Mercurial > libervia-backend
diff src/bridge/bridge_constructor/constructors/dbus/dbus_frontend_template.py @ 2085:da4097de5a95
bridge (constructor): refactoring:
- constructors are now in separate modules
- constructors are discovered dynamically
- factorised generation code from D-Bus in base Constructor.
- A generic generation method is now available in base Constructor, using python formatting.
- removed bridge/bridge.py in core as it was useless, may come back in the future if needed
author | Goffi <goffi@goffi.org> |
---|---|
date | Sun, 02 Oct 2016 22:44:33 +0200 |
parents | src/bridge/bridge_constructor/dbus_frontend_template.py@2daf7b4c6756 |
children | 4633cfcbcccb |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/bridge/bridge_constructor/constructors/dbus/dbus_frontend_template.py Sun Oct 02 22:44:33 2016 +0200 @@ -0,0 +1,137 @@ +#!/usr/bin/env python2 +#-*- coding: utf-8 -*- + +# SAT communication bridge +# Copyright (C) 2009-2016 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 in ('org.freedesktop.DBus.Error.ServiceUnknown', + 'org.freedesktop.DBus.Error.Spawn.ExecFailed'): + 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 + args = list(args) + + if kwargs: + if 'callback' in kwargs: + async = True + _callback = kwargs.pop('callback') + _errback = kwargs.pop('errback', lambda failure: log.error(unicode(failure))) + try: + args.append(kwargs.pop('profile')) + except KeyError: + try: + args.append(kwargs.pop('profile_key')) + except KeyError: + pass + # at this point, kwargs should be empty + if kwargs: + log.warnings(u"unexpected keyword arguments, they will be ignored: {}".format(kwargs)) + elif len(args) >= 2 and callable(args[-1]) and callable(args[-2]): + async = True + _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 + +##METHODS_PART##