python - 在 Windows 10 上检测 USB 输入设备的插入/移除

Question

我已经有一些可用的 Python 代码来检测某些 USB 设备类型的插入(来自 here)。

import wmi

raw_wql = "SELECT * FROM __InstanceCreationEvent WITHIN 2 WHERE TargetInstance ISA \'Win32_USBHub\'"
c = wmi.WMI()
watcher = c.watch_for(raw_wql=raw_wql)
while 1:
    usb = watcher()
    print(usb)

不幸的是，这个脚本没有检测到所有类型的 USB 设备的插入。这意味着检测到 USB 闪存驱动器的插入，但未检测到 USB 输入设备。根本没有检测到 USB 设备的移除。

有没有办法相应地扩展现有脚本？

编辑:更好的 WQL 查询和 Python 代码

我根据在 MSDN 中获得的信息改进了 WQL 查询和 Python 代码。 .

以下脚本旨在在插入或拔出 USB 键盘时输出消息。

问题:插入 USB 键盘时不会出现消息，但拔下 USB 键盘时会出现两条消息(“键盘已连接”和“键盘已断开”)。这段代码有什么问题？

import wmi

device_connected_wql = "SELECT * FROM __InstanceCreationEvent WITHIN 2 WHERE TargetInstance ISA \'Win32_Keyboard\'"
device_disconnected_wql = "SELECT * FROM __InstanceDeletionEvent WITHIN 2 WHERE TargetInstance ISA \'Win32_Keyboard\'"

c = wmi.WMI()
connected_watcher = c.watch_for(raw_wql=device_connected_wql)
disconnected_watcher = c.watch_for(raw_wql=device_disconnected_wql)

while 1:
    connected = connected_watcher()
    disconnected = disconnected_watcher()
    if connected:
        print("Keyboard connected")
    if disconnected:
        print("Keyboard disconnected")

Answer 1

有多种方法可以检测设备更改发生的情况

Detecting USB Insertion / Removal Events in Windows using C++

一种建议的方法是使用 WM_DEVICECHANGE 消息。 https://stackoverflow.com/a/4078996/2830850

一个这样的例子可以在下面找到

#Modified from: http://wiki.wxpython.org/HookingTheWndProc
##########################################################################
##
##  This is a modification of the original WndProcHookMixin by Kevin Moore,
##  modified to use ctypes only instead of pywin32, so it can be used
##  with no additional dependencies in Python 2.5
##
##########################################################################


import sys
import ctypes
#import GUID
from ctypes import c_long, c_int, wintypes

import wx


GWL_WNDPROC = -4
WM_DESTROY  = 2
DBT_DEVTYP_DEVICEINTERFACE = 0x00000005  # device interface class
DBT_DEVICEREMOVECOMPLETE = 0x8004  # device is gone
DBT_DEVICEARRIVAL = 0x8000  # system detected a new device
WM_DEVICECHANGE = 0x0219

class GUID(ctypes.Structure):
    _pack_ = 1
    _fields_ = [("Data1", ctypes.c_ulong),
                ("Data2", ctypes.c_ushort),
                ("Data3", ctypes.c_ushort),
                ("Data4", ctypes.c_ubyte * 8)]

## It's probably not neccesary to make this distinction, but it never hurts to be safe
if 'unicode' in wx.PlatformInfo:
    SetWindowLong = ctypes.windll.user32.SetWindowLongW
    CallWindowProc = ctypes.windll.user32.CallWindowProcW
else:
    SetWindowLong = ctypes.windll.user32.SetWindowLongA
    CallWindowProc = ctypes.windll.user32.CallWindowProcA

## Create a type that will be used to cast a python callable to a c callback function
## first arg is return type, the rest are the arguments
#WndProcType = ctypes.WINFUNCTYPE(c_int, wintypes.HWND, wintypes.UINT, wintypes.WPARAM, wintypes.LPARAM)
WndProcType = ctypes.WINFUNCTYPE(ctypes.c_long, ctypes.c_int, ctypes.c_uint, ctypes.c_int, ctypes.c_int)

if 'unicode' in wx.PlatformInfo:
    RegisterDeviceNotification = ctypes.windll.user32.RegisterDeviceNotificationW
else:
    RegisterDeviceNotification = ctypes.windll.user32.RegisterDeviceNotificationA
RegisterDeviceNotification.restype = wintypes.HANDLE
RegisterDeviceNotification.argtypes = [wintypes.HANDLE, wintypes.c_void_p, wintypes.DWORD]

