crypto.py
author Alexandre Fayolle <alexandre.fayolle@logilab.fr>
Thu, 21 Apr 2011 16:33:55 +0200
branchstable
changeset 7341 c419c2d0d13e
parent 5424 8ecbcbff9777
child 7879 9aae456abab5
permissions -rw-r--r--
add a new method iter_process_result which does the same as proces_result but is a generator (closes #1625374) process_result is reimplemented using the new method, and the two helper methods are turned into generators. These generators use cursor.fetchmany instead of cursor.fetchall after setting cursor.arraysize to 100. This means that the whole result set should never loaded in memory when using the iter_process_result method. This is used in the "portable" database dump implementation when we typically to 'SELECT * FROM table', but could probably be used too in other parts of cubicweb.

# 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)