使用 python-dbus 读取完整的 NetworkManager 连接信息

Question

我试图在 python 中询问 dbus，让 NetworkManager 告诉我连接是否配置为尝试自动连接到网络。

当我使用 nmcli 检查 NetworkManager 连接时，我得到如下输出

connection.id:                          my_wifi
connection.uuid:                        f36e1220-cf36-4254-b790-6d21b70ff76a
connection.stable-id:                   --
connection.type:                        802-11-wireless
connection.interface-name:              wlan0
connection.autoconnect:                 yes
connection.autoconnect-priority:        1
connection.autoconnect-retries:         -1 (default)
connection.multi-connect:               0 (default)
connection.auth-retries:                -1
connection.timestamp:                   1690711294
connection.read-only:                   no
connection.permissions:                 --
connection.zone:                        --
connection.master:                      --
connection.slave-type:                  --
connection.autoconnect-slaves:          -1 (default)
connection.secondaries:                 --
connection.gateway-ping-timeout:        0
connection.metered:                     unknown
connection.lldp:                        default
connection.mdns:                        -1 (default)
connection.llmnr:                       -1 (default)
connection.wait-device-timeout:         -1
...

我们可以看到其中显示了connection.autoconnect参数。

但是，如果我尝试使用连接对象上的 GetSettings 方法从 PyQt 程序获取相同的信息，我会得到：

connection:
   id:
      my_wifi
   interface-name:
      wlan0
   permissions:
      <Empty Array>
   timestamp:
      1689966080
   type:
      802-11-wireless
   uuid:
      f36e1220-cf36-4254-b790-6d21b70ff76a
802-11-wireless:
....

这里是查询dbus的代码源码。 （请注意，如果没有格式化代码，我得到的相同结果的可读性较差，因此这不是人为的。）

#!/usr/bin/env python3
# The code below is released under a public domain licence

from dbus import SystemBus, Interface
from dbus.types import Dictionary, String, Array, ByteArray, Byte

# Output formatting code
def display_data(structure, indent: int = 0):

   prefix = ""
   for i in range (indent):
      prefix +=  "   "

   if type(structure) == Dictionary:
      if len(structure) == 0:
         print(f"{prefix}<Empty Dict>")
      else:
         for element in structure:
            if type(structure[element] == Dictionary):
               print(f"{prefix}{element}:")
               display_data(structure[element], indent + 1)
            else:
               display_data("structure[element]")
   elif type(structure) == Array:
      if len(structure) == 0:
         print(f"{prefix}<Empty Array>")
      elif type(structure[0]) == Byte:
         print(f"{prefix}{''.join([str(c) for c in structure])}")

      else:
         for array_element in structure:
            print(f"{prefix}{array_element}")

   else: 
      if type(structure) == String and len(structure) == 0:
         print(f"{prefix}<Empty Value>")
      print(f"{prefix}{structure}")

# Dbus probe code
interface_netman = "org.freedesktop.NetworkManager"
path_netman_settings = "/org/freedesktop/NetworkManager/Settings"

interface_settings = "org.freedesktop.NetworkManager.Settings"
interface_connection = "org.freedesktop.NetworkManager.Settings.Connection"

bus = SystemBus()

settings_proxy = bus.get_object(interface_netman, path_netman_settings) 
settings = Interface(settings_proxy, interface_settings)

connection_list = settings.ListConnections()

out = {}

for connection in connection_list:
   this_connection = bus.get_object(interface_netman, connection)
   this_connection_interface = Interface(this_connection, interface_connection)        
   this_connection_settings = this_connection_interface.GetSettings()

   display_data(this_connection_settings)

我预计当我运行上面的代码时，我会得到与 nmcli 输出相同的信息，包括连接是否启用了自动连接，但提供的信息要有限得多。

所以我的问题是 nmcli 从哪里获取额外的连接信息，以及如何访问它？

Answer 1

事实证明，GetSettings() 不会为connection.autoconnect 返回值，除非将其设置为非默认值（即“no”）。