PythonスタディノートでPyUSBを使用する場合の例外処理（Pyinstallerのパッケージ化後にバックエンドで使用可能な問題は発生しません）

Exception Handling When Using Pyusb Python Study Notes

小さなソフトウェアを作成する場合、PyUSB + zadig-2.4.exeまたはlibusb-win32-bin-1.2.6.0.zipを使用した後、libusbxを検出しないシステムがないため、Pyinstallerのパッケージ後にバックエンドが利用できないという問題が発生します。現在の環境変数の下。 dllライブラリファイル

現在の妥協方法は、sb.core.find（find_all = True）を呼び出すときに、渡されるバックエンドのカスタムインターフェイスメソッドは次のとおりです。

import os,sys import usb.core import usb.util import usb.control import logging import usb.backend.libusb1 as libusb1 import usb.backend.libusb0 as libusb0 import usb.backend.openusb as openusb from usb.libloader import * _LOGGER = logging.getLogger(__name__) os.environ['PYUSB_DEBUG'] = 'debug' def _load_locate_library_ex(candidates, cygwin_lib, name, win_cls=None, cygwin_cls=None, others_cls=None, find_library=None): '''Locates and loads a library. Returns: the loaded library arguments: * candidates -- candidates list for locate_library() * cygwin_lib -- name of the cygwin library * name -- lib identifier (for logging). Defaults to None. * win_cls -- class that is used to instantiate the library on win32 platforms. Defaults to None (-> ctypes.CDLL). * cygwin_cls -- library class for cygwin platforms. Defaults to None (-> ctypes.CDLL). * others_cls -- library class for all other platforms. Defaults to None (-> ctypes.CDLL). * find_library -- see locate_library(). Defaults to None. raises: * NoLibraryCandidatesException * LibraryNotFoundException * LibraryNotLoadedException * LibraryMissingSymbolsException ''' if sys.platform == 'cygwin': if cygwin_lib: loaded_lib = load_library(cygwin_lib, name, cygwin_cls) else: raise NoLibraryCandidatesException(name) elif candidates: lib = locate_library(candidates, find_library) if lib: if sys.platform == 'win32': loaded_lib = load_library(lib, name, win_cls) else: loaded_lib = load_library(lib, name, others_cls) _LOGGER.info('{}'.format(loaded_lib)) else: _LOGGER.info('%r could not be found', (name or candidates)) raise LibraryNotFoundException(name) else: raise NoLibraryCandidatesException(name) if loaded_lib is None: raise LibraryNotLoadedException(name) else: return loaded_lib def _load_library_ex(find_library=None): return _load_locate_library_ex( ('usb-0.1', 'usb', 'libusb0'), 'cygusb0.dll', 'Libusb 0', find_library=find_library ) def _get_backend_ex(): try: if libusb0._lib is None: _LOGGER.info('_get_backend_ex(): using backend '%s'' % libusb0.__name__) libusb0._lib = _load_library_ex()#find_library libusb0._setup_prototypes(libusb0._lib) libusb0._lib.usb_init() return libusb0._LibUSB() except usb.libloader.LibraryException: # exception already logged (if any) _LOGGER.error('Error loading libusb 0.1 backend') return None except Exception: _LOGGER.error('Error loading libusb 0.1 backend') return None def my_get_backend_ex(): for m in (libusb1, openusb, libusb0): backend = m.get_backend() if backend is not None: _LOGGER.info('my_get_backend_ex(): using backend '%s'' % m.__name__) break elif m == libusb0: backend = _get_backend_ex() if backend is not None: break else: raise ('No backend available') return backend def testFind(): backend = my_get_backend_ex() print (list(usb.core.find(find_all=True, backend=backend))) if __name__ == '__main__': testFind()

出力結果：

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使用するUSB​​デバイスは次のとおりです。