UnregisterDeviceNotification = ctypes.windll.user32.UnregisterDeviceNotification
UnregisterDeviceNotification.restype = wintypes.BOOL
UnregisterDeviceNotification.argtypes = [wintypes.HANDLE]

class DEV_BROADCAST_DEVICEINTERFACE(ctypes.Structure):
    _fields_ = [("dbcc_size", ctypes.c_ulong),
                ("dbcc_devicetype", ctypes.c_ulong),
                ("dbcc_reserved", ctypes.c_ulong),
                ("dbcc_classguid", GUID),
                ("dbcc_name", ctypes.c_wchar * 256)]

class DEV_BROADCAST_HDR(ctypes.Structure):
    _fields_ = [("dbch_size", wintypes.DWORD),
              ("dbch_devicetype", wintypes.DWORD),
              ("dbch_reserved", wintypes.DWORD)]

GUID_DEVCLASS_PORTS = GUID(0x4D36E978, 0xE325, 0x11CE,
        (ctypes.c_ubyte*8)(0xBF, 0xC1, 0x08, 0x00, 0x2B, 0xE1, 0x03, 0x18))
GUID_DEVINTERFACE_USB_DEVICE = GUID(0xA5DCBF10L, 0x6530,0x11D2,
        (ctypes.c_ubyte*8)(0x90, 0x1F, 0x00,0xC0, 0x4F, 0xB9, 0x51, 0xED))

class WndProcHookMixin:
    """
    This class can be mixed in with any wxWindows window class in order to hook it's WndProc function.
    You supply a set of message handler functions with the function addMsgHandler. When the window receives that
    message, the specified handler function is invoked. If the handler explicitly returns False then the standard
    WindowProc will not be invoked with the message. You can really screw things up this way, so be careful.
    This is not the correct way to deal with standard windows messages in wxPython (i.e. button click, paint, etc)
    use the standard wxWindows method of binding events for that. This is really for capturing custom windows messages
    or windows messages that are outside of the wxWindows world.
    """
    def __init__(self):
        self.__msgDict = {}
        ## We need to maintain a reference to the WndProcType wrapper
        ## because ctypes doesn't
        self.__localWndProcWrapped = None
        self.rtnHandles = []

    def hookWndProc(self):
        self.__localWndProcWrapped = WndProcType(self.localWndProc)
        self.__oldWndProc = SetWindowLong(self.GetHandle(), GWL_WNDPROC, self.__localWndProcWrapped)

    def unhookWndProc(self):
        SetWindowLong(self.GetHandle(), GWL_WNDPROC, self.__oldWndProc)
        ## Allow the ctypes wrapper to be garbage collected
        self.__localWndProcWrapped = None

    def addMsgHandler(self,messageNumber,handler):
        self.__msgDict[messageNumber] = handler

    def localWndProc(self, hWnd, msg, wParam, lParam):
        # call the handler if one exists
        # performance note: "in" is the fastest way to check for a key
        # when the key is unlikely to be found
        # (which is the case here, since most messages will not have handlers).
        # This is called via a ctypes shim for every single windows message
        # so dispatch speed is important
        if msg in self.__msgDict:
            # if the handler returns false, we terminate the message here
            # Note that we don't pass the hwnd or the message along
            # Handlers should be really, really careful about returning false here
            if self.__msgDict[msg](wParam,lParam) == False:
                return

        # Restore the old WndProc on Destroy.
        if msg == WM_DESTROY: self.unhookWndProc()

        return CallWindowProc(self.__oldWndProc, hWnd, msg, wParam, lParam)

    def registerDeviceNotification(self, guid, devicetype=DBT_DEVTYP_DEVICEINTERFACE):
        devIF = DEV_BROADCAST_DEVICEINTERFACE()
        devIF.dbcc_size = ctypes.sizeof(DEV_BROADCAST_DEVICEINTERFACE)
        devIF.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE

        if guid:
            devIF.dbcc_classguid = GUID.GUID(guid)
        return RegisterDeviceNotification(self.GetHandle(), ctypes.byref(devIF), 0)

    def unregisterDeviceNotification(self, handle):
        if UnregisterDeviceNotification(handle) == 0:
            raise Exception("Unable to unregister device notification messages")


# a simple example
if __name__ == "__main__":

    class MyFrame(wx.Frame,WndProcHookMixin):
        def __init__(self,parent):
            WndProcHookMixin.__init__(self)
            wx.Frame.__init__(self,parent,-1,"Insert and Remove USE Device and Watch STDOUT",size=(640,480))

            self.Bind(wx.EVT_CLOSE, self.onClose)

