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Следующий код показывает имя нового вставленного USB-накопителя в консоли (в качестве замены PyQt5 GUI) в Linux.

К сожалению, pyudev.device._errors.DeviceNotFoundAtPathError появляется в консоли, как только вы отсоединяете USB-накопитель, не извлекая его должным образом.

Что нужно изменить, чтобы исправить эту ошибку?

main.py:

 from functools import partial
import os
import sys

import pyudev

from PyQt5.QtWidgets import QApplication
from PyQt5.QtCore import QSocketNotifier, QObject, pyqtSignal


class MainWindow():

    def __init__(self, parent=None):
        super().__init__()
        # GUI code
        pass

    def print_name(self, name):
        print(name)


class LinuxDeviceMonitor(QObject):
    devices_changed = pyqtSignal(list)

    def __init__(self):
        super().__init__()
        self._context = pyudev.Context()

        self._monitor = pyudev.Monitor.from_netlink(self._context)
        self._monitor.start()

        self._devices = set()

        self._process_devices(self._context.list_devices(), action="add")

    def fileno(self):
        return self._monitor.fileno()

    @property
    def device_names(self):
        return [pyudev.Devices.from_path(self._context, device).get("DEVNAME") for device in self._devices]

    def process_incoming(self):
        read_device = partial(pyudev._util.eintr_retry_call, self._monitor.poll, timeout=0)
        self._process_devices(iter(read_device, None))
        self.devices_changed.emit(self.device_names)

    def _process_devices(self, devices, action=None):
        for device in devices:
            action = device.action if action is None else action

            if action in ("add", "change") and self._is_usb_mass_storage_device(device):
                self._devices.add(device.sys_path)
            elif action == "remove" and device.sys_path in self._devices:
                self._devices.remove(device.sys_path)

    @classmethod
    def _read_device_flag(self, device, name):
        path = os.path.join(device.sys_path, name)
        try:
            with open(path) as data:
                return bool(int(data.read()))
        except (IOError, ValueError):
            return False

    def _is_usb_mass_storage_device(self, device):
        is_removable = self._read_device_flag(device, "removable")
        has_size = self._read_device_flag(device, "size")
        has_usb = device.get("ID_BUS") == "usb"
        has_no_disc = device.get("ID_CDROM") is None
        return is_removable and has_size and has_usb and has_no_disc


def main():
    app = QApplication(sys.argv)

    main_window = MainWindow()

    linux_device_monitor = LinuxDeviceMonitor()

    notifier = QSocketNotifier(linux_device_monitor.fileno(), QSocketNotifier.Read)
    notifier.activated.connect(linux_device_monitor.process_incoming)

    linux_device_monitor.devices_changed.connect(main_window.print_name)

    sys.exit(app.exec_())


if __name__ == '__main__':
    main()
  

В моем первом ответе нет ничего плохого, но вы можете перезаписать функцию своей собственной. Ниже приведен пример этого для вашей проблемы. Основными изменениями являются:

Добавлено:

 from pyudev._util import ensure_byte_string
  

и перезаписал from_sys_path функцию:

         pyudev.Devices.from_sys_path = self.from_sys_path

    def from_sys_path(self, context, sys_path):
        device = context._libudev.udev_device_new_from_syspath(
            context, ensure_byte_string(sys_path))
        if not device:
            return None
        return pyudev.Device(context, device)
  

Изменено:

     @property
    def device_names(self):
        return [pyudev.Devices.from_path(self._context, device).get("DEVNAME") for device in self._devices]
  

Для:

     def device_names(self):
        devices = []
        for device in self._devices:
            dev = pyudev.Devices.from_path(self._context, device)
            if dev is not None:
                devices.append(dev.get("DEVNAME"))
        return devices
  

и

         self.devices_changed.emit(self.device_names)
  

Для

         self.devices_changed.emit(self.device_names())
  

Весь код выглядит следующим образом:

 from functools import partial
import os
import sys

import pyudev

from PyQt5.QtWidgets import QApplication
from PyQt5.QtCore import QSocketNotifier, QObject, pyqtSignal
from pyudev._util import ensure_byte_string


class MainWindow():

    def __init__(self, parent=None):
        super().__init__()
        # GUI code
        pass

    def print_name(self, name):
        print(name)


class LinuxDeviceMonitor(QObject):
    devices_changed = pyqtSignal(list)

    def __init__(self):
        super().__init__()
        self._context = pyudev.Context()

        self._monitor = pyudev.Monitor.from_netlink(self._context)
        self._monitor.start()

        self._devices = set()

        self._process_devices(self._context.list_devices(), action="add")
        pyudev.Devices.from_sys_path = self.from_sys_path

    def from_sys_path(self, context, sys_path):
        device = context._libudev.udev_device_new_from_syspath(
            context, ensure_byte_string(sys_path))
        if not device:
            return None
        return pyudev.Device(context, device)

    def fileno(self):
        return self._monitor.fileno()

    def device_names(self):
        devices = []
        for device in self._devices:
            dev = pyudev.Devices.from_path(self._context, device)
            if dev is not None:
                devices.append(dev.get("DEVNAME"))
        return devices

    def process_incoming(self):
        read_device = partial(pyudev._util.eintr_retry_call, self._monitor.poll, timeout=0)
        self._process_devices(iter(read_device, None))
        self.devices_changed.emit(self.device_names())

    def _process_devices(self, devices, action=None):
        for device in devices:
            action = device.action if action is None else action

            if action in ("add", "change") and self._is_usb_mass_storage_device(device):
                self._devices.add(device.sys_path)
            elif action == "remove" and device.sys_path in self._devices:
                self._devices.remove(device.sys_path)

