view frontends/src/bridge/DBus.py @ 1316:8adcdf2cdfe1 frontends_multi_profiles

core: added a "profileConnecting" method check: if a plugin has a profileConnecting method, it will be called when the profile is being connected but before the client stream is started. That can be usefull if things need to be done before the communication is started: e.g. putting triggers, loading PersistentDict, etc.
author Goffi <goffi@goffi.org>
date Mon, 09 Feb 2015 21:39:51 +0100
parents bb9c32249778
children 069ad98b360d
line wrap: on
line source

#!/usr/bin/python
#-*- coding: utf-8 -*-

# SAT communication bridge
# Copyright (C) 2009, 2010, 2011, 2012, 2013, 2014 Jérôme Poisson (goffi@goffi.org)

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero 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 Affero General Public License for more details.

# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from sat.core.i18n import _
from bridge_frontend import BridgeFrontend, BridgeException
import dbus
from sat.core.log import getLogger
log = getLogger(__name__)
from sat.core.exceptions import BridgeExceptionNoService, BridgeInitError

from dbus.mainloop.glib import DBusGMainLoop
DBusGMainLoop(set_as_default=True)

import ast

const_INT_PREFIX = "org.goffi.SAT"  # Interface prefix
const_ERROR_PREFIX = const_INT_PREFIX + ".error"
const_OBJ_PATH = '/org/goffi/SAT/bridge'
const_CORE_SUFFIX = ".core"
const_PLUGIN_SUFFIX = ".plugin"
const_TIMEOUT = 120


def dbus_to_bridge_exception(dbus_e):
    """Convert a DBusException to a BridgeException.

    @param dbus_e (DBusException)
    @return: BridgeException
    """
    full_name = dbus_e.get_dbus_name()
    if full_name.startswith(const_ERROR_PREFIX):
        name = dbus_e.get_dbus_name()[len(const_ERROR_PREFIX) + 1:]
    else:
        name = full_name
    # XXX: dbus_e.args doesn't contain the original DBusException args, but we
    # receive its serialized form in dbus_e.args[0]. From that we can rebuild
    # the original arguments list thanks to ast.literal_eval (secure eval).
    message = dbus_e.get_dbus_message()  # similar to dbus_e.args[0]
    try:
        message, condition = ast.literal_eval(message)
    except (SyntaxError, ValueError, TypeError):
        condition = ''
    return BridgeException(name, message, condition)


class DBusBridgeFrontend(BridgeFrontend):
    def __init__(self):
        try:
            self.sessions_bus = dbus.SessionBus()
            self.db_object = self.sessions_bus.get_object(const_INT_PREFIX,
                                                          const_OBJ_PATH)
            self.db_core_iface = dbus.Interface(self.db_object,
                                                dbus_interface=const_INT_PREFIX + const_CORE_SUFFIX)
            self.db_plugin_iface = dbus.Interface(self.db_object,
                                                  dbus_interface=const_INT_PREFIX + const_PLUGIN_SUFFIX)
        except dbus.exceptions.DBusException, e:
            if e._dbus_error_name == 'org.freedesktop.DBus.Error.ServiceUnknown':
                raise BridgeExceptionNoService
            elif e._dbus_error_name == 'org.freedesktop.DBus.Error.NotSupported':
                log.error(_(u"D-Bus is not launched, please see README to see instructions on how to launch it"))
                raise BridgeInitError
            else:
                raise e
        #props = self.db_core_iface.getProperties()

    def register(self, functionName, handler, iface="core"):
        if iface == "core":
            self.db_core_iface.connect_to_signal(functionName, handler)
        elif iface == "plugin":
            self.db_plugin_iface.connect_to_signal(functionName, handler)
        else:
            log.error(_('Unknown interface'))

    def __getattribute__(self, name):
        """ usual __getattribute__ if the method exists, else try to find a plugin method """
        try:
            return object.__getattribute__(self, name)
        except AttributeError:
            # The attribute is not found, we try the plugin proxy to find the requested method

            def getPluginMethod(*args, **kwargs):
                # We first check if we have an async call. We detect this in two ways:
                #   - if we have the 'callback' and 'errback' keyword arguments
                #   - or if the last two arguments are callable

                async = False

                if kwargs:
                    if 'callback' in kwargs:
                        async = True
                        _callback = kwargs.pop('callback')
                        _errback = kwargs.pop('errback', lambda failure: log.error(unicode(failure)))
                elif len(args) >= 2 and callable(args[-1]) and callable(args[-2]):
                    async = True
                    args = list(args)
                    _errback = args.pop()
                    _callback = args.pop()

                method = getattr(self.db_plugin_iface, name)

                if async:
                    kwargs['timeout'] = const_TIMEOUT
                    kwargs['reply_handler'] = _callback
                    kwargs['error_handler'] = lambda err: _errback(dbus_to_bridge_exception(err))

                return method(*args, **kwargs)

            return getPluginMethod

    def addContact(self, entity_jid, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.addContact(entity_jid, profile_key, **kwargs)

    def asyncConnect(self, profile_key="@DEFAULT@", password='', callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return self.db_core_iface.asyncConnect(profile_key, password, timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler)

    def asyncCreateProfile(self, profile, password='', callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return self.db_core_iface.asyncCreateProfile(profile, password, timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler)

