Update routes.py

routes.py

@@ -108,11 +108,16 @@ def list_chats(bot_id: str):
     except Exception as e:
         raise HTTPException(status_code=500, detail=str(e))
 
+from fastapi.encoders import jsonable_encoder
+from bson import ObjectId
+
 @router.get("/chat_history/{chat_id}")
 def chat_history(chat_id: str, bot_id: str):
     trainer = get_trainer()
     try:
         history = trainer.get_chat_by_id(chat_id=chat_id)
-        return history
+        # Convert ObjectId instances to strings before returning the response.
+        return jsonable_encoder(history, custom_encoder={ObjectId: str})
     except Exception as e:
         raise HTTPException(status_code=500, detail=str(e))
+