将字符串转换为字节

Question

I have a file that have this format:

username password (base64 encoded) id

I have to read this password (base64 encoded) and decode it to pass as a paramater in the password to authenticate. The problem is, when I read this password it is being readed as string and I get an error when I try to decode because this is expecting to be bytes.

def getSecret(self):
    home = expanduser("~/.user/credentials")
    with open(home,"r") as file:
        self.password = list(file)[1]
        self.password = base64.b64decode(self.password)

        return self.password


conn = User()
decode = base64.b64decode(conn.getSecret())
print(decode)

But this is returning a string and should be bytes, when I try to decode this i got this error

return binascii.a2b_base64(s)
binascii.Error: Incorrect padding

How can I read and decode this?

Thank you.

Answer 1

You have a Python string that you want to decode:

>>> password_b64='c2VjcmV0\n'

The binascii.a2b_base64 function will do that ( NOTE: a2b ):

>>> binascii.a2b_base64(password_b64)
b'secret'

But it returns a bytes object, not a string object. So you have to decode the bytes somehow. The obvious way is to presume they are UTF-8, and invoke the .decode(encoding) method on the resulting bytes :

>>> binascii.a2b_base64(password_b64).decode("utf-8")
'secret'

Answer 2

I found the problem, just had to remove the b'' from the string and everything worked. Thank you very much everyone.