add routes and upload functions

my_modules/file_helper_functions.py

@@ -0,0 +1,33 @@
+from my_modules.app.constens import SECRET_KEY
+
+import hmac, hashlib, base64, secrets, time
+from urllib.parse import quote, unquote
+
+def base64url_encode(data: bytes) -> str:
+  return base64.urlsafe_b64encode(data).decode().rstrip("=")
+
+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_signed_url(file_id: str) -> str:
+  # signature based only on the file_id
+  sig = hmac.new(SECRET_KEY, file_id.encode(), hashlib.sha256).digest()
+  token = base64url_encode(sig)
+  return f"-{file_id}?sig={token}"
+
+def verify_signed_url(file_id: str, token: str, file_expiration: int) -> bool:
+  # check both the signature and the file's stored expiration time
+  expected_sig = hmac.new(SECRET_KEY, file_id.encode(), hashlib.sha256).digest()
+  valid_sig = hmac.compare_digest(base64url_encode(expected_sig), token)
+  not_expired = file_expiration >= time.time()
+  return valid_sig and not_expired
+
+if __name__ == "__main__":
+  file_id = generate_short_id()
+  url = generate_signed_url(file_id)
+  print(url)