--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libervia/backend/bridge/bridge_constructor/constructors/pb/pb_frontend_template.py	Fri Jun 02 11:49:51 2023 +0200
@@ -0,0 +1,199 @@
+#!/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
+from logging import getLogger
+from functools import partial
+from pathlib import Path
+from twisted.spread import pb
+from twisted.internet import reactor, defer
+from twisted.internet.error import ConnectionRefusedError, ConnectError
+from libervia.backend.core import exceptions
+from libervia.backend.tools import config
+from sat_frontends.bridge.bridge_frontend import BridgeException
+
+log = getLogger(__name__)
+
+
+class SignalsHandler(pb.Referenceable):
+    def __getattr__(self, name):
+        if name.startswith("remote_"):
+            log.debug("calling an unregistered signal: {name}".format(name=name[7:]))
+            return lambda *args, **kwargs: None
+
+        else:
+            raise AttributeError(name)
+
+    def register_signal(self, name, handler, iface="core"):
+        log.debug("registering signal {name}".format(name=name))
+        method_name = "remote_" + name
+        try:
+            self.__getattribute__(method_name)
+        except AttributeError:
+            pass
+        else:
+            raise exceptions.InternalError(
+                "{name} signal handler has been registered twice".format(
+                    name=method_name
+                )
+            )
+        setattr(self, method_name, handler)
+
+
+class bridge(object):
+
+    def __init__(self):
+        self.signals_handler = SignalsHandler()
+
+    def __getattr__(self, name):
+        return partial(self.call, name)
+
+    def _generic_errback(self, err):
+        log.error(f"bridge error: {err}")
+
+    def _errback(self, failure_, ori_errback):
+        """Convert Failure to BridgeException"""
+        ori_errback(
+            BridgeException(
+                name=failure_.type.decode('utf-8'),
+                message=str(failure_.value)
+            )
+        )
+
+    def remote_callback(self, result, callback):
+        """call callback with argument or None
+
+        if result is not None not argument is used,
+        else result is used as argument
+        @param result: remote call result
+        @param callback(callable): method to call on result
+        """
+        if result is None:
+            callback()
+        else:
+            callback(result)
+
+    def call(self, name, *args, **kwargs):
+        """call a remote method
+
+        @param name(str): name of the bridge method
+        @param args(list): arguments
+            may contain callback and errback as last 2 items
+        @param kwargs(dict): keyword arguments
+            may contain callback and errback
+        """
+        callback = errback = None
+        if kwargs:
+            try:
+                callback = kwargs.pop("callback")
+            except KeyError:
+                pass
+            try:
+                errback = kwargs.pop("errback")
+            except KeyError:
+                pass
+        elif len(args) >= 2 and callable(args[-1]) and callable(args[-2]):
+            errback = args.pop()
+            callback = args.pop()
+        d = self.root.callRemote(name, *args, **kwargs)
+        if callback is not None:
+            d.addCallback(self.remote_callback, callback)
+        if errback is not None:
+            d.addErrback(errback)
+
+    def _init_bridge_eb(self, failure_):
+        log.error("Can't init bridge: {msg}".format(msg=failure_))
+        return failure_
+
+    def _set_root(self, root):
+        """set remote root object
+
+        bridge will then be initialised
+        """
+        self.root = root
+        d = root.callRemote("initBridge", self.signals_handler)
+        d.addErrback(self._init_bridge_eb)
+        return d
+
+    def get_root_object_eb(self, failure_):
+        """Call errback with appropriate bridge error"""
+        if failure_.check(ConnectionRefusedError, ConnectError):
+            raise exceptions.BridgeExceptionNoService
+        else:
+            raise failure_
+
+    def bridge_connect(self, callback, errback):
+        factory = pb.PBClientFactory()
+        conf = config.parse_main_conf()
+        get_conf = partial(config.get_conf, conf, "bridge_pb", "")
+        conn_type = get_conf("connection_type", "unix_socket")
+        if conn_type == "unix_socket":
+            local_dir = Path(config.config_get(conf, "", "local_dir")).resolve()
+            socket_path = local_dir / "bridge_pb"
+            reactor.connectUNIX(str(socket_path), factory)
+        elif conn_type == "socket":
+            host = get_conf("host", "localhost")
+            port = int(get_conf("port", 8789))
+            reactor.connectTCP(host, port, factory)
+        else:
+            raise ValueError(f"Unknown pb connection type: {conn_type!r}")
+        d = factory.getRootObject()
+        d.addCallback(self._set_root)
+        if callback is not None:
+            d.addCallback(lambda __: callback())
+        d.addErrback(self.get_root_object_eb)
+        if errback is not None:
+            d.addErrback(lambda failure_: errback(failure_.value))
+        return d
+
+    def register_signal(self, functionName, handler, iface="core"):
+        self.signals_handler.register_signal(functionName, handler, iface)
+
+
+##METHODS_PART##
+
+class AIOSignalsHandler(SignalsHandler):
+
+    def register_signal(self, name, handler, iface="core"):
+        async_handler = lambda *args, **kwargs: defer.Deferred.fromFuture(
+            asyncio.ensure_future(handler(*args, **kwargs)))
+        return super().register_signal(name, async_handler, iface)
+
+
+class AIOBridge(bridge):
+
+    def __init__(self):
+        self.signals_handler = AIOSignalsHandler()
+
+    def _errback(self, failure_):
+        """Convert Failure to BridgeException"""
+        raise BridgeException(
+            name=failure_.type.decode('utf-8'),
+            message=str(failure_.value)
+            )
+
+    def call(self, name, *args, **kwargs):
+        d = self.root.callRemote(name, *args, *kwargs)
+        d.addErrback(self._errback)
+        return d.asFuture(asyncio.get_event_loop())
+
+    async def bridge_connect(self):
+        d = super().bridge_connect(callback=None, errback=None)
+        return await d.asFuture(asyncio.get_event_loop())
+
+##ASYNC_METHODS_PART##