| From 773858e1afd21cdf3ceef2cd35509f0b4882bf16 Mon Sep 17 00:00:00 2001 |
| From: Vendula Poncova <vponcova@redhat.com> |
| Date: Tue, 1 Aug 2017 16:54:24 +0200 |
| Subject: [PATCH 3/3] 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. |
| |
| Adapted from Fedora [https://src.fedoraproject.org/cgit/rpms/python-pydbus.git/] |
| |
| Upstream-Status: Inactive-Upstream (Last release 12/18/2016; Last commit 05/6/2018) |
| |
| Signed-off-by: Derek Straka <derek@asterius.io> |
| --- |
| doc/tutorial.rst | 47 ++++++++++++++++++ |
| pydbus/error.py | 97 ++++++++++++++++++++++++++++++++++++ |
| pydbus/proxy_method.py | 18 +++++-- |
| pydbus/registration.py | 16 ++++-- |
| tests/error.py | 67 +++++++++++++++++++++++++ |
| tests/publish_error.py | 132 +++++++++++++++++++++++++++++++++++++++++++++++++ |
| tests/run.sh | 2 + |
| 7 files changed, 371 insertions(+), 8 deletions(-) |
| create mode 100644 pydbus/error.py |
| create mode 100644 tests/error.py |
| create mode 100644 tests/publish_error.py |
| |
| diff --git a/doc/tutorial.rst b/doc/tutorial.rst |
| index b8479cf..7fe55e1 100644 |
| --- a/doc/tutorial.rst |
| +++ b/doc/tutorial.rst |
| @@ -341,6 +341,53 @@ See ``help(bus.request_name)`` and ``help(bus.register_object)`` for details. |
| |
| .. -------------------------------------------------------------------- |
| |
| +Error handling |
| +============== |
| + |
| +You can map D-Bus errors to your exception classes for better error handling. |
| +To handle D-Bus errors, use the ``@map_error`` decorator:: |
| + |
| + from pydbus.error import map_error |
| + |
| + @map_error("org.freedesktop.DBus.Error.InvalidArgs") |
| + class InvalidArgsException(Exception): |
| + pass |
| + |
| + try: |
| + ... |
| + catch InvalidArgsException as e: |
| + print(e) |
| + |
| +To register new D-Bus errors, use the ``@register_error`` decorator:: |
| + |
| + from pydbus.error import register_error |
| + |
| + @map_error("net.lew21.pydbus.TutorialExample.MyError", MY_DOMAIN, MY_EXCEPTION_CODE) |
| + class MyException(Exception): |
| + pass |
| + |
| +Then you can raise ``MyException`` from the D-Bus method of the remote object:: |
| + |
| + def Method(): |
| + raise MyException("Message") |
| + |
| +And catch the same exception on the client side:: |
| + |
| + try: |
| + proxy.Method() |
| + catch MyException as e: |
| + print(e) |
| + |
| +To handle all unknown D-Bus errors, use the ``@map_by_default`` decorator to specify the default exception:: |
| + |
| + from pydbus.error import map_by_default |
| + |
| + @map_by_default |
| + class DefaultException(Exception): |
| + pass |
| + |
| +.. -------------------------------------------------------------------- |
| + |
| Data types |
| ========== |
| |
| 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 442fe07..a73f9eb 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] |
| diff --git a/tests/error.py b/tests/error.py |
| new file mode 100644 |
| index 0000000..3ec507d |
| --- /dev/null |
| +++ b/tests/error.py |
| @@ -0,0 +1,67 @@ |
| +from pydbus.error import ErrorRegistration |
| + |
| + |
| +class ExceptionA(Exception): |
| + pass |
