问题描述
我的目标是建立一个Python脚本，该脚本可让我根据条形码签入和签出项目。我已经完成了脚本的主要功能，但仍遵守规范。
我希望能够强制USB设备的输出始终是我的python脚本的输入。我不希望python脚本接受键盘击键。我希望脚本拦截来自扫描仪的所有输入，以便在运行脚本时仍可以使用我的计算机。
我尝试过使用PyUSB，但我不明白如何使它在我的特定用例下工作。
我尝试将https://github.com/vpatron/barcode_scanner_python处的代码与PyUSB文档一起用作参考，但是，我没有收到正确的输入。
这是我对设备的USB规格：
7200N:
Product ID: 0x26e1
Vendor ID: 0x2dd6
Version: 1c.20
Serial Number: YS7249BC0286
Speed: Up to 12 Mb/sec
Manufacturer: SuperLead
Location ID: 0x14222000 / 10
Current Available (mA): 500
Current Required (mA): 400
Extra Operating Current (mA): 0
这是我的代码当前的样子（从上面的链接复制用于测试目的，对产品ID和供应商ID进行了更改，现在我只是想看看是否可以正确读取输入内容）
import usb.core
import usb.util
def hid2ascii(lst):
"""The USB HID device sends an 8-byte code for every character. This
routine converts the HID code to an ASCII character.
See https://www.usb.org/sites/default/files/documents/hut1_12v2.pdf
for a complete code table. Only relevant codes are used here."""
# Example input from scanner representing the string "http:":
# array('B',[0,11,0]) # h
# array('B',23,0]) # t
# array('B',0]) # nothing,ignore
# array('B',19,0]) # p
# array('B',[2,51,0]) # :
assert len(lst) == 8,'Invalid data length (needs 8 bytes)'
conv_table = {
0:['',''],4:['a','A'],5:['b','B'],6:['c','C'],7:['d','D'],8:['e','E'],9:['f','F'],10:['g','G'],11:['h','H'],12:['i','I'],13:['j','J'],14:['k','K'],15:['l','L'],16:['m','M'],17:['n','N'],18:['o','O'],19:['p','P'],20:['q','Q'],21:['r','R'],22:['s','S'],23:['t','T'],24:['u','U'],25:['v','V'],26:['w','W'],27:['x','X'],28:['y','Y'],29:['z','Z'],30:['1','!'],31:['2','@'],32:['3','#'],33:['4','$'],34:['5','%'],35:['6','^'],36:['7','&'],37:['8','*'],38:['9','('],39:['0',')'],40:['\n','\n'],41:['\x1b','\x1b'],42:['\b','\b'],43:['\t','\t'],44:[' ',' '],45:['_','_'],46:['=','+'],47:['[','{'],48:[']','}'],49:['\\','|'],50:['#','~'],51:[';',':'],52:["'",'"'],53:['`',54:[',','<'],55:['.','>'],56:['/','?'],100:['\\',103:['=','='],}
# A 2 in first byte seems to indicate to shift the key. For example
# a code for ';' but with 2 in first byte really means ':'.
if lst[0] == 2:
shift = 1
else:
shift = 0
# The character to convert is in the third byte
ch = lst[2]
if ch not in conv_table:
print ("Warning: data not in conversion table")
return ''
return conv_table[ch][shift]
# find our device
dev = usb.core.find(idVendor=0x2dd6,idProduct=0x26e1)
if dev is None:
raise ValueError('USB device not found')
# Disconnect it from kernel
needs_reattach = False
if dev.is_kernel_driver_active(0):
needs_reattach = True
dev.detach_kernel_driver(0)
print ("Detached USB device from kernel driver")
# set the active configuration. With no arguments,the first
# configuration will be the active one
dev.set_configuration()
# get an endpoint instance
cfg = dev.get_active_configuration()
intf = cfg[(0,0)]
ep = usb.util.find_descriptor(
intf,# match the first IN endpoint
custom_match = \
lambda e: \
usb.util.endpoint_direction(e.bEndpointAddress) == \
usb.util.ENDPOINT_IN)
assert ep is not None,("Endpoint for USB device not found. Something is wrong.")
# Loop through a series of 8-byte transactions and convert each to an
# ASCII character. Print output after 0.5 seconds of no data.
line = ''
while True:
try:
# Wait up to 0.5 seconds for data. 500 = 0.5 second timeout.
data = ep.read(1000,500)
ch = hid2ascii(data)
line += ch
except KeyboardInterrupt:
print ("Stopping program")
dev.reset()
if needs_reattach:
dev.attach_kernel_driver(0)
print ("Reattached USB device to kernel driver")
break
except usb.core.USBError:
# Timed out. End of the data stream. Print the scan line.
if len(line) > 0:
print (line)
line = ''
扫描仪的输入如下所示：
000045或000084
基本上只是键入字符，然后是EOL，而不是串行
上面的代码绝对不执行任何操作，只是一个while循环，但是我的输入没有输出任何内容...
解决方法
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