generate longer file_ids and retry if they is a collison in the database

my_modules/file_helper_functions.py

@@ -1,6 +1,6 @@
 from my_modules.app.constens import SECRET_KEY
 
-import hmac, hashlib, base64, secrets, time
+import hmac, hashlib, base64, secrets, string, time
 from datetime import datetime, timezone
 
 def base64url_encode(data: bytes) -> str:
@@ -10,9 +10,12 @@ def base64url_decode(data: str) -> bytes:
   padding = '=' * (-len(data) % 4)
   return base64.urlsafe_b64decode(data + padding)
 
-def generate_short_id(length=8):
-  token = base64.urlsafe_b64encode(secrets.token_bytes(length)).decode('utf-8')
-  return token.replace('=', '').replace('-', '').replace('_', '')[:length]
+def generate_short_id(length=11):
+  alphabet = string.ascii_letters + string.digits + '_-'
+  while True:
+    token = ''.join(secrets.choice(alphabet) for _ in range(length))
+    if not token.startswith('-'):
+      return token
 
 def generate_signed_url(file_id: str) -> str:
   # signature based only on the file_id