From 01c3723145f0bfb635fea3c3a254859e396e3e2a Mon Sep 17 00:00:00 2001
From: Bernard Blackham <dagobah@ucc.gu.uwa.edu.au>
Date: Fri, 25 Jun 2004 16:40:56 +0000
Subject: [PATCH] Start of asynchronous support - reading database & vending
 machine simultaneously

---
 sql-edition/servers/VendServer.py     | 48 +++++++++++++++++++++---
 sql-edition/servers/VendingMachine.py | 53 ++++++++++++++++++++++++---
 2 files changed, 90 insertions(+), 11 deletions(-)

diff --git a/sql-edition/servers/VendServer.py b/sql-edition/servers/VendServer.py
index 3f806bc..c3f04bc 100755
--- 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
--- 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
-- 
2.20.1