| + |
| + |
| +class ExceptionB(Exception): |
| + pass |
| + |
| + |
| +class ExceptionC(Exception): |
| + pass |
| + |
| + |
| +class ExceptionD(Exception): |
| + pass |
| + |
| + |
| +class ExceptionE(Exception): |
| + pass |
| + |
| + |
| +def test_error_mapping(): |
| + r = ErrorRegistration() |
| + r.map_error(ExceptionA, "net.lew21.pydbus.tests.ErrorA") |
| + r.map_error(ExceptionB, "net.lew21.pydbus.tests.ErrorB") |
| + r.map_error(ExceptionC, "net.lew21.pydbus.tests.ErrorC") |
| + |
| + assert r.is_registered_exception(ExceptionA("Test")) |
| + assert r.is_registered_exception(ExceptionB("Test")) |
| + assert r.is_registered_exception(ExceptionC("Test")) |
| + assert not r.is_registered_exception(ExceptionD("Test")) |
| + assert not r.is_registered_exception(ExceptionE("Test")) |
| + |
| + assert r.get_dbus_name(ExceptionA("Test")) == "net.lew21.pydbus.tests.ErrorA" |
| + assert r.get_dbus_name(ExceptionB("Test")) == "net.lew21.pydbus.tests.ErrorB" |
| + assert r.get_dbus_name(ExceptionC("Test")) == "net.lew21.pydbus.tests.ErrorC" |
| + |
| + assert r.get_exception_class("net.lew21.pydbus.tests.ErrorA") == ExceptionA |
| + assert r.get_exception_class("net.lew21.pydbus.tests.ErrorB") == ExceptionB |
| + assert r.get_exception_class("net.lew21.pydbus.tests.ErrorC") == ExceptionC |
| + assert r.get_exception_class("net.lew21.pydbus.tests.ErrorD") is None |
| + assert r.get_exception_class("net.lew21.pydbus.tests.ErrorE") is None |
| + |
| + r.map_by_default(ExceptionD) |
| + assert not r.is_registered_exception(ExceptionD("Test")) |
| + assert r.get_exception_class("net.lew21.pydbus.tests.ErrorD") == ExceptionD |
| + assert r.get_exception_class("net.lew21.pydbus.tests.ErrorE") == ExceptionD |
| + |
| + |
| +def test_transform_message(): |
| + r = ErrorRegistration() |
| + n1 = "net.lew21.pydbus.tests.ErrorA" |
| + m1 = "GDBus.Error:net.lew21.pydbus.tests.ErrorA: Message1" |
| + |
| + n2 = "net.lew21.pydbus.tests.ErrorB" |
| + m2 = "GDBus.Error:net.lew21.pydbus.tests.ErrorB: Message2" |
| + |
| + assert r.transform_message(n1, m1) == "Message1" |
| + assert r.transform_message(n2, m2) == "Message2" |
| + assert r.transform_message(n1, m2) == m2 |
| + assert r.transform_message(n2, m1) == m1 |
| + |
| + |
| +test_error_mapping() |
| +test_transform_message() |
| diff --git a/tests/publish_error.py b/tests/publish_error.py |
| new file mode 100644 |
| index 0000000..aa8a18a |
| --- /dev/null |
| +++ b/tests/publish_error.py |
| @@ -0,0 +1,132 @@ |
| +import sys |
| +from threading import Thread |
| +from gi.repository import GLib, Gio |
| +from pydbus import SessionBus |
| +from pydbus.error import register_error, map_error, map_by_default, error_registration |
| + |
| +import logging |
| +logger = logging.getLogger('pydbus.registration') |
| +logger.disabled = True |
| + |
| +loop = GLib.MainLoop() |
| +DOMAIN = Gio.DBusError.quark() # TODO: Register new domain. |
| + |
| + |
| +@register_error("net.lew21.pydbus.tests.ErrorA", DOMAIN, 1000) |
| +class ExceptionA(Exception): |
| + pass |
| + |
| + |
| +@register_error("net.lew21.pydbus.tests.ErrorB", DOMAIN, 2000) |
