From 69968dec867053e38de0b91d76ac41d5a5735e36 Mon Sep 17 00:00:00 2001
From: Vendula Poncova <vponcova@redhat.com>
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 <hongxu.jia@windriver.com>
---
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