sql-edition/servers/VendingMachine.py

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