← Volver

Cómo detectar la inserción o remoción de un dispositivo USB

El siguiente código forma parte de los ejemplos del paquete pywin32, que permite acceder a la API de Windows desde Python.

# Demo RegisterDeviceNotification etc.  Creates a hidden window to receive
# notifications. See serviceEvents.py for an example of a service doing
# that.
import sys, time
import win32gui, win32con, win32api, win32file
import win32gui_struct, winnt

# These device GUIDs are from Ioevent.h in the Windows SDK. Ideally they
# could be collected somewhere for pywin32...
GUID_DEVINTERFACE_USB_DEVICE = "{A5DCBF10-6530-11D2-901F-00C04FB951ED}"

# WM_DEVICECHANGE message handler.
def OnDeviceChange(hwnd, msg, wp, lp):
# Unpack the 'lp' into the appropriate DEV_BROADCAST_* structure,
# using the self-identifying data inside the DEV_BROADCAST_HDR.
info = win32gui_struct.UnpackDEV_BROADCAST(lp)
print("Device change notification:", wp, str(info))
if wp==win32con.DBT_DEVICEQUERYREMOVE and info.devicetype==win32con.DBT_DEVTYP_HANDLE:
# Our handle is stored away in the structure - just close it
print("Device being removed - closing handle")
win32file.CloseHandle(info.handle)
# and cancel our notifications - if it gets plugged back in we get
# the same notification and try and close the same handle...
win32gui.UnregisterDeviceNotification(info.hdevnotify)
return True


def TestDeviceNotifications(dir_names):
wc = win32gui.WNDCLASS()
wc.lpszClassName = 'test_devicenotify'
wc.style = win32con.CS_GLOBALCLASS|win32con.CS_VREDRAW | win32con.CS_HREDRAW
wc.hbrBackground = win32con.COLOR_WINDOW+1
wc.lpfnWndProc={win32con.WM_DEVICECHANGE:OnDeviceChange}
class_atom=win32gui.RegisterClass(wc)
hwnd = win32gui.CreateWindow(wc.lpszClassName,
'Testing some devices',
# no need for it to be visible.
win32con.WS_CAPTION,
100,100,900,900, 0, 0, 0, None)

hdevs = []
# Watch for all USB device notifications
filter = win32gui_struct.PackDEV_BROADCAST_DEVICEINTERFACE(
GUID_DEVINTERFACE_USB_DEVICE)
hdev = win32gui.RegisterDeviceNotification(hwnd, filter,
win32con.DEVICE_NOTIFY_WINDOW_HANDLE)
hdevs.append(hdev)
# and create handles for all specified directories
for d in dir_names:
hdir = win32file.CreateFile(d,
winnt.FILE_LIST_DIRECTORY,
winnt.FILE_SHARE_READ | winnt.FILE_SHARE_WRITE | winnt.FILE_SHARE_DELETE,
None, # security attributes
win32con.OPEN_EXISTING,
win32con.FILE_FLAG_BACKUP_SEMANTICS | # required privileges: SE_BACKUP_NAME and SE_RESTORE_NAME.
win32con.FILE_FLAG_OVERLAPPED,
None)

filter = win32gui_struct.PackDEV_BROADCAST_HANDLE(hdir)
hdev = win32gui.RegisterDeviceNotification(hwnd, filter,
win32con.DEVICE_NOTIFY_WINDOW_HANDLE)
hdevs.append(hdev)

# now start a message pump and wait for messages to be delivered.
print("Watching", len(hdevs), "handles - press Ctrl+C to terminate, or")
print("add and remove some USB devices...")
if not dir_names:
print("(Note you can also pass paths to watch on the command-line - eg,")
print("pass the root of an inserted USB stick to see events specific to")
print("that volume)")
while 1:
win32gui.PumpWaitingMessages()
time.sleep(0.01)
win32gui.DestroyWindow(hwnd)
win32gui.UnregisterClass(wc.lpszClassName, None)

if __name__=='__main__':
# optionally pass device/directory names to watch for notifications.
# Eg, plug in a USB device - assume it connects as E: - then execute:
# % win32gui_devicenotify.py E:
# Then remove and insert the device.
TestDeviceNotifications(sys.argv[1:])

Para poder ejecutar este código se debe instalar pywin32 vía python -m pip install pywin32.

¿Alguna duda sobre este código? ¡Preguntanos en el foro!