import base64

import json

from typing import List

from typing import Union

Command = Union[str, List[str]]

def encode(obj: Command) -> str:

"""

Encode a string in a shell-safe way.

The resulting string is a representation of a python value that is:

* json encoded, then

* utf-8 encoded, then

* base64 encoded.

"""

# here we encode the command to a shell-safe value:

# [ "echo", "hello" ] # python ->

# '[ "echo", "hello" ]' # JSON encoded ->

# b'[ "echo", "hello" ]' # JSON encoded, utf-8 encoded bytes ->

# b'WyJlY2hvIiwgImhlbGxvIl0=' # base64 encoded bytes ->

# 'WyJlY2hvIiwgImhlbGxvIl0=' # ascii representation of the encoded bytes

safe = base64.b64encode(json.dumps(obj).encode("utf-8"))

return safe.decode("ascii")

def decode(s: str) -> Command:

"""

Decode a string that was encoded in a shell-safe way.

The string is a representation of a python value that was:

* json encoded, then

* utf-8 encoded, then

* base64 encoded.

"""

return json.loads(base64.b64decode(s.encode("ascii")))