    def asyncDeleteProfile(self, profile, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return self.db_core_iface.asyncDeleteProfile(profile, timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler)

    def asyncGetParamA(self, name, category, attribute="value", security_limit=-1, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return unicode(self.db_core_iface.asyncGetParamA(name, category, attribute, security_limit, profile_key, timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler))

    def confirmationAnswer(self, id, accepted, data, profile, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.confirmationAnswer(id, accepted, data, profile, **kwargs)

    def delContact(self, entity_jid, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return self.db_core_iface.delContact(entity_jid, profile_key, timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler)

    def discoInfos(self, entity_jid, profile_key, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return self.db_core_iface.discoInfos(entity_jid, profile_key, timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler)

    def discoItems(self, entity_jid, profile_key, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return self.db_core_iface.discoItems(entity_jid, profile_key, timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler)

    def disconnect(self, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.disconnect(profile_key, **kwargs)

    def getConfig(self, section, name, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return unicode(self.db_core_iface.getConfig(section, name, **kwargs))

    def getContacts(self, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return self.db_core_iface.getContacts(profile_key, timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler)

    def getContactsFromGroup(self, group, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.getContactsFromGroup(group, profile_key, **kwargs)

    def getEntitiesData(self, jids, keys, profile, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.getEntitiesData(jids, keys, profile, **kwargs)

    def getEntityData(self, jid, keys, profile, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.getEntityData(jid, keys, profile, **kwargs)

    def getHistory(self, from_jid, to_jid, limit, between=True, search='', profile="@NONE@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return self.db_core_iface.getHistory(from_jid, to_jid, limit, between, search, profile, timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler)

    def getMainResource(self, contact_jid, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return unicode(self.db_core_iface.getMainResource(contact_jid, profile_key, **kwargs))

    def getMenuHelp(self, menu_id, language, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return unicode(self.db_core_iface.getMenuHelp(menu_id, language, **kwargs))

    def getMenus(self, language, security_limit, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.getMenus(language, security_limit, **kwargs)

    def getParamA(self, name, category, attribute="value", profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return unicode(self.db_core_iface.getParamA(name, category, attribute, profile_key, **kwargs))

    def getParams(self, security_limit=-1, app='', profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return unicode(self.db_core_iface.getParams(security_limit, app, profile_key, timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler))

    def getParamsCategories(self, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.getParamsCategories(**kwargs)

    def getParamsForCategory(self, category, security_limit=-1, app='', profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return unicode(self.db_core_iface.getParamsForCategory(category, security_limit, app, profile_key, timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler))

    def getParamsUI(self, security_limit=-1, app='', profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return unicode(self.db_core_iface.getParamsUI(security_limit, app, profile_key, timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler))

    def getPresenceStatuses(self, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.getPresenceStatuses(profile_key, **kwargs)

    def getProfileName(self, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return unicode(self.db_core_iface.getProfileName(profile_key, **kwargs))

    def getProfilesList(self, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.getProfilesList(**kwargs)

    def getProgress(self, id, profile, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.getProgress(id, profile, **kwargs)

    def getReady(self, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return self.db_core_iface.getReady(timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler)

    def getVersion(self, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return unicode(self.db_core_iface.getVersion(**kwargs))

    def getWaitingConf(self, profile_key, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.getWaitingConf(profile_key, **kwargs)

    def getWaitingSub(self, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.getWaitingSub(profile_key, **kwargs)

    def isConnected(self, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.isConnected(profile_key, **kwargs)

    def launchAction(self, callback_id, data, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return self.db_core_iface.launchAction(callback_id, data, profile_key, timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler)

    def loadParamsTemplate(self, filename, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.loadParamsTemplate(filename, **kwargs)

    def paramsRegisterApp(self, xml, security_limit=-1, app='', callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.paramsRegisterApp(xml, security_limit, app, **kwargs)

    def saveParamsTemplate(self, filename, callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.saveParamsTemplate(filename, **kwargs)

    def sendMessage(self, to_jid, message, subject='', mess_type="auto", extra={}, profile_key="@NONE@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return self.db_core_iface.sendMessage(to_jid, message, subject, mess_type, extra, profile_key, timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler)

    def setParam(self, name, value, category, security_limit=-1, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.setParam(name, value, category, security_limit, profile_key, **kwargs)

    def setPresence(self, to_jid='', show='', statuses={}, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.setPresence(to_jid, show, statuses, profile_key, **kwargs)

    def subscription(self, sub_type, entity, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        kwargs={}
        if callback is not None:
            kwargs['timeout'] = const_TIMEOUT
            kwargs['reply_handler'] = callback
            kwargs['error_handler'] = error_handler
        return self.db_core_iface.subscription(sub_type, entity, profile_key, **kwargs)

    def updateContact(self, entity_jid, name, groups, profile_key="@DEFAULT@", callback=None, errback=None):
        if callback is None:
            error_handler = None
        else:
            if errback is None:
                errback = log.error
            error_handler = lambda err:errback(dbus_to_bridge_exception(err))
        return self.db_core_iface.updateContact(entity_jid, name, groups, profile_key, timeout=const_TIMEOUT, reply_handler=callback, error_handler=error_handler)