/[anoncvs]/projects/dispense2/sql-edition/servers/VendingMachine.py


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Contents of /projects/dispense2/sql-edition/servers/VendingMachine.py

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Revision 1.13 - (show annotations) (download) (as text)
Sun Oct 31 09:29:05 2004 UTC (16 years, 7 months ago) by dagobah
Branch: MAIN
Changes since 1.12: +2 -1 lines
File MIME type: text/x-python
fix stupid crypto bug

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

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