from __future__ import unicode_literals


class TokenError(Exception):
    pass


class TokenBackendError(Exception):
    pass

from __future__ import unicode_literals

from django.utils.translation import ugettext_lazy as _
from rest_framework import exceptions, status


class TokenError(Exception):
    pass


class TokenBackendError(Exception):
    pass


class DetailDictMixin(object):
    def __init__(self, detail=None, code=None):
        """
        Builds a detail dictionary for the error to give more information to API
        users.
        """
        detail_dict = {'detail': self.default_detail, 'code': self.default_code}

        if isinstance(detail, dict):
            detail_dict.update(detail)
        elif detail is not None:
            detail_dict['detail'] = detail

        if code is not None:
            detail_dict['code'] = code

        super(DetailDictMixin, self).__init__(detail_dict)


class AuthenticationFailed(DetailDictMixin, exceptions.AuthenticationFailed):
    pass


class InvalidToken(DetailDictMixin, exceptions.APIException):
    status_code = status.HTTP_401_UNAUTHORIZED
    default_detail = _('Token is invalid or expired')
    default_code = 'token_not_valid'

Add extra exception classes