sql-edition/servers/VendServer.py

   1 #!/usr/bin/python
   2
   3 import sys, os, string, socket, time, re
   4 import pg
   5 from LATClient import LATClient
   6 from VendingMachine import VendingMachine
   7
   8 class DispenseDatabase:
   9         def __init__(self, vending_machine):
  10                 self.vending_machine = vending_machine
  11                 self.db = pg.DB(dbname = 'dispense', host = 'dispense.ucc.gu.uwa.edu.au', user = 'vendserver', passwd = 'revresdnev')
  12                 self.db.query('LISTEN vend_requests')
  13
  14         def process_requests(self):
  15                 print 'processing'
  16                 query = 'SELECT request_id, request_slot FROM vend_requests WHERE request_handled = false'
  17                 try:
  18                         outstanding = self.db.query(query).getresult()
  19                 except (pg.error,), db_err:
  20                         sys.stderr.write('Failed to query database: %s\n'%(db_err.strip()))
  21                         return
  22                 for (id, slot) in outstanding:
  23                         (worked, code, string) = self.vending_machine.vend(slot)
  24                         print (worked, code, string)
  25                         if worked:
  26                                 query = 'SELECT vend_success(%s)'%id
  27                                 self.db.query(query).getresult()
  28                         else:
  29                                 query = 'SELECT vend_failed(%s)'%id
  30                                 self.db.query(query).getresult()
  31
  32         def handle_events(self):
  33                 notifier = self.db.getnotify()
  34                 while notifier is not None:
  35                         self.process_requests()
  36                         notify = self.db.getnotify()
  37
  38 if __name__ == '__main__':
  39         # Open vending machine via LAT
  40         latclient = LATClient(service = 'VEND', password = 'dmscptd')
  41         (rfh, wfh) = latclient.get_fh()
  42         v = VendingMachine(rfh, wfh)
  43         print 'PING is', v.ping()
  44         #print 'BEEP is', v.beep()
  45         #print 'VEND 11 is', v.vend('11')
  46         #print 'SILENCE is', v.silence()
  47         #print 'DISPLAY is', v.display('WELCOME')
  48         print 'S is', v.get_switches()
  49
  50         db = DispenseDatabase(v)
  51         db.process_requests()
  52         while True:
  53                 v.wait_for_events(1)
  54                 db.handle_events()