crypto.py
author Julien Cristau <julien.cristau@logilab.fr>
Thu, 10 Dec 2015 16:58:45 +0100
changeset 10997 da712d3f0601
parent 10602 4845012cfc8e
permissions -rw-r--r--
Bring back the separate web-side entity cache Prior to changeset 635cfac73d28 "[repoapi] fold ClientConnection into Connection", we had two entity caches: one on the client/dbapi/web side, and one on the server/repo side. This is a waste, but it is actually needed as long as we have the magic _cw attribute on entities which must sometimes be a request and sometimes a cnx. Removing the duplication caused weird problems with entity._cw alternating between both types of objects, which is unexpected by both the repo and the web sides. We add an entity cache on ConnectionCubicWebRequestBase, separate from the Connection's, and bring back the _cw_update_attr_cache/dont-cache-attrs mechanism, to let the server/edition code let caches know which attributes have been modified Entity.as_rset can be cached again, as ResultSet no longer modifies the entity when fetching it from a cache. Contrary to the pre-3.21 code, _cw_update_attr_cache now handles web requests and connections in the same way (otherwise the cache ends up with wrong values if a hook modifies attributes), but dont-cache-attrs is never set for (inlined) relations. Closes #6863543

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"""Simple cryptographic routines, based on python-crypto."""
__docformat__ = "restructuredtext en"

from base64 import b64encode, b64decode

from six.moves import cPickle as pickle

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 = pickle.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 pickle.loads(string)