"""

Special authentifiers.

:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses

"""

__docformat__ = "restructuredtext en"

from cubicweb import AuthenticationError

from cubicweb.server.sources import native

class Token(object):

    pass

EXT_TOKEN = Token()

class DirectAuthentifier(native.BaseAuthentifier):

    """return CWUser eid for the given login.

    Before doing so, it makes sure the authentication request comes from

    xxx by checking the special '__externalauth_directauth' kwarg.

    """

    auth_rql = (

        'Any U WHERE U is CWUser, '

        'U eid %(eid)s'

    )

    def authenticate(self, session, login, **kwargs):

        """Return the CWUser eid for the given login.

        Make sure the request comes from inside pyramid by

        checking the special '__pyramid_directauth' kwarg.

        """

        session.debug('authentication by %s', self.__class__.__name__)

        directauth = kwargs.get('__pyramid_directauth', None)

        try:

            if directauth == EXT_TOKEN:

                rset = session.execute(self.auth_rql, {'eid': int(login)})

                if rset:

                    session.debug('Successfully identified %s', login)

                    return rset[0][0]

        except Exception, exc:

            session.debug('authentication failure (%s)', exc)

        raise AuthenticationError('user is not registered')