sql-edition/servers/VendingMachine.py

   1 # vim:ts=4
   2 import re
   3 from CRC import do_crc
   4 from select import select
   5 import socket, logging
   6 from time import time, sleep
   7
   8 asynchronous_responses = [      '400', '401', # door open/closed
   9                                 '610',        # switches changed
  10                                 '200', '201', '202', '203', '204', '205', '206',
  11                                 '207', '208', '209', '211', # key presses
  12                          ]
  13 DOOR = 1
  14 SWITCH = 2
  15 KEY = 3
  16 TICK = 4
  17
  18 class VendingException(Exception): pass
  19
  20 class VendingMachine:
  21         def __init__(self, rfh, wfh):
  22                 self.events = []
  23                 # Secret
  24                 self.secret = 'SN4CKZ0RZZZZZZZZ'
  25                 self.rfh = rfh
  26                 self.wfh = wfh
  27                 self.challenge = None
  28                 # Initialise ourselves into a known state
  29                 self.wfh.write('\n')
  30                 self.await_prompt()
  31                 self.wfh.write('echo off\n')
  32                 self.await_prompt()
  33                 self.wfh.write('PING\n')
  34                 code = ''
  35                 while code != '000':
  36                         code = self.get_response()[0]
  37                 self.get_switches()
  38
  39         def await_prompt(self):
  40                 self.wfh.flush()
  41                 state = 1
  42                 prefix = ''
  43                 s = ''
  44                 while True:
  45                         try:
  46                                 s = self.rfh.read(1)
  47                         except socket.error:
  48                                 raise VendingException('failed to read input from vending machine')
  49                         if s == '': raise VendingException('nothing read!')
  50                         if (s != '#' and s != '%') and state == 1: prefix += s
  51                         if s == '\n' or s == '\r':
  52                                 state = 1
  53                                 prefix = ''
  54                         if (s == '#' or s == '%') and state == 1: state = 2
  55                         if s == ' ' and state == 2:
  56                                 if prefix == '':
  57                                         self.challenge = None
  58                                         return
  59                                 if re.search('^[0-9a-fA-F]{4}$', prefix):
  60                                         self.challenge = int(prefix, 16)
  61                                         return
  62
  63         def get_response(self, async = False):
  64                 self.wfh.flush()
  65                 while True:
  66                         s = ''
  67                         while s == '':
  68                                 s = self.rfh.readline()
  69                                 if s == '':
  70                                         raise VendingException('Input socket has closed!')
  71                                 s = s.strip('\r\n')
  72                         code = s[0:3]
  73                         text = s[4:]
  74                         if code in asynchronous_responses:
  75                                 self.handle_event(code, text)
  76                                 if async: return None
  77                         else:
  78                                 self.await_prompt()
  79                                 return (code, text)
  80
  81         def get_switches(self):
  82                 self.wfh.write('S\n')
  83                 (code, text) = self.get_response()
  84                 if code != '600':
  85                         return (False, code, text)
  86                 self.interpret_switches(text)
  87                 return (True, code, text)
  88
  89         def interpret_switches(self, text):
  90                 self.switches = (int(text[0:2], 16) << 8) | int(text[3:5], 16)
  91
  92         def handle_event(self, code, text):
  93                 if code == '400':
  94                         self.events.append((DOOR, 1))
  95                 elif code == '401':
  96                         self.events.append((DOOR, 0))
  97                 elif code == '610':
  98                         # NOP this. Nothing handles this yet.
  99                         #self.events.append((SWITCH, None))
 100                         self.interpret_switches(text)
 101                 elif code[0] == '2':
 102                         self.events.append((KEY, int(code[1:3])))
 103                 else:
 104                         logging.warning('Unhandled event! (%s %s)\n'%(code,text))
 105
 106         def authed_message(self, message):
 107                 if self.challenge == None:
 108                         return message
 109                 crc = do_crc('%c%c'%(self.challenge >> 8, self.challenge & 0xff))
 110                 crc = do_crc(self.secret, crc)
 111                 crc = do_crc(message, crc)
 112                 return message+'|'+('%04x'%crc)
 113
 114         def ping(self):
 115                 self.wfh.write('PING\n')
 116                 (code, string) = self.get_response()
 117                 return (code == '000', code, string)
 118
 119         def vend(self, item):
 120                 if not re.search('^[0-9][0-9]$', item):
 121                         return (False, 'Invalid item requested (%s)'%item)
 122                 self.wfh.write(self.authed_message(('V%s'%item))+'\n')
 123                 (code, string) = self.get_response()
 124                 return (code == '100', code, string)
 125
 126         def beep(self, duration = None, synchronous = True):
 127                 msg = 'B'
 128                 if synchronous: msg += 'S'
 129                 if duration != None:
 130                         if duration > 255: duration = 255
 131                         if duration < 1: duration = 1
 132                         msg += '%02x'%duration
 133                 self.wfh.write(msg+'\n')
 134                 (code, string) = self.get_response()
 135                 return (code == '500', code, string)
 136
 137         def silence(self, duration = None, synchronous = True):
 138                 msg = 'C'
 139                 if synchronous: msg += 'S'
 140                 if duration != None:
 141                         if duration > 255: duration = 255
 142                         if duration < 1: duration = 1
 143                         msg += '%02x'%duration
 144                 self.wfh.write(msg+'\n')
 145                 (code, string) = self.get_response()
 146                 return (code == '501', code, string)
 147
 148         def display(self, string):
 149                 if len(string) > 10:
 150                         string = string[0:10]
 151                 string = re.sub('(.)\.', lambda match: '.'+match.group(1), string)
 152                 self.wfh.write('D'+string+'\n')
 153                 (code, string) = self.get_response()
 154                 return (code == '300', code, string)
 155
 156         def next_event(self, timeout = None):
 157                 # we don't want to buffer in the serial port, so we get all the events
 158                 # we can ASAP.
 159                 if timeout < 0: timeout = 0
 160                 if len(self.events) > 0: timeout = 0
 161                 while True:
 162                         (r, _, _) = select([self.rfh], [], [], timeout)
 163                         if r:
 164                                 self.get_response(async = True)
 165                                 timeout = 0
 166                         else:
 167                                 break
 168                 if len(self.events) == 0: return (TICK, time())
 169                 ret = self.events[0]
 170                 del self.events[0]
 171                 return ret