login.py

# -*- coding: utf-8 -*-
#
# LOGIN.PY -- Gère l'interface d'authentification à l'aide des modèles Django.
#
# Copyright (C) 2009-2010 Nicolas Dandrimont
# Authors: Nicolas Dandrimont <olasd@crans.org>
# Censor: Antoine Durand-Gasselin <adg@crans.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.


import ldap
from django.contrib.auth.models import Group, User, Permission
from django.contrib.auth.backends import ModelBackend
from django.views.decorators.debug import sensitive_variables
from django.contrib.contenttypes.models import ContentType

# Pour se connecter à la base ldap
import lc_ldap.shortcuts

from intranet import conn_pool, settings

GROUPES_SPECIAUX = { # Dictionnaire de groupe spéciaux à attribuer selon le test correspondant
"crans_paiement_ok": lambda u: u.paiement_ok(),
"crans_imprimeur_club": lambda u: u.imprimeur_clubs(),
"crans_respo_club": lambda u: u.clubs(),
"crans_adherent": lambda u: 'aid' in u,
"crans_club": lambda u: 'cid' in u,
}
USER_TYPE = ContentType.objects.get(app_label="auth", model="user")
CRANS_MULTIMACHINES,created = Permission.objects.get_or_create(codename=u"crans_multimachines",
                                       name=u"crans_multimachines",
                                       content_type=USER_TYPE)

DROITS_SPECIAUX = { # Dictionnaire de groupe devant contenir les droits correspondant
"crans_cableur": [CRANS_MULTIMACHINES],
"crans_imprimeur": [CRANS_MULTIMACHINES],
"crans_apprenti": [CRANS_MULTIMACHINES],
"crans_bureau": [CRANS_MULTIMACHINES],
"crans_ma": [CRANS_MULTIMACHINES],
}


def get_or_create_cransgroup(name):
    """ Crée le groupe crans_name avec le droit crans_name.
    """
    group, created = Group.objects.get_or_create(name=name)
    if created:
        permission,created = Permission.objects.get_or_create(codename=name,
                                       name=name,
                                       content_type=USER_TYPE)
        group.permissions.add(permission)
	if name in DROITS_SPECIAUX:
		group.permissions.add(*DROITS_SPECIAUX[name])
        group.save()
    return group

def refresh_droits(user, cl_user, allow_staff=False):
    """Rafraîchit les droits de l'utilisateur django `user' depuis
    l'utilisateur LDAP `cl_user'.
    N'ajoute pas les droits crans si allow_staff=False (default)
    """

    cl_droits_reels = set(x.value for x in cl_user.get('droits', []))
    if allow_staff:
        cl_droits = cl_droits_reels
    else:
        cl_droits = set()

    # Droit membre actif générique
    if cl_droits_reels:
        cl_droits.add(u"MA")
    if cl_droits_reels and allow_staff:
        cl_droits.add(u"enabled")

    # Fais le calcul des droits d'accès
    user.is_staff = not cl_droits.isdisjoint([u"Nounou", u"Apprenti", u"Imprimeur"])
    user.is_superuser = not cl_droits.isdisjoint([u"Nounou"])

    # et celui des groupes
    groups = []
    for cl_droit in cl_droits:
        groups.append(get_or_create_cransgroup(name=u"crans_%s" % cl_droit.lower()))
    for group in GROUPES_SPECIAUX:
        if GROUPES_SPECIAUX[group](cl_user):
            groups.append(get_or_create_cransgroup(name=group))

    user.groups = [ group for group in user.groups.all() if not group.name.startswith('crans_') ]
    user.groups.add(*groups)
    user.save()

def refresh_fields(user, cl_user):
    """Rafraîchit les champs correspondants à l'utilisateur (nom,
    prénom, email)"""

    user.first_name = unicode(cl_user.get('prenom', [u"club"])[0])
    user.last_name = unicode(cl_user['nom'][0])
    mail = unicode(cl_user.get('mail', cl_user['uid'])[0])
    if '@' not in mail:  # Ne devrait pas arriver (pour migration)
        mail += u'@crans.org'
    user.email = mail

    user.save()

def post_cas_login(sender, user, created, attributes, ticket, service, **kwargs):
    ldap_user = conn_pool.get_user(user)
    refresh_droits(user, ldap_user)
    refresh_fields(user, ldap_user)

class LDAPUserBackend(ModelBackend):
    """Authentifie un utilisateur à l'aide de la base LDAP"""

    supports_anonymous_user = False

    @sensitive_variables('password')
    def authenticate(self, username=None, password=None, **kwargs):
        """Authentifie l'utilisateur sur la base LDAP. Crée un
        utilisateur django s'il n'existe pas encore."""

        if not username or not password:
            return None
        shortcut = lc_ldap.shortcuts.lc_ldap_test if settings.BASE_LDAP_TEST else lc_ldap.shortcuts.lc_ldap
        try:
            conn = shortcut(user = username, cred = password)
            myself = conn.search(dn = conn.dn, scope = ldap.SCOPE_BASE)
            ldap_user = myself[0]
        except IndexError:
            return None
        except ldap.INVALID_CREDENTIALS:
            return None

        # On stocke les utilisateurs dans la base django comme "uid@crans.org"
        django_username = '%s@crans.org' % username
        try:
            user = User.objects.get(username=django_username)
        except User.DoesNotExist:
            user = User(username=django_username, password="LDAP Backend User!")
        user.save()
        conn_pool.CONNS[django_username] = conn
        refresh_droits(user, ldap_user)
        refresh_fields(user, ldap_user)
        return user

    def get_user(self, uid):
        """Récupère l'objet django correspondant à l'uid"""
        try:
            return User.objects.get(pk=uid)
        except User.DoesNotExist:
            return None