Fix CustomStaticResource with aiohttp 3.10+ (#689)

Author: bdraco

aiohttp_devtools/runserver/serve.py

@@ -397,23 +397,49 @@ def _insert_footer(self, response: web.StreamResponse) -> web.StreamResponse:
         resp.last_modified = filepath.stat().st_mtime  # type: ignore[assignment]
         return resp
 
+    def _insert_footer_if_exists(
+        self, filename: str, response: web.StreamResponse
+    ) -> web.StreamResponse:
+        """Insert the footer if the file exists, otherwise return a 404 response."""
+        resolved_path = self._directory.joinpath(filename).resolve()
+        if not resolved_path.is_file():
+            return self._make_not_found_response(resolved_path)
+        return self._insert_footer(response)
+
+    def _make_not_found_response(self, raw_path: Path) -> web.StreamResponse:
+        """Create a 404 response with a list of available files under the requested path."""
+        while not raw_path.is_dir():
+            raw_path = raw_path.parent
+        paths = "\n".join(
+            " {}{}".format(p.relative_to(self._directory), "/" if p.is_dir() else "")
+            for p in raw_path.iterdir()
+        )
+        msg = "404: Not Found\n\nAvailable files under '{}/':\n{}\n".format(
+            raw_path.relative_to(self._directory), paths
+        )
+        return web.Response(text=msg, status=404, content_type="text/plain")
+
     async def _handle(self, request: web.Request) -> web.StreamResponse:
-        raw_path = self.modify_request(request)
+        loop = asyncio.get_running_loop()
+        raw_path = await loop.run_in_executor(None, self.modify_request, request)
         try:
             response = await super()._handle(request)
         except HTTPNotFound:
-            while not raw_path.is_dir():
-                raw_path = raw_path.parent
-            paths = "\n".join(
-                " {}{}".format(p.relative_to(self._directory), "/" if p.is_dir() else "")
-                for p in raw_path.iterdir())
-            msg = "404: Not Found\n\nAvailable files under '{}/':\n{}\n".format(
-                raw_path.relative_to(self._directory), paths)
-            response = web.Response(text=msg, status=404, content_type="text/plain")
+            response = await loop.run_in_executor(
+                None, self._make_not_found_response, raw_path
+            )
         else:
-            response = self._insert_footer(response)
+            # With aiohttp 3.10+, we need to also check if the file actually
+            # exists since the base class does not check this anymore as its
+            # done in the response to enable handling various compressed files.
+            response = await loop.run_in_executor(
+                None,
+                self._insert_footer_if_exists,
+                request.match_info["filename"],
+                response,
+            )
             # Inject CORS headers to allow webfonts to load correctly
-            response.headers['Access-Control-Allow-Origin'] = '*'
+            response.headers["Access-Control-Allow-Origin"] = "*"
 
         if not self._browser_cache:
             # Add no-cache header to avoid browser caching in local development.