[Frontend] Improve error message (#31987)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>

vllm/entrypoints/utils.py

@@ -9,6 +9,7 @@ from argparse import Namespace
 from pathlib import Path
 from typing import Any
 
+import regex as re
 from fastapi import Request
 from fastapi.responses import JSONResponse, StreamingResponse
 from starlette.background import BackgroundTask, BackgroundTasks
@@ -317,3 +318,8 @@ async def process_chat_template(
                     model_config.model,
                 )
     return resolved_chat_template
+
+
+def sanitize_message(message: str) -> str:
+    # Avoid leaking memory address from object reprs
+    return re.sub(r" at 0x[0-9a-f]+>", ">", message)