"""persistent sessions stored in big table

:organization: Logilab

:copyright: 2008-2009 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr

XXX TODO:

* cleanup persistent session

* use user as ancestor?

"""

__docformat__ = "restructuredtext en"

from pickle import loads, dumps

from time import localtime, strftime

from logilab.common.decorators import cached, clear_cache

from cubicweb import BadConnectionId

from cubicweb.dbapi import Connection, ConnectionProperties, repo_connect

from cubicweb.selectors import none_rset, match_user_groups

from cubicweb.server.session import Session

from cubicweb.web import InvalidSession

from cubicweb.web.application import AbstractSessionManager

from cubicweb.web.application import AbstractAuthenticationManager

from google.appengine.api.datastore import Key, Entity, Get, Put, Delete, Query

from google.appengine.api.datastore_errors import EntityNotFoundError

from google.appengine.api.datastore_types import Blob

try:

    del Connection.__del__

except AttributeError:

    pass # already deleted

class GAEAuthenticationManager(AbstractAuthenticationManager):

    """authenticate user associated to a request and check session validity,

    using google authentication service

    """

    def __init__(self, *args, **kwargs):

        super(GAEAuthenticationManager, self).__init__(*args, **kwargs)

        self._repo = self.config.repository(vreg=self.vreg)

    def authenticate(self, req, _login=None, _password=None):

        """authenticate user and return an established connection for this user

        :raise ExplicitLogin: if authentication is required (no authentication

        info found or wrong user/password)

        """

        if _login is not None:

            login, password = _login, _password

        else:

            login, password = req.get_authorization()

        # remove possibly cached cursor coming from closed connection

        clear_cache(req, 'cursor')

        cnxprops = ConnectionProperties(self.vreg.config.repo_method,

                                        close=False, log=False)

        cnx = repo_connect(self._repo, login, password, cnxprops=cnxprops)

        self._init_cnx(cnx, login, password)

        # associate the connection to the current request

        req.set_connection(cnx)

        return cnx

    def _init_cnx(self, cnx, login, password):

        cnx.anonymous_connection = self.config.is_anonymous_user(login)

        cnx.vreg = self.vreg

        cnx.login = login

        cnx.password = password

class GAEPersistentSessionManager(AbstractSessionManager):

    """manage session data associated to a session identifier"""

    def __init__(self, *args, **kwargs):

        super(GAEPersistentSessionManager, self).__init__(*args, **kwargs)

        self._repo = self.config.repository(vreg=self.vreg)

    def get_session(self, req, sessionid):

        """return existing session for the given session identifier"""

        # search a record for the given session

        key = Key.from_path('CubicWebSession', 'key_' + sessionid, parent=None)

        try:

            record = Get(key)

        except EntityNotFoundError:

            raise InvalidSession()

        repo = self._repo

        if self.has_expired(record):

            repo._sessions.pop(sessionid, None)

            Delete(record)

            raise InvalidSession()

        # associate it with a repository session

        try:

            reposession = repo._get_session(sessionid)

            user = reposession.user

            # touch session to avoid closing our own session when sessions are

            # cleaned (touch is done on commit/rollback on the server side, too

            # late in that case)

            reposession._touch()

        except BadConnectionId:

            # can't found session in the repository, this probably mean the

            # session is not yet initialized on this server, hijack the repo

            # to create it

            # use an internal connection

            ssession = repo.internal_session()

            # try to get a user object

            try:

                user = repo.authenticate_user(ssession, record['login'],

                                              record['password'])

            finally:

                ssession.close()

            reposession = Session(user, self._repo, _id=sessionid)

            self._repo._sessions[sessionid] = reposession

        cnx = Connection(self._repo, sessionid)

        return self._get_proxy(req, record, cnx, user)

    def open_session(self, req):

        """open and return a new session for the given request"""

        cnx = self.authmanager.authenticate(req)

        # avoid rebuilding a user

        user = self._repo._get_session(cnx.sessionid).user

        # build persistent record for session data

        record = Entity('CubicWebSession', name='key_' + cnx.sessionid)

        record['login'] = cnx.login

        record['password'] = cnx.password

        record['anonymous_connection'] = cnx.anonymous_connection

        Put(record)

        return self._get_proxy(req, record, cnx, user)

    def close_session(self, proxy):

        """close session on logout or on invalid session detected (expired out,

        corrupted...)

