/[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 1.16 - (show annotations) (download) (as text)
Tue Apr 5 09:55:01 2005 UTC (16 years, 2 months ago) by mtearle
Branch: MAIN
Changes since 1.15: +3 -1 lines
File MIME type: text/x-python
more refactoring

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

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