From 69968dec867053e38de0b91d76ac41d5a5735e36 Mon Sep 17 00:00:00 2001 From: Vendula Poncova Date: Thu, 2 Aug 2018 15:31:56 +0800 Subject: [PATCH 2/2] Support transformation between D-Bus errors and exceptions. Exceptions can be registered with decorators, raised in a remote method and recreated after return from the remote call. Upstream-Status: Cherry-pick [https://src.fedoraproject.org/cgit/rpms/python-pydbus.git/] Signed-off-by: Hongxu Jia --- pydbus/error.py | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++ pydbus/proxy_method.py | 18 ++++++++-- pydbus/registration.py | 16 ++++++--- 3 files changed, 123 insertions(+), 8 deletions(-) create mode 100644 pydbus/error.py diff --git a/pydbus/error.py b/pydbus/error.py new file mode 100644 index 0000000..aaa3510 --- /dev/null +++ b/pydbus/error.py @@ -0,0 +1,97 @@ +from gi.repository import GLib, Gio + + +def register_error(name, domain, code): + """Register and map decorated exception class to a DBus error.""" + def decorated(cls): + error_registration.register_error(cls, name, domain, code) + return cls + + return decorated + + +def map_error(error_name): + """Map decorated exception class to a DBus error.""" + def decorated(cls): + error_registration.map_error(cls, error_name) + return cls + + return decorated + + +def map_by_default(cls): + """Map decorated exception class to all unknown DBus errors.""" + error_registration.map_by_default(cls) + return cls + + +class ErrorRegistration(object): + """Class for mapping exceptions to DBus errors.""" + + _default = None + _map = dict() + _reversed_map = dict() + + def map_by_default(self, exception_cls): + """Set the exception class as a default.""" + self._default = exception_cls + + def map_error(self, exception_cls, name): + """Map the exception class to a DBus name.""" + self._map[name] = exception_cls + self._reversed_map[exception_cls] = name + + def register_error(self, exception_cls, name, domain, code): + """Map and register the exception class to a DBus name.""" + self.map_error(exception_cls, name) + return Gio.DBusError.register_error(domain, code, name) + + def is_registered_exception(self, obj): + """Is the exception registered?""" + return obj.__class__ in self._reversed_map + + def get_dbus_name(self, obj): + """Get the DBus name of the exception.""" + return self._reversed_map.get(obj.__class__) + + def get_exception_class(self, name): + """Get the exception class mapped to the DBus name.""" + return self._map.get(name, self._default) + + def transform_message(self, name, message): + """Transform the message of the exception.""" + prefix = "{}:{}: ".format("GDBus.Error", name) + + if message.startswith(prefix): + return message[len(prefix):] + + return message + + def transform_exception(self, e): + """Transform the remote error to the exception.""" + if not isinstance(e, GLib.Error): + return e + + if not Gio.DBusError.is_remote_error(e): + return e + + # Get DBus name of the error. + name = Gio.DBusError.get_remote_error(e) + # Get the exception class. + exception_cls = self.get_exception_class(name) + + # Return the original exception. + if not exception_cls: + return e + + # Return new exception. + message = self.transform_message(name, e.message) + exception = exception_cls(message) + exception.dbus_name = name + exception.dbus_domain = e.domain + exception.dbus_code = e.code + return exception + + +# Default error registration. +error_registration = ErrorRegistration() diff --git a/pydbus/proxy_method.py b/pydbus/proxy_method.py index 4ea4304..e9496f5 100644 --- a/pydbus/proxy_method.py +++ b/pydbus/proxy_method.py @@ -2,6 +2,7 @@ from gi.repository import GLib from .generic import bound_method from .identifier import filter_identifier from .timeout import timeout_to_glib +from .error import error_registration try: from inspect import Signature, Parameter @@ -87,9 +88,20 @@ class ProxyMethod(object): call_args += (self._finish_async_call, (callback, callback_args)) instance._bus.con.call(*call_args) return None + else: - ret = instance._bus.con.call_sync(*call_args) - return self._unpack_return(ret) + result = None + error = None + + try: + result = instance._bus.con.call_sync(*call_args) + except Exception as e: + error = error_registration.transform_exception(e) + + if error: + raise error + + return self._unpack_return(result) def _unpack_return(self, values): ret = values.unpack() @@ -108,7 +120,7 @@ class ProxyMethod(object): ret = source.call_finish(result) return_args = self._unpack_return(ret) except Exception as err: - error = err + error = error_registration.transform_exception(err) callback, callback_args = user_data callback(*callback_args, returned=return_args, error=error) diff --git a/pydbus/registration.py b/pydbus/registration.py index f531539..1d2cbcb 100644 --- a/pydbus/registration.py +++ b/pydbus/registration.py @@ -5,6 +5,7 @@ from . import generic from .exitable import ExitableWithAliases from functools import partial from .method_call_context import MethodCallContext +from .error import error_registration import logging try: @@ -91,11 +92,16 @@ class ObjectWrapper(ExitableWithAliases("unwrap")): logger = logging.getLogger(__name__) logger.exception("Exception while handling %s.%s()", interface_name, method_name) - #TODO Think of a better way to translate Python exception types to DBus error types. - e_type = type(e).__name__ - if not "." in e_type: - e_type = "unknown." + e_type - invocation.return_dbus_error(e_type, str(e)) + if error_registration.is_registered_exception(e): + name = error_registration.get_dbus_name(e) + invocation.return_dbus_error(name, str(e)) + else: + logger.info("name is not registered") + e_type = type(e).__name__ + if not "." in e_type: + e_type = "unknown." + e_type + + invocation.return_dbus_error(e_type, str(e)) def Get(self, interface_name, property_name): type = self.readable_properties[interface_name + "." + property_name] -- 2.7.4