Python Dbus：如何导出接口属性

问题描述

在所有python dbus文档中，都有关于如何导出对象，接口，信号的信息，但是没有如何导出接口属性的信息。

In all python dbus documentations there are info on how to export objects, interfaces, signals, but there is nothing how to export interface property.

任何想法如何去做 ？

Any ideas how to do that ?

推荐答案

使用Python实现D-Bus属性绝对有可能！ D-Bus属性只是特定接口上的方法，即 org.freedesktop.DBus.Properties 。该接口在D-Bus规范中 ;您可以像实现任何其他D-Bus接口一样在您的类上实现它：

It's definitely possible to implement D-Bus properties in Python! D-Bus properties are just methods on a particular interface, namely org.freedesktop.DBus.Properties. The interface is defined in the D-Bus specification; you can implement it on your class just like you implement any other D-Bus interface:

# Untested, just off the top of my head

import dbus

MY_INTERFACE = 'com.example.Foo'

class Foo(dbus.service.object):
    # …

    @dbus.service.method(interface=dbus.PROPERTIES_IFACE,
                         in_signature='ss', out_signature='v')
    def Get(self, interface_name, property_name):
        return self.GetAll(interface_name)[property_name]

    @dbus.service.method(interface=dbus.PROPERTIES_IFACE,
                         in_signature='s', out_signature='a{sv}')
    def GetAll(self, interface_name):
        if interface_name == MY_INTERFACE:
            return { 'Blah': self.blah,
                     # …
                   }
        else:
            raise dbus.exceptions.DBusException(
                'com.example.UnknownInterface',
                'The Foo object does not implement the %s interface'
                    % interface_name)

    @dbus.service.method(interface=dbus.PROPERTIES_IFACE,
                         in_signature='ssv'):
    def Set(self, interface_name, property_name, new_value):
        # validate the property name and value, update internal state…
        self.PropertiesChanged(interface_name,
            { property_name: new_value }, [])

    @dbus.service.signal(interface=dbus.PROPERTIES_IFACE,
                         signature='sa{sv}as')
    def PropertiesChanged(self, interface_name, changed_properties,
                          invalidated_properties):
        pass

dbus-python应该

dbus-python ought to make it easier to implement properties, but it currently is very lightly maintained at best.

如果有人幻想潜水并帮助解决此类问题，那么他们将是最多的人。欢迎。甚至在文档中添加此样板的扩展版本也是一个开始，因为这是一个非常常见的问题。如果您有兴趣，可以将补丁发送到，或附加到错误

If someone fancied diving in and helping fix up stuff like this, they'd be most welcome. Even adding an expanded version of this boilerplate to the documentation would be a start, as this is quite a frequently asked question. If you're interested, patches could be sent to the D-Bus mailing list, or attached to bugs

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