--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libervia/backend/bridge/bridge_constructor/constructors/dbus/dbus_frontend_template.py	Fri Jun 02 11:49:51 2023 +0200
@@ -0,0 +1,223 @@
+#!/usr/bin/env python3
+
+# SàT communication bridge
+# Copyright (C) 2009-2021 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/>.
+
+import asyncio
+import dbus
+import ast
+from libervia.backend.core.i18n import _
+from libervia.backend.tools import config
+from libervia.backend.core.log import getLogger
+from libervia.backend.core.exceptions import BridgeExceptionNoService, BridgeInitError
+from dbus.mainloop.glib import DBusGMainLoop
+from .bridge_frontend import BridgeException
+
+
+DBusGMainLoop(set_as_default=True)
+log = getLogger(__name__)
+
+
+# Interface prefix
+const_INT_PREFIX = config.config_get(
+    config.parse_main_conf(),
+    "",
+    "bridge_dbus_int_prefix",
+    "org.libervia.Libervia")
+const_ERROR_PREFIX = const_INT_PREFIX + ".error"
+const_OBJ_PATH = '/org/libervia/Libervia/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 bridge:
+
+    def bridge_connect(self, callback, errback):
+        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 as e:
+            if e._dbus_error_name in ('org.freedesktop.DBus.Error.ServiceUnknown',
+                                      'org.freedesktop.DBus.Error.Spawn.ExecFailed'):
+                errback(BridgeExceptionNoService())
+            elif e._dbus_error_name == 'org.freedesktop.DBus.Error.NotSupported':
+                log.error(_("D-Bus is not launched, please see README to see instructions on how to launch it"))
+                errback(BridgeInitError)
+            else:
+                errback(e)
+        else:
+            callback()
+        #props = self.db_core_iface.getProperties()
+
+    def register_signal(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 get_plugin_method(*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(str(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.warning("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))
+
+                try:
+                    return method(*args, **kwargs)
+                except ValueError as e:
+                    if e.args[0].startswith("Unable to guess signature"):
+                        # XXX: if frontend is started too soon after backend, the
+                        #   inspection misses methods (notably plugin dynamically added
+                        #   methods). The following hack works around that by redoing the
+                        #   cache of introspected methods signatures.
+                        log.debug("using hack to work around inspection issue")
+                        proxy = self.db_plugin_iface.proxy_object
+                        IN_PROGRESS = proxy.INTROSPECT_STATE_INTROSPECT_IN_PROGRESS
+                        proxy._introspect_state = IN_PROGRESS
+                        proxy._Introspect()
+                        return self.db_plugin_iface.get_dbus_method(name)(*args, **kwargs)
+                    raise e
+
+            return get_plugin_method
+
+##METHODS_PART##
+
+class AIOBridge(bridge):
+
+    def register_signal(self, functionName, handler, iface="core"):
+        loop = asyncio.get_running_loop()
+        async_handler = lambda *args: asyncio.run_coroutine_threadsafe(handler(*args), loop)
+        return super().register_signal(functionName, async_handler, iface)
+
+    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 get_plugin_method(*args, **kwargs):
+                loop = asyncio.get_running_loop()
+                fut = loop.create_future()
+                method = getattr(self.db_plugin_iface, name)
+                reply_handler = lambda ret=None: loop.call_soon_threadsafe(
+                    fut.set_result, ret)
+                error_handler = lambda err: loop.call_soon_threadsafe(
+                    fut.set_exception, dbus_to_bridge_exception(err))
+                try:
+                    method(
+                        *args,
+                        **kwargs,
+                        timeout=const_TIMEOUT,
+                        reply_handler=reply_handler,
+                        error_handler=error_handler
+                    )
+                except ValueError as e:
+                    if e.args[0].startswith("Unable to guess signature"):
+                        # same hack as for bridge.__getattribute__
+                        log.warning("using hack to work around inspection issue")
+                        proxy = self.db_plugin_iface.proxy_object
+                        IN_PROGRESS = proxy.INTROSPECT_STATE_INTROSPECT_IN_PROGRESS
+                        proxy._introspect_state = IN_PROGRESS
+                        proxy._Introspect()
+                        self.db_plugin_iface.get_dbus_method(name)(
+                            *args,
+                            **kwargs,
+                            timeout=const_TIMEOUT,
+                            reply_handler=reply_handler,
+                            error_handler=error_handler
+                        )
+
+                    else:
+                        raise e
+                return fut
+
+            return get_plugin_method
+
+    def bridge_connect(self):
+        loop = asyncio.get_running_loop()
+        fut = loop.create_future()
+        super().bridge_connect(
+            callback=lambda: loop.call_soon_threadsafe(fut.set_result, None),
+            errback=lambda e: loop.call_soon_threadsafe(fut.set_exception, e)
+        )
+        return fut
+
+##ASYNC_METHODS_PART##