Start of asynchronous support - reading database & vending machine simultaneously

diff --git a/sql-edition/servers/VendServer.py b/sql-edition/servers/VendServer.py
index 3f806bc..c3f04bc 100755 (executable)
--- a/sql-edition/servers/VendServer.py
+++ b/sql-edition/servers/VendServer.py
@@ -1,18 +1,54 @@
 #!/usr/bin/python
 
 import sys, os, string, socket, time, re
-from popen2 import popen2
-from pyPgSQL import PgSQL
+import pg
 from LATClient import LATClient
 from VendingMachine import VendingMachine
 
+class DispenseDatabase:
+       def __init__(self, vending_machine):
+               self.vending_machine = vending_machine
+               self.db = pg.DB(dbname = 'dispense', host = 'dispense.ucc.gu.uwa.edu.au', user = 'vendserver', passwd = 'revresdnev')
+               self.db.query('LISTEN vend_requests')
+
+       def process_requests(self):
+               print 'processing'
+               query = 'SELECT request_id, request_slot FROM vend_requests WHERE request_handled = false'
+               try:
+                       outstanding = self.db.query(query).getresult()
+               except (pg.error,), db_err:
+                       sys.stderr.write('Failed to query database: %s\n'%(db_err.strip()))
+                       return
+               for (id, slot) in outstanding:
+                       (worked, code, string) = self.vending_machine.vend(slot)
+                       print (worked, code, string)
+                       if worked:
+                               query = 'SELECT vend_success(%s)'%id
+                               self.db.query(query).getresult()
+                       else:
+                               query = 'SELECT vend_failed(%s)'%id
+                               self.db.query(query).getresult()
+
+       def handle_events(self):
+               notifier = self.db.getnotify()
+               while notifier is not None:
+                       self.process_requests()
+                       notify = self.db.getnotify()
+
 if __name__ == '__main__':
        # Open vending machine via LAT
        latclient = LATClient(service = 'VEND', password = 'dmscptd')
        (rfh, wfh) = latclient.get_fh()
        v = VendingMachine(rfh, wfh)
        print 'PING is', v.ping()
-       print 'BEEP is', v.beep()
-       print 'VEND 11 is', v.vend('11')
-       print 'SILENCE is', v.silence()
-       print 'DISPLAY is', v.display('GOOD NIGHT')
+       #print 'BEEP is', v.beep()
+       #print 'VEND 11 is', v.vend('11')
+       #print 'SILENCE is', v.silence()
+       #print 'DISPLAY is', v.display('WELCOME')
+       print 'S is', v.get_switches()
+
+       db = DispenseDatabase(v)
+       db.process_requests()
+       while True:
+               v.wait_for_events(1)
+               db.handle_events()

diff --git a/sql-edition/servers/VendingMachine.py b/sql-edition/servers/VendingMachine.py
index 3046360..2574c6d 100644 (file)
--- a/sql-edition/servers/VendingMachine.py
+++ b/sql-edition/servers/VendingMachine.py
@@ -1,13 +1,19 @@
-import re
+import re, pg
 from CRC import do_crc
-from binascii import unhexlify
+from select import select
 
 asynchronous_responses = [     '400', '401', # door open/closed
                                '610',        # switches changed
+                               '200', '201', '202', '203', '204', '205', '206',
+                               '207', '208', '209', '211', # key presses
                         ]
+DOOR = 1
+SWITCH = 2
+KEY = 3
 
 class VendingMachine:
        def __init__(self, rfh, wfh):
+               self.events = []
                self.secret = 'AAAAAAAAAAAAAAAA'
                self.rfh = rfh
                self.wfh = wfh
@@ -21,6 +27,7 @@ class VendingMachine:
                code = ''
                while code != '000':
                        (code, _) = self.get_response()
+               self.get_switches()
 
        def await_prompt(self):
                self.wfh.flush()
@@ -39,7 +46,7 @@ class VendingMachine:
                                        self.challenge = None
                                        return
                                if re.search('^[0-9a-fA-F]{4}$', prefix):
-                                       self.challenge = unhexlify(prefix)
+                                       self.challenge = int(prefix, 16)
                                        return
 
        def get_response(self):
@@ -58,8 +65,29 @@ class VendingMachine:
                                self.await_prompt()
                                return (code, text)
 
+       def get_switches(self):
+               self.wfh.write('S\n')
+               (code, text) = self.get_response()
+               if code != '600':
+                       return (False, code, text)
+               self.interpret_switches(text)
+               return (True, code, text)
+
+       def interpret_switches(self, text):
+               self.switches = (int(text[0:2], 16) << 8) | int(text[3:5], 16)
+
        def handle_event(self, code, text):
-               pass
+               if code == '400':
+                       self.events.append((DOOR, 0))
+               elif code == '401':
+                       self.events.append((DOOR, 1))
+               elif code == '610':
+                       self.events_append((SWITCH, None))
+                       self.interpret_switches(text)
+               elif code[0] == '2':
+                       self.events.append((KEY, int(code[1:3])))
+               else:
+                       sys.stderr.write('WARNING: Unhandled event! (%s %s)\n'%(code,text))
 
        def authed_message(self, message):
                if self.challenge == None:
@@ -79,7 +107,7 @@ class VendingMachine:
                        return (False, 'Invalid item requested (%s)'%item)
                self.wfh.write(self.authed_message(('V%s\n'%item)+'\n'))
                (code, string) = self.get_response()
-               return (code, string)
+               return (code == '100', code, string)
 
        def beep(self, duration = None, synchronous = True):
                msg = 'B'
@@ -111,3 +139,18 @@ class VendingMachine:
                (code, string) = self.get_response()
                return (code == '300', code, string)
 
+       def next_event(self):
+               if len(self.events) > 0:
+                       ret = self.events[0]
+                       del self.events[0]
+                       return ret
+               return None
+
+       def wait_for_events(self, timeout = None):
+               (r, _, _) = select([self.rfh], [], [], timeout)
+               if not r: return False
+               event_added = False
+               while True:
+                   r.get_response()
+                   (r, _, _) = select([self.rfh], [], [], 0)
+                   if not r: return event_added