    @classmethod
    def _read_device_flag(self, device, name):
        path = os.path.join(device.sys_path, name)
        try:
            with open(path) as data:
                return bool(int(data.read()))
        except (IOError, ValueError):
            return False

    def _is_usb_mass_storage_device(self, device):
        is_removable = self._read_device_flag(device, "removable")
        has_size = self._read_device_flag(device, "size")
        has_usb = device.get("ID_BUS") == "usb"
        has_no_disc = device.get("ID_CDROM") is None
        return is_removable and has_size and has_usb and has_no_disc


def main():
    app = QApplication(sys.argv)

    main_window = MainWindow()

    linux_device_monitor = LinuxDeviceMonitor()

    notifier = QSocketNotifier(linux_device_monitor.fileno(), QSocketNotifier.Read)
    notifier.activated.connect(linux_device_monitor.process_incoming)

    linux_device_monitor.devices_changed.connect(main_window.print_name)

    sys.exit(app.exec_())


if __name__ == '__main__':
    main()
  

Ваша среда IDE может жаловаться на то, что вы обращаетесь к защищенному элементу модуля (pyudev._util), но она все равно будет работать.

Вы могли бы просто перехватить исключение:

изменение

     @property
    def device_names(self):
        return [pyudev.Devices.from_path(self._context, device).get("DEVNAME") for device in self._devices]
  

Для

     def device_names(self):
        devices = []
        for device in self._devices:
            try:
                dev_name = pyudev.Devices.from_path(self._context, device).get("DEVNAME")
                devices.append(dev_name)
            except pyudev.DeviceNotFoundAtPathError:
                pass
        return devices
  

и

         self.devices_changed.emit(self.device_names)
  

Для

         self.devices_changed.emit(self.device_names())
  

Весь код:

 from functools import partial
import os
import sys

import pyudev

from PyQt5.QtWidgets import QApplication
from PyQt5.QtCore import QSocketNotifier, QObject, pyqtSignal


class MainWindow():

    def __init__(self, parent=None):
        super().__init__()
        # GUI code
        pass

    def print_name(self, name):
        print(name)


class LinuxDeviceMonitor(QObject):
    devices_changed = pyqtSignal(list)

    def __init__(self):
        super().__init__()
        self._context = pyudev.Context()

        self._monitor = pyudev.Monitor.from_netlink(self._context)
        self._monitor.start()

        self._devices = set()

        self._process_devices(self._context.list_devices(), action="add")

    def fileno(self):
        return self._monitor.fileno()

    def device_names(self):
        devices = []
        for device in self._devices:
            try:
                dev_name = pyudev.Devices.from_path(self._context, device).get("DEVNAME")
                devices.append(dev_name)
            except pyudev.DeviceNotFoundAtPathError:
                pass
        return devices

    def process_incoming(self):
        read_device = partial(pyudev._util.eintr_retry_call, self._monitor.poll, timeout=0)
        self._process_devices(iter(read_device, None))
        self.devices_changed.emit(self.device_names())

    def _process_devices(self, devices, action=None):
        for device in devices:
            action = device.action if action is None else action

            if action in ("add", "change") and self._is_usb_mass_storage_device(device):
                self._devices.add(device.sys_path)
            elif action == "remove" and device.sys_path in self._devices:
                self._devices.remove(device.sys_path)

    @classmethod
    def _read_device_flag(self, device, name):
        path = os.path.join(device.sys_path, name)
        try:
            with open(path) as data:
                return bool(int(data.read()))
        except (IOError, ValueError):
            return False

    def _is_usb_mass_storage_device(self, device):
        is_removable = self._read_device_flag(device, "removable")
        has_size = self._read_device_flag(device, "size")
        has_usb = device.get("ID_BUS") == "usb"
        has_no_disc = device.get("ID_CDROM") is None
        return is_removable and has_size and has_usb and has_no_disc


def main():
    app = QApplication(sys.argv)

    main_window = MainWindow()

    linux_device_monitor = LinuxDeviceMonitor()

    notifier = QSocketNotifier(linux_device_monitor.fileno(), QSocketNotifier.Read)
    notifier.activated.connect(linux_device_monitor.process_incoming)

    linux_device_monitor.devices_changed.connect(main_window.print_name)

    sys.exit(app.exec_())


if __name__ == '__main__':
    main()
  

Выводит данные при вставке и извлечении USB-накопителя:

 []
[]
[]
['/dev/sdc']
['/dev/sdc']
['/dev/sdc']
[]
[]
[]