utility script i made that lets you turn strings into fernet keys, generate string-fernet keys, and encrypt/decrypt data with the default key (`AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA`), all from a CLI

fernet-string.py

import warnings
import argparse

from cryptography.fernet import Fernet
from secrets import token_urlsafe
from base64 import urlsafe_b64encode
from pathlib import Path

__file_path__ = Path(__file__).resolve()
__pwd__ = __file_path__.parent
save_path = __pwd__ / "faretek's fernet-string.py key.txt"

_key = save_path.read_text() if save_path.exists() else 'A' * 32

def str_2_key(gen: str) -> bytes:
    if (length := len(gen)) < 32:
        warnings.warn(f"Short key length {length}")
        gen = gen.zfill(32)
    elif length > 32:
        warnings.warn(f"Long key length {length}")
        gen = gen[:32]

    return urlsafe_b64encode(gen.encode())


fernet = Fernet(str_2_key(_key))


def main():
    class Args(argparse.Namespace):
        command: str
        content: str
        native: bool

    parser = argparse.ArgumentParser(epilog=f"KEY={_key!r}")

    if command := parser.add_subparsers(dest="command"):
        if encrypt := command.add_parser("e", help="encrypt"):
            encrypt.add_argument("content")
        if decrypt := command.add_parser("d", help="decrypt"):
            decrypt.add_argument("content")
        if gen := command.add_parser("g", help="generate key"):
            ...
        if set_key := command.add_parser("s", help="set key"):
            set_key.add_argument("content", help="new key")

    args = parser.parse_args(namespace=Args())

    match args.command:
        case "e":
            print(fernet.encrypt(args.content.encode()).decode())
        case "d":
            print(fernet.decrypt(args.content.encode()).decode())
        case "g":
            print(token_urlsafe(32))
        case "s":
            print(f"Replacing {_key!r} with {args.content!r}")
            save_path.write_text(args.content)
        case _:
            parser.print_help()


if __name__ == "__main__":
    main()

i may be obsessed with argparse

This should be changed for clarity:
fernet.generate_key() -> Fernet.generate_key()
The return type of gen_keystr could be str or bytes, which should be changed. I recommend just using secrets.token_urlsafe(32)[:32], which always produces a csprng generated string of base64urlsafe of length 32. (The random module normally produces random numbers which can be predicted)
I would also recommend making it so that the key can be changed via a cli argument.

oops, didnt notice the keystr thibg

ill do that, ok

you should use secrets.token_urlsafe for secure pseudorandomness

i implemented that in the version i put in scratchattach. I also have a separate updated version somewhere which uses secrets too. I will update this gist then