crypto.py
author Sylvain Thénault <sylvain.thenault@logilab.fr>
Thu, 19 May 2011 10:53:17 +0200
changeset 7399 972ed1843bd8
parent 5424 8ecbcbff9777
child 7879 9aae456abab5
permissions -rw-r--r--
[multi-sources] support for moving an entity from an external source (closes #343818) Original need is to move a user from a ldap source to the system source so we can delete it from ldap without loosing information into the cubicweb instance. We can't wait for the user to be deleted from the ldap since it will be too late then to get back user attributes, so it has to be a manual operation to operate before actual deletion. This makes sense for other sources as well. So the idea is to make the "Any cw_source CWSource" relation editable by managers, and to watch changes of it. We then check the move is possible (ie from an external source to the system source) and do necessary stuff (essentially changing source information and copying data into the system source). Remaining pb is that we don't want the moved entity to be reimported later. To distinguish this state, the trick is to change the associated record in the 'entities' system table with eid=-eid while leaving other fields unchanged, and to add a new record with eid=eid, source='system'. External source will then have consider case where `extid2eid` return a negative eid as 'this entity was known but has been moved, ignore it'. Notice no ui is provided yet, it has currently to be done in a c-c shell.

# copyright 2003-2010 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb is free software: you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option)
# any later version.
#
# CubicWeb is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
"""Simple cryptographic routines, based on python-crypto.

"""
__docformat__ = "restructuredtext en"

from pickle import dumps, loads
from base64 import b64encode, b64decode

from Crypto.Cipher import Blowfish


_CYPHERERS = {}
def _cypherer(seed):
    try:
        return _CYPHERERS[seed]
    except KeyError:
        _CYPHERERS[seed] = Blowfish.new(seed, Blowfish.MODE_ECB)
        return _CYPHERERS[seed]


def encrypt(data, seed):
    string = dumps(data)
    string = string + '*' * (8 - len(string) % 8)
    string = b64encode(_cypherer(seed).encrypt(string))
    return unicode(string)


def decrypt(string, seed):
    # pickle ignores trailing characters so we do not need to strip them off
    string = _cypherer(seed).decrypt(b64decode(string))
    return loads(string)