[CWEP002] introduce RQLRelationRewriter
Refactor existing RQLRewriter for later reuse of rewriting relation as specified
by CWEP002. Work is different because we simply want to replace a relation by
another rql snippet and we don't have to bother with EXISTS, subqueries and all.
This rewriter is not yet plugged into the querier.
Depends on yams 0.40 API.
Related to #3546717
# copyright 2003-2011 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.
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# You should have received a copy of the GNU Lesser General Public License along
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"""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)