Empty _REQ_TYPES_WITH_OPAQUE_FIELDS on the msgpack IPC path (#29465 Task 4) (#30182)

python/sglang/srt/entrypoints/http_server.py

@@ -797,6 +797,11 @@ if os.environ.get("DUMPER_SERVER_PORT") == "reuse":
     async def _dumper_control_handler(method: str, request: Request):
         body_bytes = await request.body()
         body = await request.json() if body_bytes else {}
+        if not isinstance(body, dict):
+            return ORJSONResponse(
+                status_code=400,
+                content={"error": "Request body must be a JSON object."},
+            )
         obj = DumperControlReqInput(method=method, body=body)
         results = await _global_state.tokenizer_manager.dumper_control(obj)
         if any(not r.success for r in results):