sql-edition/servers/VendingMachine.py

   1 import re, pg
   2 from CRC import do_crc
   3 from select import select
   4
   5 asynchronous_responses = [      '400', '401', # door open/closed
   6                                 '610',        # switches changed
   7                                 '200', '201', '202', '203', '204', '205', '206',
   8                                 '207', '208', '209', '211', # key presses
   9                          ]
  10 DOOR = 1
  11 SWITCH = 2
  12 KEY = 3
  13
  14 class VendingMachine:
  15         def __init__(self, rfh, wfh):
  16                 self.events = []
  17                 self.secret = 'AAAAAAAAAAAAAAAA'
  18                 self.rfh = rfh
  19                 self.wfh = wfh
  20                 self.challenge = None
  21                 # Initialise ourselves into a known state
  22                 self.wfh.write('\n')
  23                 self.await_prompt()
  24                 self.wfh.write('echo off\n')
  25                 self.await_prompt()
  26                 self.wfh.write('PING\n')
  27                 code = ''
  28                 while code != '000':
  29                         (code, _) = self.get_response()
  30                 self.get_switches()
  31
  32         def await_prompt(self):
  33                 self.wfh.flush()
  34                 state = 1
  35                 prefix = ''
  36                 s = ''
  37                 while True:
  38                         s = self.rfh.read(1)
  39                         if s == '': raise Exception
  40                         if s == '\n' or s == '\r':
  41                                 state = 1
  42                                 prefix = ''
  43                         if (s == '#' or s == '%') and state == 1: state = 2
  44                         if s == ' ' and state == 2:
  45                                 if prefix == '':
  46                                         self.challenge = None
  47                                         return
  48                                 if re.search('^[0-9a-fA-F]{4}$', prefix):
  49                                         self.challenge = int(prefix, 16)
  50                                         return
  51
  52         def get_response(self):
  53                 self.wfh.flush()
  54                 while True:
  55                         s = ''
  56                         while s == '':
  57                                 s = self.rfh.readline()
  58                                 if s == '': return None
  59                                 s = s.strip('\r\n')
  60                         code = s[0:3]
  61                         text = s[4:]
  62                         if code in asynchronous_responses:
  63                                 self.handle_event(code, text)
  64                         else:
  65                                 self.await_prompt()
  66                                 return (code, text)
  67
  68         def get_switches(self):
  69                 self.wfh.write('S\n')
  70                 (code, text) = self.get_response()
  71                 if code != '600':
  72                         return (False, code, text)
  73                 self.interpret_switches(text)
  74                 return (True, code, text)
  75
  76         def interpret_switches(self, text):
  77                 self.switches = (int(text[0:2], 16) << 8) | int(text[3:5], 16)
  78
  79         def handle_event(self, code, text):
  80                 if code == '400':
  81                         self.events.append((DOOR, 0))
  82                 elif code == '401':
  83                         self.events.append((DOOR, 1))
  84                 elif code == '610':
  85                         self.events_append((SWITCH, None))
  86                         self.interpret_switches(text)
  87                 elif code[0] == '2':
  88                         self.events.append((KEY, int(code[1:3])))
  89                 else:
  90                         sys.stderr.write('WARNING: Unhandled event! (%s %s)\n'%(code,text))
  91
  92         def authed_message(self, message):
  93                 if self.challenge == None:
  94                         return message
  95                 crc = do_crc('%c%c'%(self.challenge >> 8, self.challenge & 0xff))
  96                 crc = do_crc(self.secret, crc)
  97                 crc = do_crc(message, crc)
  98                 return message+'|'+('%04x'%crc)
  99
 100         def ping(self):
 101                 self.wfh.write('PING\n')
 102                 (code, string) = self.get_response()
 103                 return (code == '000', code, string)
 104
 105         def vend(self, item):
 106                 if not re.search('^[0-9][0-9]$', item):
 107                         return (False, 'Invalid item requested (%s)'%item)
 108                 self.wfh.write(self.authed_message(('V%s\n'%item)+'\n'))
 109                 (code, string) = self.get_response()
 110                 return (code == '100', code, string)
 111
 112         def beep(self, duration = None, synchronous = True):
 113                 msg = 'B'
 114                 if synchronous: msg += 'S'
 115                 if duration != None:
 116                         if duration > 255: duration = 255
 117                         if duration < 1: duration = 1
 118                         msg += '%02x'%duration
 119                 self.wfh.write(msg+'\n')
 120                 (code, string) = self.get_response()
 121                 return (code == '500', code, string)
 122
 123         def silence(self, duration = None, synchronous = True):
 124                 msg = 'C'
 125                 if synchronous: msg += 'S'
 126                 if duration != None:
 127                         if duration > 255: duration = 255
 128                         if duration < 1: duration = 1
 129                         msg += '%02x'%duration
 130                 self.wfh.write(msg+'\n')
 131                 (code, string) = self.get_response()
 132                 # FIXME: workaround a bug in rom W. should be just: return (code == '500', code, string)
 133                 return (code == '500' or code == '501', code, string)
 134
 135         def display(self, string):
 136                 if len(string) > 10:
 137                         string = string[0:10]
 138                 self.wfh.write('D'+string+'\n')
 139                 (code, string) = self.get_response()
 140                 return (code == '300', code, string)
 141
 142         def next_event(self):
 143                 if len(self.events) > 0:
 144                         ret = self.events[0]
 145                         del self.events[0]
 146                         return ret
 147                 return None
 148
 149         def wait_for_events(self, timeout = None):
 150                 (r, _, _) = select([self.rfh], [], [], timeout)
 151                 if not r: return False
 152                 event_added = False
 153                 while True:
 154                     r.get_response()
 155                     (r, _, _) = select([self.rfh], [], [], 0)
 156                     if not r: return event_added