Pyscard无法列出读卡器

Question

我有一个ACR38读卡器，使用的是Python2.7。我在网上找了很多方法来用Python和读卡器进行通信，最后找到了下面的代码，链接在这里

import sys
sys.path.append('D:\PythonX\Lib\site-packages')
from smartcard.scard import *
import smartcard.util

SELECT = [0x00, 0xA4, 0x04, 0x00, 0x0A, 0xA0, 0x00, 0x00, 0x00, 0x62,
    0x03, 0x01, 0x0C, 0x06, 0x01]
COMMAND = [0x00, 0x00, 0x00, 0x00]

try:
    hresult, hcontext = SCardEstablishContext(SCARD_SCOPE_USER)
    if hresult != SCARD_S_SUCCESS:
        raise Exception('Failed to establish context : ' +
            SCardGetErrorMessage(hresult))
    print 'Context established!'

    try:
        hresult, readers = SCardListReaders(hcontext, [])
        if hresult != SCARD_S_SUCCESS:
            raise Exception('Failed to list readers: ' +
                SCardGetErrorMessage(hresult))
        print 'PCSC Readers:', readers

        if len(readers) < 1:
            raise Exception('No smart card readers')

        reader = readers[0]
        print "Using reader:", reader

        try:
            hresult, hcard, dwActiveProtocol = SCardConnect(hcontext, reader,
                SCARD_SHARE_SHARED, SCARD_PROTOCOL_T0 | SCARD_PROTOCOL_T1)
            if hresult != SCARD_S_SUCCESS:
                raise Exception('Unable to connect: ' +
                    SCardGetErrorMessage(hresult))
            print 'Connected with active protocol', dwActiveProtocol

            try:
                hresult, response = SCardTransmit(hcard, dwActiveProtocol,
                    SELECT)
                if hresult != SCARD_S_SUCCESS:
                    raise Exception('Failed to transmit: ' +
                        SCardGetErrorMessage(hresult))
                print 'Select: ' + smartcard.util.toHexString(response,
                    smartcard.util.HEX)
                hresult, response = SCardTransmit(hcard, dwActiveProtocol,
                    COMMAND)
                if hresult != SCARD_S_SUCCESS:
                    raise Exception('Failed to transmit: ' +
                        SCardGetErrorMessage(hresult))
                print 'Command: ' + smartcard.util.toHexString(response,
                    smartcard.util.HEX)
            finally:
                hresult = SCardDisconnect(hcard, SCARD_UNPOWER_CARD)
                if hresult != SCARD_S_SUCCESS:
                    raise Exception('Failed to disconnect: ' +
                        SCardGetErrorMessage(hresult))
                print 'Disconnected'

        except Exception, message:
            print "Exception:", message

    finally:
        hresult = SCardReleaseContext(hcontext)
        if hresult != SCARD_S_SUCCESS:
            raise Exception('Failed to release context: ' +
                    SCardGetErrorMessage(hresult))
        print 'Released context.'

except Exception, message:
    print "Exception:", message

import sys
if 'win32' == sys.platform:
    print 'press Enter to continue'
    sys.stdin.read(1)

但是当我运行这段代码时，出现了下面的错误：

>>> ================================ RESTART ================================
>>> 
Context established!
Released context.
Exception: Failed to list readers: Cannot find a smart card reader. 
press Enter to continue

Traceback (most recent call last):
  File "C:/Users/ghasemi.IT/Desktop/123", line 76, in <module>
    sys.stdin.read(1)
AttributeError: read
>>> ================================ RESTART ================================

问：为什么我在设备管理器的libusb-win32设备下能看到我的读卡器，却无法列出读卡器？我需要卸载Libusb吗？

Answer 1

你在代码中看不到读卡器的原因是因为你混用了两种不同的方法：

1. 你的代码尝试使用pyscard，这是一个用于PC/SC接口的Python封装库。
2. 你让libusb来管理ACR38这个USB设备。

libusb是一个可以直接访问USB设备的库，所以如果你让libusb的USB驱动来管理读卡器，你就需要使用libusb的接口库来从你的程序中访问读卡器。

如果你想使用pyscard（PC/SC），那么你也需要让PC/SC来管理读卡器。在这种情况下，你需要为这个读卡器安装一个CCID驱动，而不是libusb驱动。ACS提供了一个PC/SC驱动包，里面包含了这个读卡器所需的驱动。