| +class ExceptionB(Exception): |
| + pass |
| + |
| + |
| +@map_error("org.freedesktop.DBus.Error.InvalidArgs") |
| +class ExceptionC(Exception): |
| + pass |
| + |
| + |
| +@map_by_default |
| +class ExceptionD(Exception): |
| + pass |
| + |
| + |
| +class ExceptionE(Exception): |
| + pass |
| + |
| + |
| +class TestObject(object): |
| + ''' |
| +<node> |
| + <interface name='net.lew21.pydbus.tests.TestInterface'> |
| + <method name='RaiseA'> |
| + <arg type='s' name='msg' direction='in'/> |
| + </method> |
| + <method name='RaiseB'> |
| + <arg type='s' name='msg' direction='in'/> |
| + </method> |
| + <method name='RaiseD'> |
| + <arg type='s' name='msg' direction='in'/> |
| + </method> |
| + <method name='RaiseE'> |
| + <arg type='s' name='msg' direction='in'/> |
| + </method> |
| + </interface> |
| +</node> |
| + ''' |
| + |
| + def RaiseA(self, msg): |
| + raise ExceptionA(msg) |
| + |
| + def RaiseB(self, msg): |
| + raise ExceptionB(msg) |
| + |
| + def RaiseD(self, msg): |
| + raise ExceptionD(msg) |
| + |
| + def RaiseE(self, msg): |
| + raise ExceptionE(msg) |
| + |
| +bus = SessionBus() |
| + |
| +with bus.publish("net.lew21.pydbus.tests.Test", TestObject()): |
| + remote = bus.get("net.lew21.pydbus.tests.Test") |
| + |
| + def t_func(): |
| + # Test new registered errors. |
| + try: |
| + remote.RaiseA("Test A") |
| + except ExceptionA as e: |
| + assert str(e) == "Test A" |
| + |
| + try: |
| + remote.RaiseB("Test B") |
| + except ExceptionB as e: |
| + assert str(e) == "Test B" |
| + |
| + # Test mapped errors. |
| + try: |
| + remote.Get("net.lew21.pydbus.tests.TestInterface", "Foo") |
| + except ExceptionC as e: |
| + assert str(e) == "No such property 'Foo'" |
| + |
| + # Test default errors. |
| + try: |
| + remote.RaiseD("Test D") |
| + except ExceptionD as e: |
| + assert str(e) == "Test D" |
| + |
| + try: |
| + remote.RaiseE("Test E") |
| + except ExceptionD as e: |
| + assert str(e) == "Test E" |
| + |
| + # Test with no default errors. |
| + error_registration.map_by_default(None) |
| + |
| + try: |
| + remote.RaiseD("Test D") |
| + except Exception as e: |
| + assert not isinstance(e, ExceptionD) |
| + |
| + try: |
| + remote.RaiseE("Test E") |
| + except Exception as e: |
| + assert not isinstance(e, ExceptionD) |
| + assert not isinstance(e, ExceptionE) |
| + |
| + loop.quit() |
| + |
| + t = Thread(None, t_func) |
| + t.daemon = True |
| + |
| + def handle_timeout(): |
| + print("ERROR: Timeout.") |
| + sys.exit(1) |
| + |
| + GLib.timeout_add_seconds(4, handle_timeout) |
| + |
| + t.start() |
| + loop.run() |
| + t.join() |
| diff --git a/tests/run.sh b/tests/run.sh |
| index 271c58a..a08baf8 100755 |
| --- a/tests/run.sh |
| +++ b/tests/run.sh |
| @@ -10,10 +10,11 @@ PYTHON=${1:-python} |
| |
| "$PYTHON" $TESTS_DIR/context.py |
| "$PYTHON" $TESTS_DIR/identifier.py |
| +"$PYTHON" $TESTS_DIR/error.py |
| if [ "$2" != "dontpublish" ] |
| then |
| "$PYTHON" $TESTS_DIR/publish.py |
| "$PYTHON" $TESTS_DIR/publish_properties.py |
| "$PYTHON" $TESTS_DIR/publish_multiface.py |
| "$PYTHON" $TESTS_DIR/publish_async.py |
| fi |
| -- |
| 2.13.5 |