获取Linux中可用WiFi连接的列表

Question

我试图通过D-Bus消息，使用Qt5获取Fedora 31 Linux中SSID的列表。

我查看了许多教程，但仍然无法通过D-Bus进行通信，而且我仍然不理解接口、路径和服务之间的区别。有文档帮助(https://developer.gnome.org/NetworkManager/stable/spec.html)和我写的互联网：

QDBusInterface nm("org.freedesktop.NetworkManager", "/org/freedesktop/NetworkManager", "org.freedesktop.NetworkManager.Device.Wireless", QDBusConnection::systemBus());
if(nm.isValid()) {
QDBusMessage msg = nm.call("GetAllAccessPoints");
}

但是变量"msg"接收一个参数：

"No interface „org.freedesktop.NetworkManager.Device.Wireless” in  object at path /org/freedesktop/NetworkManager"

如何连接D-Bus？

Answer 1

您的困惑是合理的，因为这个过程并不直观。基本上，您需要做的是首先创建一个代表NetworkManager本身的QDBusInterface。通过该对象，您需要获得网络接口的列表，对其进行迭代，过滤掉WiFi接口，创建相应的QDBusInterface，指示接口扫描可用网络，然后请求可见接入点的列表。然后获得每个接入点对象的SSID属性。下面是一个简单的例子，它演示了使用普通Qt:的过程

listrongsid.pro:

QT -= gui
QT += dbus
SOURCES += list_ssid.cpp

listrongsid.cpp：

#include <QtCore/QCoreApplication>
#include <QtCore/QDebug>
#include <QtCore/QStringList>
#include <QtDBus/QtDBus>
#include <QDebug>
#include <QThread>
int main(int argc, char **argv)
{
QCoreApplication app(argc, argv);
// get the interface to nm    
QDBusInterface nm("org.freedesktop.NetworkManager", "/org/freedesktop/NetworkManager",
"org.freedesktop.NetworkManager", QDBusConnection::systemBus());
if(!nm.isValid())
{
qFatal("Failed to connect to the system bus");
}
// get all devices
QDBusMessage msg = nm.call("GetDevices");
qDebug() << "GetDevices reply: " << msg << endl;
QDBusArgument arg = msg.arguments().at(0).value<QDBusArgument>();
if(arg.currentType() != QDBusArgument::ArrayType)
{
qFatal("Something went wrong with getting the device list");
}
QList<QDBusObjectPath> pathsLst = qdbus_cast<QList<QDBusObjectPath> >(arg);
foreach(QDBusObjectPath p, pathsLst)
{
qDebug() << "DEV PATH: " << p.path();
// creating an interface used to gather this devices properties
QDBusInterface device("org.freedesktop.NetworkManager", p.path(),
"org.freedesktop.NetworkManager.Device", QDBusConnection::systemBus());
// 2 is WiFi dev, see https://people.freedesktop.org/~lkundrak/nm-docs/nm-dbus-types.html#NMDeviceType
if (device.property("DeviceType").toInt() != 2) 
{
continue;
}
// we got a wifi device, let's get an according dbus interface
QDBusInterface wifi_device("org.freedesktop.NetworkManager", p.path(),
"org.freedesktop.NetworkManager.Device.Wireless", QDBusConnection::systemBus());
// we need to call scan on the inteface prior to request the list of interfaces
QMap<QString, QVariant> argList;
QDBusMessage msg = wifi_device.call("RequestScan", argList);
QThread::sleep(2); // not the best solution, but here we just wait for the scan
// doing the actual call
msg = wifi_device.call("GetAllAccessPoints");
qDebug()<< "Answer for GetAllAccessPoints:  " << msg << endl << endl;
// dig out the paths of the Access Point objects:
QDBusArgument ap_list_arg = msg.arguments().at(0).value<QDBusArgument>();
QList<QDBusObjectPath> ap_path_list = qdbus_cast<QList<QDBusObjectPath> >(ap_list_arg);
// and iterate through the list
foreach(QDBusObjectPath p ,ap_path_list)
{
// for each Access Point we create an interface
QDBusInterface ap_interface("org.freedesktop.NetworkManager", p.path(),
"org.freedesktop.NetworkManager.AccessPoint", QDBusConnection::systemBus());
// and getting the name of the SSID
qDebug() << "SSID: " << ap_interface.property("Ssid").toString();
}
}

return 0;
}

同样使用networkmanager qt，为了进行比较：

CMakeLists.txt:

project(ssid_list LANGUAGES CXX)
set(CMAKE_INCLUDE_CURRENT_DIR ON)
set(CMAKE_AUTOUIC ON)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
find_package(Qt5 REQUIRED COMPONENTS
Core
Gui
Network
DBus
)
find_package(KF5NetworkManagerQt REQUIRED)
add_executable(ssid_list
ssid_list.cpp
)
target_link_libraries(ssid_list Qt5::Core Qt5::DBus Qt5::Network KF5::NetworkManagerQt)

ssid_list.cpp

#include <arpa/inet.h>
#include <QThread>
#include <NetworkManagerQt/Manager>
#include <NetworkManagerQt/Device>
#include <NetworkManagerQt/WirelessDevice>
#include <NetworkManagerQt/AccessPoint>
int main()
{
// getting all of the devices, and iterate through them
NetworkManager::Device::List list = NetworkManager::networkInterfaces();
Q_FOREACH (NetworkManager::Device::Ptr dev, list)
{
if(dev->type() != NM_DEVICE_TYPE_WIFI)
{
//skipping non-wifi interfaces
continue;
}
// creating a Wifi device with this object path
NetworkManager::WirelessDevice wifi_dev(dev->uni());
wifi_dev.requestScan();
QThread::sleep(2); // still not the best solution:w
//get the Object Path of all the visible access points
// and iterate through
foreach(QString ap_path, wifi_dev.accessPoints())
{
// creating an AccessPoint object with this path
NetworkManager::AccessPoint ap(ap_path);
// and finally get the SSID
qDebug() << "SSID:" << ap.ssid();
}
}
}