JSON Web token in python

auth_token.py

from itsdangerous import (
    TimedJSONWebSignatureSerializer as TokenSerializer,
    BadSignature, SignatureExpired
)

class AuthToken(object):
    """AuthToken class"""

    SECRET_KEY = 'secret-key'

    @classmethod
    def generate(cls, payload, expires_in=3600, salt=b'auth-token-salt'):
        """Generate token
        Returns a token string
        :param payload: data to attach with token
        :param expires_in: validity of token in seconds
        :param salt: salt string for token
        """
        s = TokenSerializer(cls.SECRET_KEY, expires_in=expires_in)
        return s.dumps(payload, salt=salt)

    @classmethod
    def verify(cls, token, salt=b'auth-token-salt'):
        """Verify token
        Returns a tuple containing verify result and payload
        :param token: token string to verify
        :param salt: salt string for token
        """
        s = TokenSerializer(cls.SECRET_KEY)
        try:
            payload = s.loads(token, salt=salt)
        except SignatureExpired as e:
            # expired token
            return False, e.payload
        except BadSignature:
            # invalid token
            return None, None
        # valid token
        return True, payload

    @classmethod
    def set_secret_key(cls, secret_key):
        """Set secret key
        Returns AuthToken class
        :param secret_key: secret key string
        """
        cls.SECRET_KEY = secret_key
        return cls

example.py

from auth_token import AuthToken

validity = 3600 # 1 hour

token = AuthToken.generate({'user_id': 45}, validity)

token_valid, token_data = AuthToken.verify(token)

if token_valid is None:
    # token invalid
elif token_valid is False:
    # token expired
    # token_data['user_id'] == 45
else:
    # token valid
    # token_data['user_id'] == 45