addons/hw_scanner/controllers/main.py

   1 # -*- coding: utf-8 -*-
   2 import logging
   3 import os
   4 import time
   5 from os import listdir
   6 from os.path import join
   7 from threading import Thread, Lock
   8 from select import select
   9 from Queue import Queue, Empty
  10
  11 import openerp
  12 import openerp.addons.hw_proxy.controllers.main as hw_proxy
  13 from openerp import http
  14 from openerp.http import request
  15 from openerp.tools.translate import _
  16
  17 _logger = logging.getLogger(__name__)
  18
  19 try:
  20     import evdev
  21 except ImportError:
  22     _logger.error('OpenERP module hw_scanner depends on the evdev python module')
  23     evdev = None
  24
  25
  26 class Scanner(Thread):
  27     def __init__(self):
  28         Thread.__init__(self)
  29         self.lock = Lock()
  30         self.status = {'status':'connecting', 'messages':[]}
  31         self.input_dir = '/dev/input/by-id/'
  32         self.barcodes = Queue()
  33         self.keymap = {
  34             2: ("1","!"),
  35             3: ("2","@"),
  36             4: ("3","#"),
  37             5: ("4","$"),
  38             6: ("5","%"),
  39             7: ("6","^"),
  40             8: ("7","&"),
  41             9: ("8","*"),
  42             10:("9","("),
  43             11:("0",")"),
  44             12:("-","_"),
  45             13:("=","+"),
  46             # 14 BACKSPACE
  47             # 15 TAB
  48             16:("q","Q"),
  49             17:("w","W"),
  50             18:("e","E"),
  51             19:("r","R"),
  52             20:("t","T"),
  53             21:("y","Y"),
  54             22:("u","U"),
  55             23:("i","I"),
  56             24:("o","O"),
  57             25:("p","P"),
  58             26:("[","{"),
  59             27:("]","}"),
  60             # 28 ENTER
  61             # 29 LEFT_CTRL
  62             30:("a","A"),
  63             31:("s","S"),
  64             32:("d","D"),
  65             33:("f","F"),
  66             34:("g","G"),
  67             35:("h","H"),
  68             36:("j","J"),
  69             37:("k","K"),
  70             38:("l","L"),
  71             39:(";",":"),
  72             40:("'","\""),
  73             41:("`","~"),
  74             # 42 LEFT SHIFT
  75             43:("\\","|"),
  76             44:("z","Z"),
  77             45:("x","X"),
  78             46:("c","C"),
  79             47:("v","V"),
  80             48:("b","B"),
  81             49:("n","N"),
  82             50:("m","M"),
  83             51:(",","<"),
  84             52:(".",">"),
  85             53:("/","?"),
  86             # 54 RIGHT SHIFT
  87             57:(" "," "),
  88         }
  89
  90     def lockedstart(self):
  91         self.lock.acquire()
  92         if not self.isAlive():
  93             self.start()
  94         self.lock.release()
  95
  96     def set_status(self, status, message = None):
  97         if status == self.status['status']:
  98             if message != None and message != self.status['messages'][-1]:
  99                 self.status['messages'].append(message)
 100         else:
 101             self.status['status'] = status
 102             if message:
 103                 self.status['messages'] = [message]
 104             else:
 105                 self.status['messages'] = []
 106
 107         if status == 'error' and message:
 108             _logger.error('Barcode Scanner Error: '+message)
 109         elif status == 'disconnected' and message:
 110             _logger.warning('Disconnected Barcode Scanner: '+message)
 111
 112     def get_device(self):
 113         try:
 114             if not evdev:
 115                 return None
 116             devices   = [ device for device in listdir(self.input_dir)]
 117             keyboards = [ device for device in devices if ('kbd' in device) and ('keyboard' not in device.lower())]
 118             scanners  = [ device for device in devices if ('barcode' in device.lower()) or ('scanner' in device.lower())]
 119             if len(scanners) > 0:
 120                 self.set_status('connected','Connected to '+scanners[0])
 121                 return evdev.InputDevice(join(self.input_dir,scanners[0]))
 122             elif len(keyboards) > 0:
 123                 self.set_status('connected','Connected to '+keyboards[0])
 124                 return evdev.InputDevice(join(self.input_dir,keyboards[0]))
 125             else:
 126                 self.set_status('disconnected','Barcode Scanner Not Found')
 127                 return None
 128         except Exception as e:
 129             self.set_status('error',str(e))
 130             return None
 131
 132     @http.route('/hw_proxy/Vis_scanner_connected', type='json', auth='none', cors='*')
 133     def is_scanner_connected(self):
 134         return self.get_device() != None
 135
 136     def get_barcode(self):
 137         """ Returns a scanned barcode. Will wait at most 5 seconds to get a barcode, and will
 138             return barcode scanned in the past if they are not older than 5 seconds and have not
 139             been returned before. This is necessary to catch barcodes scanned while the POS is
 140             busy reading another barcode
 141         """
 142
 143         self.lockedstart()
 144
 145         while True:
 146             try:
 147                 timestamp, barcode = self.barcodes.get(True, 5)
 148                 if timestamp > time.time() - 5:
 149                     return barcode
 150             except Empty:
 151                 return ''
 152
 153     def get_status(self):
 154         self.lockedstart()
 155         return self.status
 156
 157     def run(self):
 158         """ This will start a loop that catches all keyboard events, parse barcode
 159             sequences and put them on a timestamped queue that can be consumed by
 160             the point of sale's requests for barcode events
 161         """
 162
 163         self.barcodes = Queue()
 164
 165         barcode  = []
 166         shift    = False
 167         device   = None
 168
 169         while True: # barcodes loop
 170             if device:  # ungrab device between barcodes and timeouts for plug & play
 171                 try:
 172                     device.ungrab()
 173                 except Exception as e:
 174                     self.set_status('error',str(e))
 175             device = self.get_device()
 176             if not device:
 177                 time.sleep(5)   # wait until a suitable device is plugged
 178             else:
 179                 try:
 180                     device.grab()
 181                     shift = False
 182                     barcode = []
 183
 184                     while True: # keycode loop
 185                         r,w,x = select([device],[],[],5)
 186                         if len(r) == 0: # timeout
 187                             break
 188                         events = device.read()
 189
 190                         for event in events:
 191                             if event.type == evdev.ecodes.EV_KEY:
 192                                 #_logger.debug('Evdev Keyboard event %s',evdev.categorize(event))
 193                                 if event.value == 1: # keydown events
 194                                     if event.code in self.keymap:
 195                                         if shift:
 196                                             barcode.append(self.keymap[event.code][1])
 197                                         else:
 198                                             barcode.append(self.keymap[event.code][0])
 199                                     elif event.code == 42 or event.code == 54: # SHIFT
 200                                         shift = True
 201                                     elif event.code == 28: # ENTER, end of barcode
 202                                         self.barcodes.put( (time.time(),''.join(barcode)) )
 203                                         barcode = []
 204                                 elif event.value == 0: #keyup events
 205                                     if event.code == 42 or event.code == 54: # LEFT SHIFT
 206                                         shift = False
 207
 208                 except Exception as e:
 209                     self.set_status('error',str(e))
 210
 211 s = Scanner()
 212
 213 hw_proxy.drivers['scanner'] = s
 214
 215 class ScannerDriver(hw_proxy.Proxy):
 216     @http.route('/hw_proxy/scanner', type='json', auth='none', cors='*')
 217     def scanner(self):
 218         return s.get_barcode()
 219
 220