/[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 1.12 - (show annotations) (download) (as text)
Sun Aug 1 08:21:01 2004 UTC (16 years, 10 months ago) by cameron
Branch: MAIN
Changes since 1.11: +2 -3 lines
File MIME type: text/x-python
death to stderr and print statements!

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 == '\n' or s == '\r':
48 state = 1
49 prefix = ''
50 if (s == '#' or s == '%') and state == 1: state = 2
51 if s == ' ' and state == 2:
52 if prefix == '':
53 self.challenge = None
54 return
55 if re.search('^[0-9a-fA-F]{4}$', prefix):
56 self.challenge = int(prefix, 16)
57 return
58
59 def get_response(self, async = False):
60 self.wfh.flush()
61 while True:
62 s = ''
63 while s == '':
64 s = self.rfh.readline()
65 if s == '':
66 raise VendingException('Input socket has closed!')
67 s = s.strip('\r\n')
68 code = s[0:3]
69 text = s[4:]
70 if code in asynchronous_responses:
71 self.handle_event(code, text)
72 if async: return None
73 else:
74 self.await_prompt()
75 return (code, text)
76
77 def get_switches(self):
78 self.wfh.write('S\n')
79 (code, text) = self.get_response()
80 if code != '600':
81 return (False, code, text)
82 self.interpret_switches(text)
83 return (True, code, text)
84
85 def interpret_switches(self, text):
86 self.switches = (int(text[0:2], 16) << 8) | int(text[3:5], 16)
87
88 def handle_event(self, code, text):
89 if code == '400':
90 self.events.append((DOOR, 0))
91 elif code == '401':
92 self.events.append((DOOR, 1))
93 elif code == '610':
94 self.events.append((SWITCH, None))
95 self.interpret_switches(text)
96 elif code[0] == '2':
97 self.events.append((KEY, int(code[1:3])))
98 else:
99 logging.warning('Unhandled event! (%s %s)\n'%(code,text))
100
101 def authed_message(self, message):
102 if self.challenge == None:
103 return message
104 crc = do_crc('%c%c'%(self.challenge >> 8, self.challenge & 0xff))
105 crc = do_crc(self.secret, crc)
106 crc = do_crc(message, crc)
107 return message+'|'+('%04x'%crc)
108
109 def ping(self):
110 self.wfh.write('PING\n')
111 (code, string) = self.get_response()
112 return (code == '000', code, string)
113
114 def vend(self, item):
115 if not re.search('^[0-9][0-9]$', item):
116 return (False, 'Invalid item requested (%s)'%item)
117 self.wfh.write(self.authed_message(('V%s\n'%item)+'\n'))
118 (code, string) = self.get_response()
119 return (code == '100', code, string)
120
121 def beep(self, duration = None, synchronous = True):
122 msg = 'B'
123 if synchronous: msg += 'S'
124 if duration != None:
125 if duration > 255: duration = 255
126 if duration < 1: duration = 1
127 msg += '%02x'%duration
128 self.wfh.write(msg+'\n')
129 (code, string) = self.get_response()
130 return (code == '500', code, string)
131
132 def silence(self, duration = None, synchronous = True):
133 msg = 'C'
134 if synchronous: msg += 'S'
135 if duration != None:
136 if duration > 255: duration = 255
137 if duration < 1: duration = 1
138 msg += '%02x'%duration
139 self.wfh.write(msg+'\n')
140 (code, string) = self.get_response()
141 return (code == '501', code, string)
142
143 def display(self, string):
144 if len(string) > 10:
145 string = string[0:10]
146 self.wfh.write('D'+string+'\n')
147 (code, string) = self.get_response()
148 return (code == '300', code, string)
149
150 def next_event(self, timeout = None):
151 # we don't want to buffer in the serial port, so we get all the events
152 # we can ASAP.
153 if len(self.events) > 0: timeout = 0
154 while True:
155 (r, _, _) = select([self.rfh], [], [], timeout)
156 if r:
157 self.get_response(async = True)
158 timeout = 0
159 else:
160 break
161 if len(self.events) == 0: return None
162 ret = self.events[0]
163 del self.events[0]
164 return ret

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