Scope,
+        receive: starlette.types.Receive | ASGIReceiveCallable,
+        send: starlette.types.Send | ASGISendCallable,
     ) -> None:
-        if scope["type"] != "http" or scope["path"] != "/" or len(self.script) == 0:
-            return await self.app(scope, receive, send)
+        # The starlette types and the asgiref types are compatible, but the latter are
+        # more rigorous. In the call interface, we accept both types for compatibility
+        # with both. But internally we'll use the more rigorous types.
+        # See https://github.com/encode/starlette/blob/39dccd9/docs/middleware.md#type-annotations
+        scope = cast(Scope, scope)
+        receive_casted = cast(ASGIReceiveCallable, receive)
+        send_casted = cast(ASGISendCallable, send)
+        if scope["type"] != "http":
+            return await self.app(scope, receive_casted, send_casted)
+        if scope["path"] != "/" or len(self.script) == 0:
+            return await self.app(scope, receive_casted, send_casted)
 
         def mangle_callback(body: bytes) -> tuple[bytes, bool]:
             if b"</head>" in body:
                 return (body.replace(b"</head>", self.script, 1), True)
             else:
                 return (body, False)
 
-        mangler = ResponseMangler(send, mangle_callback)
-        await self.app(scope, receive, mangler.send)
+        mangler = ResponseMangler(send_casted, mangle_callback)
+        await self.app(scope, receive_casted, mangler.send)
 
 
 # PARENT PROCESS ------------------------------------------------------------