/[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 - (hide 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 dagobah 1.4 # vim:ts=4
2 dagobah 1.7 import re
3 dagobah 1.1 from CRC import do_crc
4 dagobah 1.2 from select import select
5 cameron 1.12 import socket, logging
6 dagobah 1.1
7     asynchronous_responses = [ '400', '401', # door open/closed
8     '610', # switches changed
9 dagobah 1.2 '200', '201', '202', '203', '204', '205', '206',
10     '207', '208', '209', '211', # key presses
11 dagobah 1.1 ]
12 dagobah 1.2 DOOR = 1
13     SWITCH = 2
14     KEY = 3
15 dagobah 1.1
16 cameron 1.8 class VendingException(Exception): pass
17    
18 dagobah 1.1 class VendingMachine:
19     def __init__(self, rfh, wfh):
20 dagobah 1.2 self.events = []
21 dagobah 1.1 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 cameron 1.8 code = self.get_response()[0]
34 dagobah 1.2 self.get_switches()
35 dagobah 1.1
36     def await_prompt(self):
37     self.wfh.flush()
38     state = 1
39     prefix = ''
40     s = ''
41     while True:
42 cameron 1.8 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 dagobah 1.13 if (s != '#' and s != '%') and state == 1: prefix += s
48 dagobah 1.1 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 dagobah 1.2 self.challenge = int(prefix, 16)
58 dagobah 1.1 return
59    
60 dagobah 1.3 def get_response(self, async = False):
61 dagobah 1.1 self.wfh.flush()
62     while True:
63     s = ''
64     while s == '':
65     s = self.rfh.readline()
66 dagobah 1.9 if s == '':
67 cameron 1.10 raise VendingException('Input socket has closed!')
68 dagobah 1.1 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 dagobah 1.3 if async: return None
74 dagobah 1.1 else:
75     self.await_prompt()
76     return (code, text)
77    
78 dagobah 1.2 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 dagobah 1.1 def handle_event(self, code, text):
90 dagobah 1.2 if code == '400':
91     self.events.append((DOOR, 0))
92     elif code == '401':
93     self.events.append((DOOR, 1))
94     elif code == '610':
95 dagobah 1.4 self.events.append((SWITCH, None))
96 dagobah 1.2 self.interpret_switches(text)
97     elif code[0] == '2':
98     self.events.append((KEY, int(code[1:3])))
99     else:
100 cameron 1.12 logging.warning('Unhandled event! (%s %s)\n'%(code,text))
101 dagobah 1.1
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 dagobah 1.13 self.wfh.write(self.authed_message(('V%s'%item))+'\n')
119 dagobah 1.1 (code, string) = self.get_response()
120 dagobah 1.2 return (code == '100', code, string)
121 dagobah 1.1
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 dagobah 1.6 return (code == '501', code, string)
143 dagobah 1.1
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 dagobah 1.4 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 dagobah 1.2 while True:
156 dagobah 1.4 (r, _, _) = select([self.rfh], [], [], timeout)
157     if r:
158     self.get_response(async = True)
159 dagobah 1.5 timeout = 0
160 dagobah 1.4 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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