def gen_chk(cls, type: str, values: List[Union[int, str]]) -> str:
"""Generates a "chk" value, used in different requests to GD servers.
The method is: combine_values -> add salt -> sha1 hash
-> XOR -> Base64 encode -> return
Parameters
----------
type: :class:`str`
String representation of type, e.g. ``'comment'``.
Used to define salt and XOR key.
values: List[Union[:class:`int`, :class:`str`]]
List of values to generate a chk with.
Returns
-------
:class:`str`
Generated ``'chk'``, represented as string.
"""
salt = cls.salts.get(type, "") # get salt
values.append(salt)
string = "".join(map(str, values))
# sha1 hash
hashed = hashlib.sha1(string.encode()).hexdigest()
# XOR
xored = XOR.cipher(key=cls.keys[type], string=hashed)
# Base64
final = cls.do_base64(xored, encode=True)
return final
def encode(cls, type: str, string: str) -> str:
"""Encodes a string, combining XOR and Base64 encode methods.
Used in different aspects of gd.py.
Parameters
----------
type: :class:`str`
String representation of type, e.g. ``'levelpass'``.
Used to define a XOR key.
string: :class:`str`
String to encode.
Returns
-------
:class:`str`
Encoded string.
"""
ciphered = XOR.cipher(key=cls.keys[type], string=string)
encoded = cls.do_base64(ciphered, encode=True)
return encoded
def decode(cls, type: str, string: str, use_bytes: bool = False) -> str:
"""Decodes a XOR -> Base64 ciphered string.
.. note::
Due to the fact that decode and encode work almost the same,
the following is true:
.. code-block:: python3
Coder.decode('message', Coder.encode('message', 'NeKit')) == 'NeKit' # True
Parameters
----------
type: :class:`str`
String representation of a type, e.g. ``'level'``.
Used to define a XOR key.
string: :class:`str`
String to decode.
Returns
-------
:class:`str`
Decoded string.
"""
string += "=" * (4 - len(string) % 4) # add padding
try:
cipher_stream = urlsafe_b64decode(string.encode())
except Exception:
return string
if use_bytes:
return XOR.cipher_bytes(key=cls.keys[type], stream=cipher_stream)
else:
return XOR.cipher(key=cls.keys[type],
string=cipher_stream.decode(errors="ignore"))