Update app.py

app.py

@@ -3,7 +3,7 @@ Maria AI Tutor — FastAPI Backend
 Hugging Face Spaces (Docker)
 """
 
-import os, io, re, json, base64, logging, wave, struct, urllib.request
+import os, io, re, json, base64, logging, wave, struct, urllib.request, urllib.parse
 from contextlib import asynccontextmanager
 from typing import Optional, List, Dict, Any
 
@@ -258,7 +258,7 @@ def _ensure_faiss(board: str, cls: str, subject: str):
     if key in _faiss:
         return _faiss[key], _meta[key]
     try:
-        base    = f"{DATASET_BASE_URL}/knowledgebase/{board}/{cls}/{subject}"
+        base    = "{}/knowledgebase/{}/{}/{}".format(DATASET_BASE_URL, urllib.parse.quote(board, safe=""), urllib.parse.quote(cls, safe=""), urllib.parse.quote(subject, safe=""))
         headers = {"Authorization": f"Bearer {HF_TOKEN}"} if HF_TOKEN else {}
 
         def _download(url: str, dest: str):
@@ -698,4 +698,4 @@ async def chatmessenger(request: Request, body: ChatRequest):
         raise HTTPException(status_code=403, detail="Authentication required")
 
     result = process(body)
-    return result.model_dump(by_alias=True)
+    return result.model_dump(by_alias=True)