fix app.py

app.py

@@ -22,11 +22,11 @@ if not os.path.exists(CACHE_DIR):
 if not os.path.exists(INDEX_FILE):
     raise FileNotFoundError(f"{INDEX_FILE} not found. Please make sure the file exists.")
 
-indexer()
-
 with open(INDEX_FILE, 'r') as f:
     file_structure = json.load(f)
 
+indexer()
+
 def prefetch_metadata():
     for item in file_structure:
         if 'contents' in item: