#!/usr/local/bin/python # Fig. 23.16: viewCart.py # Generate XML representing cart, convert # to required format using browser-specific XSLT # style sheet and display results. import sys import Session from xml.xslt import Processor from xml.dom.DOMImplementation import implementation # load Session try: session = Session.Session() except Session.SessionError, message: # invalid/no session ID Session.redirect( "error.py?message=%s" % message ) sys.exit() cart = session.data[ "cart" ] total = 0 # total for all ordered items # generate XML representing cart object document = implementation.createDocument( None, None, None ) cartNode = document.createElement( "cart" ) document.appendChild( cartNode ) # add XML representation for each cart item for cartItem in cart.values(): # get book data, calculate subtotal and total book = cartItem.item
session = None # Session not yet created
# attempt to create Session three times
for i in range( 3 ):
# create new Session
try:
session = Session.Session( 1 )
# ID already exists
except Session.IDError:
time.sleep( 0.1 ) # wait 0.1 seconds -- try again
# missing content type
except Session.SessionError, message:
Session.redirect( "error.py?message=%s" % message )
sys.exit()
else:
break # Session created successfully
# if successful, save Session and re-direct to allBooks.py
if session:
nextPage = "allBooks.py?ID=%s" % session.data[ "ID" ]
session.saveSession()
Session.redirect( nextPage )
else:
Session.redirect( "error.py?message=Unable+to+create+Session" )
##########################################################################
# (C) Copyright 2002 by Deitel & Associates, Inc. and Prentice Hall. #
# Fig. 23.12: displayBook.py
# Retrieve one book's XML representation, convert
# to required format using browser-specific XSLT
# stylesheet and display results.
import cgi
import sys
import Session
from xml.xslt import Processor
from xml.dom.DOMImplementation import implementation
form = cgi.FieldStorage()
# ISBN has not been specified
if not form.has_key( "isbn" ):
Session.redirect( "error.py?message=No+ISBN+given" )
sys.exit()
# load Session
try:
session = Session.Session()
except Session.SessionError, message: # invalid/no session ID
Session.redirect( "error.py?message=%s" % message )
sys.exit()
titles = session.data[ "titles" ] # get titles
session.data[ "bookToAdd" ] = None # book has not been found
# locate Book object for selected book
for book in titles:
