4 from select import select
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
15 class VendingException(Exception): pass
18 def __init__(self, rfh, wfh):
20 self.secret = 'AAAAAAAAAAAAAAAA'
24 # Initialise ourselves into a known state
27 self.wfh.write('echo off\n')
29 self.wfh.write('PING\n')
32 code = self.get_response()[0]
35 def await_prompt(self):
44 print "Blah, seems DEC server has fallen over"
45 raise VendingException('failed to read input from vending machine')
46 if s == '': raise VendingException('nothing read!')
47 if s == '\n' or s == '\r':
50 if (s == '#' or s == '%') and state == 1: state = 2
51 if s == ' ' and state == 2:
55 if re.search('^[0-9a-fA-F]{4}$', prefix):
56 self.challenge = int(prefix, 16)
59 def get_response(self, async = False):
64 s = self.rfh.readline()
65 if s == '': return None
69 if code in asynchronous_responses:
70 self.handle_event(code, text)
76 def get_switches(self):
78 (code, text) = self.get_response()
80 return (False, code, text)
81 self.interpret_switches(text)
82 return (True, code, text)
84 def interpret_switches(self, text):
85 self.switches = (int(text[0:2], 16) << 8) | int(text[3:5], 16)
87 def handle_event(self, code, text):
89 self.events.append((DOOR, 0))
91 self.events.append((DOOR, 1))
93 self.events.append((SWITCH, None))
94 self.interpret_switches(text)
96 self.events.append((KEY, int(code[1:3])))
98 sys.stderr.write('WARNING: Unhandled event! (%s %s)\n'%(code,text))
100 def authed_message(self, message):
101 if self.challenge == None:
103 crc = do_crc('%c%c'%(self.challenge >> 8, self.challenge & 0xff))
104 crc = do_crc(self.secret, crc)
105 crc = do_crc(message, crc)
106 return message+'|'+('%04x'%crc)
109 self.wfh.write('PING\n')
110 (code, string) = self.get_response()
111 return (code == '000', code, string)
113 def vend(self, item):
114 if not re.search('^[0-9][0-9]$', item):
115 return (False, 'Invalid item requested (%s)'%item)
116 self.wfh.write(self.authed_message(('V%s\n'%item)+'\n'))
117 (code, string) = self.get_response()
118 return (code == '100', code, string)
120 def beep(self, duration = None, synchronous = True):
122 if synchronous: msg += 'S'
124 if duration > 255: duration = 255
125 if duration < 1: duration = 1
126 msg += '%02x'%duration
127 self.wfh.write(msg+'\n')
128 (code, string) = self.get_response()
129 return (code == '500', code, string)
131 def silence(self, duration = None, synchronous = True):
133 if synchronous: msg += 'S'
135 if duration > 255: duration = 255
136 if duration < 1: duration = 1
137 msg += '%02x'%duration
138 self.wfh.write(msg+'\n')
139 (code, string) = self.get_response()
140 return (code == '501', code, string)
142 def display(self, string):
144 string = string[0:10]
145 self.wfh.write('D'+string+'\n')
146 (code, string) = self.get_response()
147 return (code == '300', code, string)
149 def next_event(self, timeout = None):
150 # we don't want to buffer in the serial port, so we get all the events
152 if len(self.events) > 0: timeout = 0
154 (r, _, _) = select([self.rfh], [], [], timeout)
156 self.get_response(async = True)
160 if len(self.events) == 0: return None