Current File : //usr/lib/python3/dist-packages/jeepney/wrappers.py
from typing import Union
from warnings import warn
from .low_level import *
__all__ = [
'DBusAddress',
'new_method_call',
'new_method_return',
'new_error',
'new_signal',
'MessageGenerator',
'Properties',
'Introspectable',
'DBusErrorResponse',
]
class DBusAddress:
"""This identifies the object and interface a message is for.
e.g. messages to display desktop notifications would have this address::
DBusAddress('/org/freedesktop/Notifications',
bus_name='org.freedesktop.Notifications',
interface='org.freedesktop.Notifications')
"""
def __init__(self, object_path, bus_name=None, interface=None):
self.object_path = object_path
self.bus_name = bus_name
self.interface = interface
def __repr__(self):
return '{}({!r}, bus_name={!r}, interface={!r})'.format(type(self).__name__,
self.object_path, self.bus_name, self.interface)
def with_interface(self, interface):
return type(self)(self.object_path, self.bus_name, interface)
class DBusObject(DBusAddress):
def __init__(self, object_path, bus_name=None, interface=None):
super().__init__(object_path, bus_name, interface)
warn('Deprecated alias, use DBusAddress instead', stacklevel=2)
def new_header(msg_type):
return Header(Endianness.little, msg_type, flags=0, protocol_version=1,
body_length=-1, serial=-1, fields={})
def new_method_call(remote_obj, method, signature=None, body=()):
"""Construct a new method call message
This is a relatively low-level method. In many cases, this will be called
from a :class:`MessageGenerator` subclass which provides a more convenient
API.
:param DBusAddress remote_obj: The object to call a method on
:param str method: The name of the method to call
:param str signature: The DBus signature of the body data
:param tuple body: Body data (i.e. method parameters)
"""
header = new_header(MessageType.method_call)
header.fields[HeaderFields.path] = remote_obj.object_path
if remote_obj.bus_name is None:
raise ValueError("remote_obj.bus_name cannot be None for method calls")
header.fields[HeaderFields.destination] = remote_obj.bus_name
if remote_obj.interface is not None:
header.fields[HeaderFields.interface] = remote_obj.interface
header.fields[HeaderFields.member] = method
if signature is not None:
header.fields[HeaderFields.signature] = signature
return Message(header, body)
def new_method_return(parent_msg, signature=None, body=()):
"""Construct a new response message
:param Message parent_msg: The method call this is a reply to
:param str signature: The DBus signature of the body data
:param tuple body: Body data
"""
header = new_header(MessageType.method_return)
header.fields[HeaderFields.reply_serial] = parent_msg.header.serial
sender = parent_msg.header.fields.get(HeaderFields.sender, None)
if sender is not None:
header.fields[HeaderFields.destination] = sender
if signature is not None:
header.fields[HeaderFields.signature] = signature
return Message(header, body)
def new_error(parent_msg, error_name, signature=None, body=()):
"""Construct a new error response message
:param Message parent_msg: The method call this is a reply to
:param str error_name: The name of the error
:param str signature: The DBus signature of the body data
:param tuple body: Body data
"""
header = new_header(MessageType.error)
header.fields[HeaderFields.reply_serial] = parent_msg.header.serial
header.fields[HeaderFields.error_name] = error_name
sender = parent_msg.header.fields.get(HeaderFields.sender, None)
if sender is not None:
header.fields[HeaderFields.destination] = sender
if signature is not None:
header.fields[HeaderFields.signature] = signature
return Message(header, body)
def new_signal(emitter, signal, signature=None, body=()):
"""Construct a new signal message
:param DBusAddress emitter: The object sending the signal
:param str signal: The name of the signal
:param str signature: The DBus signature of the body data
:param tuple body: Body data
"""
header = new_header(MessageType.signal)
header.fields[HeaderFields.path] = emitter.object_path
if emitter.interface is None:
raise ValueError("emitter.interface cannot be None for signals")
header.fields[HeaderFields.interface] = emitter.interface
header.fields[HeaderFields.member] = signal
if signature is not None:
header.fields[HeaderFields.signature] = signature
return Message(header, body)
class MessageGenerator:
"""Subclass this to define the methods available on a DBus interface.
jeepney.bindgen can automatically create subclasses using introspection.
"""
def __init__(self, object_path, bus_name):
self.object_path = object_path
self.bus_name = bus_name
def __repr__(self):
return "{}({!r}, bus_name={!r})".format(type(self).__name__,
self.object_path, self.bus_name)
class ProxyBase:
"""A proxy is an IO-aware wrapper around a MessageGenerator
Calling methods on a proxy object will send a message and wait for the
reply. This is a base class for proxy implementations in jeepney.io.
"""
def __init__(self, msggen):
self._msggen = msggen
def __getattr__(self, item):
if item.startswith('__'):
raise AttributeError(item)
make_msg = getattr(self._msggen, item, None)
if callable(make_msg):
return self._method_call(make_msg)
raise AttributeError(item)
def _method_call(self, make_msg):
raise NotImplementedError("Needs to be implemented in subclass")
class Properties:
"""Build messages for accessing object properties
If a D-Bus object has multiple interfaces, each interface has its own
set of properties.
This uses the standard DBus interface ``org.freedesktop.DBus.Properties``
"""
def __init__(self, obj: Union[DBusAddress, MessageGenerator]):
self.obj = obj
self.props_if = DBusAddress(obj.object_path, bus_name=obj.bus_name,
interface='org.freedesktop.DBus.Properties')
def get(self, name):
"""Get the value of the property *name*"""
return new_method_call(self.props_if, 'Get', 'ss',
(self.obj.interface, name))
def get_all(self):
"""Get all property values for this interface"""
return new_method_call(self.props_if, 'GetAll', 's',
(self.obj.interface,))
def set(self, name, signature, value):
"""Set the property *name* to *value* (with appropriate signature)"""
return new_method_call(self.props_if, 'Set', 'ssv',
(self.obj.interface, name, (signature, value)))
class Introspectable(MessageGenerator):
interface = 'org.freedesktop.DBus.Introspectable'
def Introspect(self):
"""Request D-Bus introspection XML for a remote object"""
return new_method_call(self, 'Introspect')
class DBusErrorResponse(Exception):
"""Raised by proxy method calls when the reply is an error message"""
def __init__(self, msg):
self.name = msg.header.fields.get(HeaderFields.error_name)
self.data = msg.body
def __str__(self):
return '[{}] {}'.format(self.name, self.data)
def unwrap_msg(msg: Message):
"""Get the body of a message, raising DBusErrorResponse for error messages
This is to be used with replies to method_call messages, which may be
method_return or error.
"""
if msg.header.message_type == MessageType.error:
raise DBusErrorResponse(msg)
return msg.body
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