Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/itsdangerous/encoding.py: 54%

1from __future__ import annotations 

2 

3import base64 

4import string 

5import struct 

6import typing as t 

7 

8from .exc import BadData 

9 

10 

11def want_bytes( 

12 s: str | bytes, encoding: str = "utf-8", errors: str = "strict" 

13) -> bytes: 

14 if isinstance(s, str): 

15 s = s.encode(encoding, errors) 

16 

17 return s 

18 

19 

20def base64_encode(string: str | bytes) -> bytes: 

21 """Base64 encode a string of bytes or text. The resulting bytes are 

22 safe to use in URLs. 

23 """ 

24 string = want_bytes(string) 

25 return base64.urlsafe_b64encode(string).rstrip(b"=") 

26 

27 

28def base64_decode(string: str | bytes) -> bytes: 

29 """Base64 decode a URL-safe string of bytes or text. The result is 

30 bytes. 

31 """ 

32 string = want_bytes(string, encoding="ascii", errors="ignore") 

33 string += b"=" * (-len(string) % 4) 

34 

35 try: 

36 return base64.urlsafe_b64decode(string) 

37 except (TypeError, ValueError) as e: 

38 raise BadData("Invalid base64-encoded data") from e 

39 

40 

41# The alphabet used by base64.urlsafe_* 

42_base64_alphabet = f"{string.ascii_letters}{string.digits}-_=".encode("ascii") 

43 

44_int64_struct = struct.Struct(">Q") 

45_int_to_bytes = _int64_struct.pack 

46_bytes_to_int = t.cast("t.Callable[[bytes], tuple[int]]", _int64_struct.unpack) 

47 

48 

49def int_to_bytes(num: int) -> bytes: 

50 return _int_to_bytes(num).lstrip(b"\x00") 

51 

52 

53def bytes_to_int(bytestr: bytes) -> int: 

54 return _bytes_to_int(bytestr.rjust(8, b"\x00"))[0]