        """

        proxy.close()

    def current_sessions(self):

        for record in Query('CubicWebSession').Run():

            yield ConnectionProxy(record)

    def _get_proxy(self, req, record, cnx, user):

        proxy = ConnectionProxy(record, cnx, user)

        user.req = req

        req.set_connection(proxy, user)

        return proxy

class ConnectionProxy(object):

    def __init__(self, record, cnx=None, user=None):

        self.__record = record

        self.__cnx = cnx

        self.__user = user

        self.__data = None

        self.__is_dirty = False

        self.sessionid = record.key().name()[4:] # remove 'key_' prefix

    def __repr__(self):

        sstr = '<ConnectionProxy %s' % self.sessionid

        if self.anonymous_connection:

            sstr += ' (anonymous)'

        elif self.__user:

            sstr += ' for %s' % self.__user.login

        sstr += ', last used %s>' % strftime('%T', localtime(self.last_usage_time))

        return sstr

    def __getattribute__(self, name):

        try:

            return super(ConnectionProxy, self).__getattribute__(name)

        except AttributeError:

            return getattr(self.__cnx, name)

    def _set_last_usage_time(self, value):

        self.__is_dirty = True

        self.__record['last_usage_time'] = value

    def _get_last_usage_time(self):

        return self.__record['last_usage_time']

    last_usage_time = property(_get_last_usage_time, _set_last_usage_time)

    @property

    def anonymous_connection(self):

        # use get() for bw compat if sessions without anonymous information are

        # found. Set default to True to limit lifetime of those sessions.

        return self.__record.get('anonymous_connection', True)

    @property

    @cached

    def data(self):

        if self.__record.get('data') is not None:

            try:

                return loads(self.__record['data'])

            except:

                self.__is_dirty = True

                self.exception('corrupted session data for session %s',

                               self.__cnx)

        return {}

    def get_session_data(self, key, default=None, pop=False):

        """return value associated to `key` in session data"""

        if pop:

            try:

                value = self.data.pop(key)

                self.__is_dirty = True

                return value

            except KeyError:

                return default

        else:

            return self.data.get(key, default)

    def set_session_data(self, key, value):

        """set value associated to `key` in session data"""

        self.data[key] = value

        self.__is_dirty = True

    def del_session_data(self, key):

        """remove value associated to `key` in session data"""

        try:

            del self.data[key]

            self.__is_dirty = True

        except KeyError:

            pass    

    def commit(self):

        if self.__is_dirty:

            self.__save()

        self.__cnx.commit()

    def rollback(self):

        self.__save()

        self.__cnx.rollback()

    def close(self):

        if self.__cnx is not None:

            self.__cnx.close()

        Delete(self.__record)

    def __save(self):

        if self.__is_dirty:

            self.__record['data'] = Blob(dumps(self.data))

            Put(self.__record)

            self.__is_dirty = False

    def user(self, req=None, props=None):

        """return the User object associated to this connection"""

        return self.__user

import logging

from cubicweb import set_log_methods

set_log_methods(ConnectionProxy, logging.getLogger('cubicweb.web.goa.session'))

from cubicweb.common.view import StartupView

from cubicweb.web import application

class SessionsCleaner(StartupView):

    id = 'cleansessions'

    __select__ = none_rset() & match_user_groups('managers')

    def call(self):

        # clean web session

        session_manager = application.SESSION_MANAGER

        nbclosed, remaining = session_manager.clean_sessions()

        self.w(u'<div class="message">')

        self.w(u'%s web sessions closed<br/>\n' % nbclosed)

        # clean repository sessions

        repo = self.config.repository(vreg=self.vreg)

        nbclosed = repo.clean_sessions()

        self.w(u'%s repository sessions closed<br/>\n' % nbclosed)

        self.w(u'%s remaining sessions<br/>\n' % remaining)

        self.w(u'</div>')

def registration_callback(vreg):

    vreg.register(SessionsCleaner)

    vreg.register(GAEAuthenticationManager, clear=True)

    vreg.register(GAEPersistentSessionManager, clear=True)