Python evdev和條形碼掃描器

Question

我有一個下面的代碼，我用它來捕捉來自條形碼掃描器的輸入。問題是，我要保存在數據庫全掃描碼，但對新行代碼打印每一個字符：

#!/usr/bin/env python 

from evdev import InputDevice, ecodes, list_devices 
from select import select 

keys = "X^1234567890XXXXqwertzuiopXXXXasdfghjklXXXXXyxcvbnmXXXXXXXXXXXXXXXXXXXXXXX" 
dev = InputDevice("/dev/input/event10") 

barcode = "" 
while True: 
    r,w,x = select([dev], [], []) 

    for event in dev.read(): 
     if event.type == 1 and event.value == 1: 
      barcode += (keys[event.code]) 

    print barcode 

# sudo ./bar-code-test.py                   
#0 
#00 
#00 
#000 
#001 
#1001 
#0017 
#70017 
#00170 
#000170 
#001708 
#8001708 
#0017085 
#50017085 
#00170853 
#300170853 
#001708531 
#1001708531 
#0017085316 
#60017085316 
#00170853160 
#000170853160 
#001708531601 
#1001708531601 
#0017085316013 
#30017085316013 
#00170853160131 
#100170853160131 
#00170853160131X 
#00170853160131X 

我與蟒蛇新手，所以任何幫助將不勝感激。

Answer 1

找到了解決方案。每次掃描的代碼後，條碼掃描儀發送42的掃描碼（回車鍵），所以我們需要檢查掃描代碼：

#!/usr/bin/env python 

from evdev import InputDevice, ecodes, list_devices, categorize 
import signal, sys 

scancodes = { 
    # Scancode: ASCIICode 
    0: None, 1: u'ESC', 2: u'1', 3: u'2', 4: u'3', 5: u'4', 6: u'5', 7: u'6', 8: u'7', 9: u'8', 
    10: u'9', 11: u'0', 12: u'-', 13: u'=', 14: u'BKSP', 15: u'TAB', 16: u'Q', 17: u'W', 18: u'E', 19: u'R', 
    20: u'T', 21: u'Y', 22: u'U', 23: u'I', 24: u'O', 25: u'P', 26: u'[', 27: u']', 28: u'CRLF', 29: u'LCTRL', 
    30: u'A', 31: u'S', 32: u'D', 33: u'F', 34: u'G', 35: u'H', 36: u'J', 37: u'K', 38: u'L', 39: u';', 
    40: u'"', 41: u'`', 42: u'LSHFT', 43: u'\\', 44: u'Z', 45: u'X', 46: u'C', 47: u'V', 48: u'B', 49: u'N', 
    50: u'M', 51: u',', 52: u'.', 53: u'/', 54: u'RSHFT', 56: u'LALT', 100: u'RALT' 
} 
barCodeDeviceString = "Metrologic Metrologic Scanner" 

devices = map(InputDevice, list_devices()) 
for device in devices: 
    if device.name == barCodeDeviceString: 
     dev = InputDevice(device.fn) 

def signal_handler(signal, frame): 
    print 'Stopping' 
    dev.ungrab() 
    sys.exit(0) 

signal.signal(signal.SIGINT, signal_handler) 

dev.grab() 

barcode = "" 
for event in dev.read_loop(): 
    if event.type == ecodes.EV_KEY: 
     data = categorize(event) 
     if data.keystate == 1 and data.scancode != 42: # Catch only keydown, and not Enter 
      if data.scancode == 28: 
       print barcode 
       barcode = "" 
      else: 
       barcode += keys[data.scancode] 

Answer 2

如果你讀的字符串的長度，以及關於什麼的，直到達到您的期望值或長度，您退出循環並打印出條形碼讀取。

我修改了這樣的代碼，它只是打印一行文字：

#!/usr/bin/env python 

from evdev import InputDevice, ecodes, list_devices 
from select import select 

keys = "X^1234567890XXXXqwertzuiopXXXXasdfghjklXXXXXyxcvbnmXXXXXXXXXXXXXXXXXXXXXXX" 
dev = InputDevice("/dev/input/event1") 

barcode = "" 
while True: 
    r,w,x = select([dev], [], []) 

    for event in dev.read(): 
     if event.type == 1 and event.value == 1: 
      barcode += (keys[event.code]) 
    if (len (barcode)) > 13: 
    break; 



print barcode 

我試圖在Arduino的雲，與OpenWrt的，和它的工作只是罰款：

root@Arduino:/mnt/sda1# python pybar.py 
7501483187071X 

問候，