/[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 1.2 - (hide annotations) (download) (as text)
Fri Jun 25 16:40:56 2004 UTC (17 years ago) by dagobah
Branch: MAIN
Changes since 1.1: +48 -5 lines
File MIME type: text/x-python
Start of asynchronous support - reading database & vending machine simultaneously

1 dagobah 1.2 import re, pg
2 dagobah 1.1 from CRC import do_crc
3 dagobah 1.2 from select import select
4 dagobah 1.1
5     asynchronous_responses = [ '400', '401', # door open/closed
6     '610', # switches changed
7 dagobah 1.2 '200', '201', '202', '203', '204', '205', '206',
8     '207', '208', '209', '211', # key presses
9 dagobah 1.1 ]
10 dagobah 1.2 DOOR = 1
11     SWITCH = 2
12     KEY = 3
13 dagobah 1.1
14     class VendingMachine:
15     def __init__(self, rfh, wfh):
16 dagobah 1.2 self.events = []
17 dagobah 1.1 self.secret = 'AAAAAAAAAAAAAAAA'
18     self.rfh = rfh
19     self.wfh = wfh
20     self.challenge = None
21     # Initialise ourselves into a known state
22     self.wfh.write('\n')
23     self.await_prompt()
24     self.wfh.write('echo off\n')
25     self.await_prompt()
26     self.wfh.write('PING\n')
27     code = ''
28     while code != '000':
29     (code, _) = self.get_response()
30 dagobah 1.2 self.get_switches()
31 dagobah 1.1
32     def await_prompt(self):
33     self.wfh.flush()
34     state = 1
35     prefix = ''
36     s = ''
37     while True:
38     s = self.rfh.read(1)
39     if s == '': raise Exception
40     if s == '\n' or s == '\r':
41     state = 1
42     prefix = ''
43     if (s == '#' or s == '%') and state == 1: state = 2
44     if s == ' ' and state == 2:
45     if prefix == '':
46     self.challenge = None
47     return
48     if re.search('^[0-9a-fA-F]{4}$', prefix):
49 dagobah 1.2 self.challenge = int(prefix, 16)
50 dagobah 1.1 return
51    
52     def get_response(self):
53     self.wfh.flush()
54     while True:
55     s = ''
56     while s == '':
57     s = self.rfh.readline()
58     if s == '': return None
59     s = s.strip('\r\n')
60     code = s[0:3]
61     text = s[4:]
62     if code in asynchronous_responses:
63     self.handle_event(code, text)
64     else:
65     self.await_prompt()
66     return (code, text)
67    
68 dagobah 1.2 def get_switches(self):
69     self.wfh.write('S\n')
70     (code, text) = self.get_response()
71     if code != '600':
72     return (False, code, text)
73     self.interpret_switches(text)
74     return (True, code, text)
75    
76     def interpret_switches(self, text):
77     self.switches = (int(text[0:2], 16) << 8) | int(text[3:5], 16)
78    
79 dagobah 1.1 def handle_event(self, code, text):
80 dagobah 1.2 if code == '400':
81     self.events.append((DOOR, 0))
82     elif code == '401':
83     self.events.append((DOOR, 1))
84     elif code == '610':
85     self.events_append((SWITCH, None))
86     self.interpret_switches(text)
87     elif code[0] == '2':
88     self.events.append((KEY, int(code[1:3])))
89     else:
90     sys.stderr.write('WARNING: Unhandled event! (%s %s)\n'%(code,text))
91 dagobah 1.1
92     def authed_message(self, message):
93     if self.challenge == None:
94     return message
95     crc = do_crc('%c%c'%(self.challenge >> 8, self.challenge & 0xff))
96     crc = do_crc(self.secret, crc)
97     crc = do_crc(message, crc)
98     return message+'|'+('%04x'%crc)
99    
100     def ping(self):
101     self.wfh.write('PING\n')
102     (code, string) = self.get_response()
103     return (code == '000', code, string)
104    
105     def vend(self, item):
106     if not re.search('^[0-9][0-9]$', item):
107     return (False, 'Invalid item requested (%s)'%item)
108     self.wfh.write(self.authed_message(('V%s\n'%item)+'\n'))
109     (code, string) = self.get_response()
110 dagobah 1.2 return (code == '100', code, string)
111 dagobah 1.1
112     def beep(self, duration = None, synchronous = True):
113     msg = 'B'
114     if synchronous: msg += 'S'
115     if duration != None:
116     if duration > 255: duration = 255
117     if duration < 1: duration = 1
118     msg += '%02x'%duration
119     self.wfh.write(msg+'\n')
120     (code, string) = self.get_response()
121     return (code == '500', code, string)
122    
123     def silence(self, duration = None, synchronous = True):
124     msg = 'C'
125     if synchronous: msg += 'S'
126     if duration != None:
127     if duration > 255: duration = 255
128     if duration < 1: duration = 1
129     msg += '%02x'%duration
130     self.wfh.write(msg+'\n')
131     (code, string) = self.get_response()
132     # FIXME: workaround a bug in rom W. should be just: return (code == '500', code, string)
133     return (code == '500' or code == '501', code, string)
134    
135     def display(self, string):
136     if len(string) > 10:
137     string = string[0:10]
138     self.wfh.write('D'+string+'\n')
139     (code, string) = self.get_response()
140     return (code == '300', code, string)
141    
142 dagobah 1.2 def next_event(self):
143     if len(self.events) > 0:
144     ret = self.events[0]
145     del self.events[0]
146     return ret
147     return None
148    
149     def wait_for_events(self, timeout = None):
150     (r, _, _) = select([self.rfh], [], [], timeout)
151     if not r: return False
152     event_added = False
153     while True:
154     r.get_response()
155     (r, _, _) = select([self.rfh], [], [], 0)
156     if not r: return event_added

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