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