models.py 文件源码

def load_token(token):
    """
    Flask-Login token_loader callback.
    The token_loader function asks this function to take the token that was
    stored on the users computer process it to check if its valid and then
    return a User Object if its valid or None if its not valid.

    :param token: Token generated by :meth:`app.models.User.get_auth_token`
    """

    # The Token itself was generated by User.get_auth_token.  So it is up to
    # us to known the format of the token data itself.

    # The Token was encrypted using itsdangerous.URLSafeTimedSerializer which
    # allows us to have a max_age on the token itself.  When the cookie is
    # stored
    # on the users computer it also has a exipry date, but could be changed by
    # the user, so this feature allows us to enforce the exipry date of the
    # token
    # server side and not rely on the users cookie to exipre.

    max_age = current_app.config['REMEMBER_COOKIE_DURATION'].total_seconds()

    # Decrypt the Security Token, data = [username, hashpass, id]
    s = URLSafeTimedSerializer(
        current_app.config['SECRET_KEY'],
        salt='user-auth',
        signer_kwargs=dict(key_derivation='hmac',
                           digest_method=hashlib.sha256))
    try:
        data = s.loads(token, max_age=max_age)
    except (BadTimeSignature, SignatureExpired):
        return None

    # Find the User
    user = User.query.get(data[2])

    # 2FA check
    totp_endpoint = request.endpoint == 'auth.verify_totp'
    if user and user.otp_enabled and not totp_endpoint and len(data) < 4:
        return None

    # Check Password and return user or None
    if user and data[1] == user._password:
        return user
    return None