dbus_helper.py

#!/usr/bin/env python

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#            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE              #
#                    Version 2, December 2004                         #
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# Copyright (C) 2010 Thomas Bertani <sylar@anche.no>                  #
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#  0. You just DO WHAT THE FUCK YOU WANT TO.                          #
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#     DO WHAT YOU WANT CAUSE A PIRATE IS FREE, YOU ARE A PIRATE!      #
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from dbus import SystemBus, Interface
from xml.etree.ElementTree import fromstring
from new import instancemethod

class Helper:
    '''
    This helper lets you simply call dbus methods as if they are provided by this class.
    The usage is Helper(path), so you have just to call the constructor with the complete path (or a part of it if it's unique) of the dbus interface whose methods you are interested in.
    
    Example: Helper("org.neophysis.nwm") or just Helper("nwm")
    '''
    __utils__ = {'bus': None, 'obj': None}
    def __init__(self, path, obj="/"):
        def addMethod(name, interface_name, single_interface, args=()):
            def f(x, *args):
                try:
                    return x.__utils__['obj'].get_dbus_method(name, interface_name)(*args)
                except TypeError: raise Exception("Wrong arguments passed..")
            f.func_name = "%s_%s" % (interface_name.split(".")[-1], name) if not single_interface else name
            f.func_doc = "Usage: %s(%s)" % (f.func_name or "f", ', '.join(arg if arg else chr(ord('a')+n) for n, arg in enumerate(args)))
            setattr(self, f.func_name, instancemethod(f, self, self.__class__))
        self.__utils__['bus'] = SystemBus()
        r = []
        for i in self.__utils__['bus'].list_names():
            r.append(i) if (i.find(path) > -1) else None
        if not len(r): raise Exception("Cannot find any matching interface as '%s'" % path)
        elif len(r) == 1: path = r[0]
        else: raise Exception("The path specified is ambiguos: %s maching interfaces found" % len(r))
        self.__utils__['obj'] = self.__utils__['bus'].get_object(path, obj)
        try: xml = fromstring(Interface(self.__utils__['obj'], "org.freedesktop.DBus.Introspectable").Introspect())
        except: raise Exception("Introspection error")
        if len(xml.findall("interface")) == 1: single_interface = True
        else: single_interface = False
        for interface in xml.findall("interface"):
            interface_name = interface.get("name")
            for children in interface._children:
                args = []
                if children.tag != "method": continue
                method_name = children.get("name")
                for c in children._children:
                    if (c.tag == "arg") and (c.get("direction") == "in"): args.append(c.get("name"))
                addMethod(method_name, interface_name, single_interface, args)