            #Change the following guid to the GUID of the device you want notifications for
            #self.devNotifyHandle = self.registerDeviceNotification(guid="{3c5e1462-5695-4e18-876b-f3f3d08aaf18}")
            dbh = DEV_BROADCAST_DEVICEINTERFACE()
            dbh.dbcc_size = ctypes.sizeof(DEV_BROADCAST_DEVICEINTERFACE)
            dbh.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE
            dbh.dbcc_classguid = GUID_DEVINTERFACE_USB_DEVICE
            self.devNotifyHandle = RegisterDeviceNotification(self.GetHandle(), ctypes.byref(dbh), 0)
            self.addMsgHandler(WM_DEVICECHANGE, self.onDeviceChange)
            self.hookWndProc()

        def onDeviceChange(self,wParam,lParam):
            print "WM_DEVICECHANGE [WPARAM:%i][LPARAM:%i]"%(wParam,lParam)

            if wParam == DBT_DEVICEARRIVAL:
                print "Device Arrival"
            elif wParam == DBT_DEVICEREMOVECOMPLETE:
                print "Device Remvoed"

            if lParam:
                dbh = DEV_BROADCAST_HDR.from_address(lParam)
                if dbh.dbch_devicetype == DBT_DEVTYP_DEVICEINTERFACE:
                    dbd = DEV_BROADCAST_DEVICEINTERFACE.from_address(lParam)
                    #Verify that the USB VID and PID match our assigned VID and PID
                    if 'Vid_10c4&Pid_8382' in dbd.dbcc_name:
                        print "Was Our USB Device"

            return True

        def onClose(self, event):
            self.unregisterDeviceNotification(self.devNotifyHandle)
            event.Skip()

    app = wx.App(False)
    frame = MyFrame(None)
    frame.Show()
    app.MainLoop()

以上摘自 https://github.com/weiwei22844/UsefullPython/blob/fa8603b92cb0b3f6ce00c876f24138211f47e906/HookUsbMsg.py

现在回到你的代码

import wmi

device_connected_wql = "SELECT * FROM __InstanceCreationEvent WITHIN 2 WHERE TargetInstance ISA \'Win32_Keyboard\'"
device_disconnected_wql = "SELECT * FROM __InstanceDeletionEvent WITHIN 2 WHERE TargetInstance ISA \'Win32_Keyboard\'"

c = wmi.WMI()
connected_watcher = c.watch_for(raw_wql=device_connected_wql)
disconnected_watcher = c.watch_for(raw_wql=device_disconnected_wql)

while 1:
    connected = connected_watcher()
    disconnected = disconnected_watcher()
    if connected:
        print("Keyboard connected")
    if disconnected:
        print("Keyboard disconnected")

您的联系方式是 connected_watcher和 disconnected_watcher在系列中，两者都阻塞调用。所以当你第一次调用它时 connected变为真，然后 disconnected_watcher被调用阻塞直到设备断开连接。这就是为什么当您断开连接时，您会同时看到两条消息。

修复它的方法是确保您超时这些查询

while 1:
    try:
        connected = connected_watcher(timeout_ms=10)
    except wmi.x_wmi_timed_out:
      pass
    else:
        if connected:
            print("Keyboard connected")

    try:
        disconnected = disconnected_watcher(timeout_ms=10)
    except wmi.x_wmi_timed_out:
      pass
    else:
        if disconnected:
            print("Keyboard disconnected")

另一种方法是使用线程。但是为了让你的代码线程兼容，你需要像下面这样

class VolumeRemovalWatcher:
    def __init__(self, callback=None):
        self.stop_wanted=False
        self.callback=callback
    def stop(self):
        self.stop_wanted = True
    def watch_for_events(self):
        if not threading.current_thread() is threading.main_thread():
            pythoncom.CoInitialize()

        try:
            w = WMI()
            watcher = w.Win32_VolumeChangeEvent.watch_for(EventType=3)
            while not self.stop_wanted:
                try:
                    event = watcher(timeout_ms=1000)
                except x_wmi_timed_out:
                    pass
                else:
                    print(event.DriveName)
                    if self.callback is not None:
                        self.callback(event.DriveName)
        except Exception as e:
            print(e)
            return None
        finally:
            if not threading.current_thread() is threading.main_thread():
                pythoncom.CoUninitialize()

以上代码归功于 https://github.com/utytlanyjoe/pyWmiHandler/blob/89b934301990a4a955ec13db21caaf81d9a94f63/wmi_wrapper.py