Question

是否可以编写Python脚本，以便在Windows上添加或删除USB设备时调用该函数？

libusb（以及相应的python模块，例如libusb1）似乎是最受欢迎的解决方案，但它在Windows中缺少对热插拔回调注册的支持。自2015年以来，feature request已为此开放，但仍未实现。

我已经看到一些黑客以一定的时间间隔查询Windows的USB设备，对当前设备列表与先前的设备列表进行比较，并将其用作替代方法。由于我的应用程序的性质，这种黑客行为会带来巨大的安全风险，并且不是有效的解决方案。我需要对USB热插拔事件进行 actual 回调注册。

尽管不太理想，但我愿意writing something in C or C++，然后在需要时编写与该代码的python绑定。

在Windows上连接或断开USB设备时是否可以调用python函数？

Answer 1

是的，您可以在python中使用ctypes为WM_DEVICECHANGE消息注册回调。

我能够在Linux（使用libusb1 python模块）和Windows（使用ctypes python模块）中成功向USB热插拔事件添加注册回调函数。大部分相关的Windows代码可以在这里找到：

https://github.com/BusKill/buskill-app/blob/6c84587b25f7ef3b5300d8c0eda354b11051215e/src/buskill.py#L212-L275

主要基于以下链接中的代码：

import win32api, win32con, win32gui
from ctypes import *

#
# Device change events (WM_DEVICECHANGE wParam)
#
DBT_DEVICEARRIVAL = 0x8000
DBT_DEVICEQUERYREMOVE = 0x8001
DBT_DEVICEQUERYREMOVEFAILED = 0x8002
DBT_DEVICEMOVEPENDING = 0x8003
DBT_DEVICEREMOVECOMPLETE = 0x8004
DBT_DEVICETYPESSPECIFIC = 0x8005
DBT_CONFIGCHANGED = 0x0018

#
# type of device in DEV_BROADCAST_HDR
#
DBT_DEVTYP_OEM = 0x00000000
DBT_DEVTYP_DEVNODE = 0x00000001
DBT_DEVTYP_VOLUME = 0x00000002
DBT_DEVTYPE_PORT = 0x00000003
DBT_DEVTYPE_NET = 0x00000004

#
# media types in DBT_DEVTYP_VOLUME
#
DBTF_MEDIA = 0x0001
DBTF_NET = 0x0002

WORD = c_ushort
DWORD = c_ulong


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


class DEV_BROADCAST_VOLUME(Structure):
    _fields_ = [
        ("dbcv_size", DWORD),
        ("dbcv_devicetype", DWORD),
        ("dbcv_reserved", DWORD),
        ("dbcv_unitmask", DWORD),
        ("dbcv_flags", WORD)
    ]


def drive_from_mask(mask):
    n_drive = 0
    while 1:
        if (mask & (2 ** n_drive)):
            return n_drive
        else:
            n_drive += 1


class Notification:
    def __init__(self):
        message_map = {
            win32con.WM_DEVICECHANGE: self.onDeviceChange
        }

        wc = win32gui.WNDCLASS()
        hinst = wc.hInstance = win32api.GetModuleHandle(None)
        wc.lpszClassName = "DeviceChangeDemo"
        wc.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW
        wc.hCursor = win32gui.LoadCursor(0, win32con.IDC_ARROW)
        wc.hbrBackground = win32con.COLOR_WINDOW
        wc.lpfnWndProc = message_map
        classAtom = win32gui.RegisterClass(wc)
        style = win32con.WS_OVERLAPPED | win32con.WS_SYSMENU
        self.hwnd = win32gui.CreateWindow(
            classAtom,
            "Device Change Demo",
            style,
            0, 0,
            win32con.CW_USEDEFAULT, win32con.CW_USEDEFAULT,
            0, 0,
            hinst, None
        )

    def onDeviceChange(self, hwnd, msg, wparam, lparam):
        #
        # WM_DEVICECHANGE:
        #  wParam - type of change: arrival, removal etc.
        #  lParam - what's changed?
        #    if it's a volume then...
        #  lParam - what's changed more exactly
        #
        dev_broadcast_hdr = DEV_BROADCAST_HDR.from_address(lparam)

        if wparam == DBT_DEVICEARRIVAL:
            print("Something's arrived")

            if dev_broadcast_hdr.dbch_devicetype == DBT_DEVTYP_VOLUME:
                print("It's a volume!")

                dev_broadcast_volume = DEV_BROADCAST_VOLUME.from_address(lparam)
                if dev_broadcast_volume.dbcv_flags & DBTF_MEDIA:
                    print("with some media")
                    drive_letter = drive_from_mask(dev_broadcast_volume.dbcv_unitmask)
                    print("in drive", chr(ord("A") + drive_letter))

        return 1


if __name__ == '__main__':
    w = Notification()
    win32gui.PumpMessages()

在Windows上使用python进行USB热插拔回调

1 个答案: