python - 如何解决 “control message failed, win error: A device which does not exist was specified”错误PyUSB

Question

我正在尝试将POS收据打印机连接到python，并且一直在使用python-escpos这样做。我正在运行Windows 10。

我在文件“print.py”中的代码是:

from escpos.printer import Usb

p = Usb(0x0456,0x0808)

p.text('Hello World\n')

但是当我运行它时，出现以下错误日志:

Traceback (most recent call last):
  File "C:\Users\Harry\AppData\Local\Programs\Python\Python36-32\lib\site-packages\usb\core.py", line 223, in get_interface_and_endpoint
    return self._ep_info[endpoint_address]
KeyError: 1

在处理上述异常期间，发生了另一个异常:

Traceback (most recent call last):
  File "print.py", line 5, in <module>
    p.text('Hello World\n')
  File "C:\Users\Harry\AppData\Local\Programs\Python\Python36-32\lib\site-packages\escpos\escpos.py", line 437, in text
    self._raw(txt.encode())
  File "C:\Users\Harry\AppData\Local\Programs\Python\Python36-32\lib\site-packages\escpos\printer.py", line 73, in _raw
    self.device.write(self.out_ep, msg, self.timeout)
  File "C:\Users\Harry\AppData\Local\Programs\Python\Python36-32\lib\site-packages\usb\core.py", line 940, in write
    intf, ep = self._ctx.setup_request(self, endpoint)
  File "C:\Users\Harry\AppData\Local\Programs\Python\Python36-32\lib\site-packages\usb\core.py", line 102, in wrapper
    return f(self, *args, **kwargs)
  File "C:\Users\Harry\AppData\Local\Programs\Python\Python36-32\lib\site-packages\usb\core.py", line 215, in setup_request
    intf, ep = self.get_interface_and_endpoint(device, endpoint_address)
  File "C:\Users\Harry\AppData\Local\Programs\Python\Python36-32\lib\site-packages\usb\core.py", line 102, in wrapper
    return f(self, *args, **kwargs)
  File "C:\Users\Harry\AppData\Local\Programs\Python\Python36-32\lib\site-packages\usb\core.py", line 225, in get_interface_and_endpoint
    for intf in self.get_active_configuration(device):
  File "C:\Users\Harry\AppData\Local\Programs\Python\Python36-32\lib\site-packages\usb\core.py", line 102, in wrapper
    return f(self, *args, **kwargs)
  File "C:\Users\Harry\AppData\Local\Programs\Python\Python36-32\lib\site-packages\usb\core.py", line 239, in get_active_configuration
    bConfigurationValue=self.backend.get_configuration(self.handle)
  File "C:\Users\Harry\AppData\Local\Programs\Python\Python36-32\lib\site-packages\usb\backend\libusb0.py", line 510, in get_configuration
    100)
  File "C:\Users\Harry\AppData\Local\Programs\Python\Python36-32\lib\site-packages\usb\backend\libusb0.py", line 593, in ctrl_transfer
    timeout
  File "C:\Users\Harry\AppData\Local\Programs\Python\Python36-32\lib\site-packages\usb\backend\libusb0.py", line 431, in _check
    raise USBError(errmsg, ret)
usb.core.USBError: [Errno None] b'libusb0-dll:err [control_msg] sending control message failed, win error: A device which does not exist was specified.\r\n\n'

有谁知道我需要做些什么才能使这项工作。
我已经将libusb安装到了System32和SysWOW64文件夹中，以及使用zadig为我的打印机安装了libusb-32驱动程序。

我使用的打印机是“Hoin 58mm POS打印机”。

如果有人可以向我解释为什么我有这个错误以及如何解决它，我将不胜感激!

Answer 1

首先，您可以检查此link以获取完整的线程。

As suggested by KM4YRI,

I ran into the same No backend available exception when trying to follow the tutorial on a Windows 7 machine. The following worked for me, per one of the StackOverflow replies:

1. Download the latest Windows binary: https://sourceforge.net/projects/libusb/files/libusb-1.0/libusb-1.0.21/libusb-1.0.21.7z/download

2. Unzip using 7zip into a temp dir

3. If on 64-bit Windows, copy `MS64\dll\libusb-1.0.dll` into `C:\windows\system32`.  If on 32-bit windows, copy `MS32\dll\libusb-1.0.dll` into `C:\windows\SysWOW64`.

我已经在 Windows-10 64位版本上验证了以上答案。