Source code for summer.lxaop

# -*- coding: utf-8 -*-
# Time-stamp: < lxaop.py (2016-02-14 10:52) >

# Copyright (C) 2009-2016 Martin Slouf <martin.slouf@sourceforge.net>
#
# This file is a part of Summer.
#
# Summer 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 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 Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

"""Declarative LDAP session/connection management.  Analogy to
:py:mod:`summer.txaop` module.

"""

import logging
import types

from .aop import AroundMethodAdvice, Proxy
from .lsf import LdapSessionFactory
from .lx import LdapCallback, LdapWrapper

logger = logging.getLogger(__name__)


[docs]def ldapaop(func: types.FunctionType): """Method decorator marking method as transactional. Analogy to :py:func:`summer.txaop.transactional`. Use together with :py:class:`LdapAdvice` and :py:class:`LdapProxy`. Methods decorated with :py:func:`ldapaop` can be run within a LDAP session/connection if wrapped in :py:class:`LdapProxy`. Intended use case for this decorator is to decorate :py:class:`summer.ldapdao.LdapEntityDao` methods and then access current *ldap3* session/connection by using :py:attr:`summer.ldapdao.LdapDao.session` from within the *DAO* method. Thus you can access *ldap3* session/connection (and manipulate data), and still have the transaction boundaries defined on top of your business methods. Args: func (types.FunctionType): function to be decorated """ func.ldapaop = True # mame .. method name # mame = "%s.%s" % (func.im_class.__name__, func.__name__) mame = func.__name__ logger.debug("method %s decorated as ldapaop", mame) return func
[docs]class LdapAdvice(AroundMethodAdvice): """Together with :py:func:`transactional` decorator forms a *transaction aspect*. Analogy to :py:class:`summer.txaop.TransactionAdvice`. Advice gets invoked if method is marked with :py:func:`ldapaop` and if object is wrapped in :py:class:`LdapProxy`. """ class Callback(LdapCallback): def __init__(self, advice): """Creates internal :py:class:`LdapCallback` instance. Args: advice (LdapAdvice): reference to parent :py:class:`TransactionAdvice` """ self.advice = advice def lxrun(self, session: LdapSessionFactory.Local, *args, **kwargs): result = self.advice.method(*args, **kwargs) return result
[docs] def __init__(self, method: types.MethodType, ldap_session_factory: LdapSessionFactory): """Creates :py:class:`LdapAdvice` instance. Args: method (types.MethodType): instance method marked by :py:func:`ldapaop` decorator ldap_session_factory (LdapSessionFactory): ldap session factory to be used """ AroundMethodAdvice.__init__(self, method) self.ldap_session_factory = ldap_session_factory
[docs] def around(self, *args, **kwargs): """Wraps the target method invocation within a ldap session/connection. If any exception is raised it gets re-thrown, see :py:class:`summer.lx.LdapWrapper`. """ lx = LdapWrapper(self.ldap_session_factory) callback = LdapAdvice.Callback(self) try: logger.debug("lx advice start for '%s'", self.mame) result = lx.execute(callback, *args, **kwargs) logger.debug("lx advice end for '%s'", self.mame) return result except Exception as ex: logger.exception("lx advice error for '%s'", self.mame) raise ex
[docs]class LdapProxy(Proxy): """Intercepts method invocations on target object with ldap session/connection logic. It either calls the target object's method directly or invokes the :py:class:`LdapAdvice` if the method is marked by :py:func:`ldapaop`. """
[docs] def __init__(self, target: object, ldap_session_factory: LdapSessionFactory=None): """Creates the :py:class:`LdapProxy` instance. Searches the *target* object for :py:func:`ldapaop` decorated methods. It creates a :py:class:`LdapAdvice` object for each method found. Invocation of such a method means invoking a :py:class:`LdapAdvice` object instead, wrapping the call with ldap session/connection. Args: target (object): any object that is searched for ldap methods ldap_session_factory (LdapSessionFactory): ldap session factory to be used; if ``None``, *target* object is searched for ``ldap_session_factory`` attribute which is used instead """ Proxy.__init__(self, target) logger.info("creating ldap proxy for '%s'", target) if ldap_session_factory is None: self.ldap_session_factory = target.ldap_session_factory else: self.ldap_session_factory = ldap_session_factory methods = self._get_decorated_methods(ldapaop.__name__) for i in methods: advice = LdapAdvice(i, self.ldap_session_factory) setattr(self, i.__name__, advice) logger.debug("ldap advice '%s' created", advice)