使用NetworkManager和Python断开WiFi接入点的连接

我正在构建一个Python应用程序,该应用程序必须能够在Linux盒子上与Wifi连接和断开连接.我使用的是NetworkManager层,它是通过在守护程序(命名为Stationed)中的cnetworkmanager(NetworkManager http://vidner.net/martin/software/cnetworkmanager/ thanx到Martin Vidner的Python CLI)中找到的漂亮的networkmanager库来实现的.
该守护程序运行一个gobject.MainLoop.一旦timeout_add_seconds唤醒(通过用户在GUI中的操作触发),我必须断开当前正在运行的Wifi并连接到新的Wifi：

from dbus.mainloop.glib import DBusGMainLoop
DBusGMainLoop(set_as_default=True)

from networkmanager import NetworkManager
import networkmanager.applet.settings as settings
from networkmanager.applet import USER_SERVICE 
from networkmanager.applet.service import NetworkManagerUserSettings, NetworkManagerSettings
import time
import memcache

import gobject
loop = gobject.MainLoop()

nm = NetworkManager()

dummy_handler = lambda *args: None

cache = memcache.Client(['127.0.0.1:11211',] )


def get_device(dev_spec, hint):
    candidates = []
    devs = NetworkManager().GetDevices()
    for dev in devs:
        if dev._settings_type() == hint:
            candidates.append(dev)
    if len(candidates) == 1:
        return candidates[0]
    for dev in devs:
        if dev["Interface"] == dev_spec:
            return dev
    print "Device '%s' not found" % dev_spec
    return None

def kill_allconnections():
    connections=nm['ActiveConnections']
    for c in connections:
        print c.object_path
        nm.DeactivateConnection(c.object_path)

class Wifi(object):

    def connect(self, ssid, security="open", password=None):
        "Connects to given Wifi network"
        c=None # connection settings
        us = NetworkManagerUserSettings([])
        if security=="open":
            c = settings.WiFi(ssid)
        elif security=="wep":
            c = settings.Wep(ssid, password)
        elif security=="wpa":
            c = settings.WpaPsk(ssid, password)
        else:
            raise AttributeError("invalid security model '%s'"%security)
        svc = USER_SERVICE
        svc_conn = us.addCon(c.conmap)
        hint = svc_conn.settings["connection"]["type"]
        dev = get_device("", hint)
        appath = "/"
        nm.ActivateConnection(svc, svc_conn, dev, appath, reply_handler=dummy_handler, error_handler=dummy_handler)


def change_network_settings():
    key="station:network:change"
    change=cache.get(key)
    if change is not None:
        print "DISCONNECT"
        kill_allconnections()
        print "CHANGE SETTINGS"
        wifi=cache.get(key+':wifi')
        if wifi is not None:
            ssid=cache.get(key+':wifi:ssid')
            security=cache.get(key+':wifi:security')
            password=cache.get(key+':wifi:password')
            print "SWITCHING TO %s"%ssid
            Wifi().connect(ssid, security, password)
        cache.delete(key)
    return True    

def mainloop():
   gobject.timeout_add_seconds(1, change_network_settings)
   try:
      loop.run()
   except KeyboardInterrupt:
      loop.quit()

if __name__=="__main__":
    mainloop()

这对于第一次连接来说非常理想(请阅读：未连接盒子,运行守护程序,盒子完美连接到Wifi).问题是当我尝试连接到另一个Wifi时：kill_allconnections()静默运行,并且connect方法在nm.ActivateConnection上引发异常：

Traceback (most recent call last):
  File "stationd.py", line 40, in change_network_settings
    Wifi().connect(ssid, security, password)
  File "/home/biopredictive/station/lib/network.py", line 88, in connect
    us = NetworkManagerUserSettings([])
  File "/home/biopredictive/station/lib/networkmanager/applet/service/__init__.py", line 71, in __init__
    super(NetworkManagerUserSettings, self).__init__(conmaps, USER_SERVICE)
  File "/home/biopredictive/station/lib/networkmanager/applet/service/__init__.py", line 33, in __init__
    dbus.service.Object.__init__(self, bus, opath, bus_name)
  File "/usr/lib/pymodules/python2.6/dbus/service.py", line 480, in __init__
    self.add_to_connection(conn, object_path)
  File "/usr/lib/pymodules/python2.6/dbus/service.py", line 571, in add_to_connection
    self._fallback)
KeyError: "Can't register the object-path handler for '/org/freedesktop/NetworkManagerSettings': there is already a handler"

看来我以前的联系没有释放所有资源？
我刚接触gobject / dbus编程.你能帮忙吗？

解决方法:

我在D-Bus邮件列表上有answered.在这里引用存档：

class Wifi(...):
    def connect(...):
        ...
        us = NetworkManagerUserSettings([]) 

NetworkManagerUserSettings是服务器,而不是客户端. (这是一个设计
在NM 0.9中被消除的NM怪癖)
您只能为守护程序创建一个,而不是为每个连接创建一个
尝试.

标签：dbus,gobject,python
来源： https://codeday.me/bug/20191201/2083874.html