#!/usr/bin/perl -Tw
#++
# multi-page.cgi
#
# For Dalhousie CS 4173 (Web-centric Computing)
# Author: J. Blustein
# Created: 31 Oct 2001
# Last Modified: 18 June 2003
#
# Simplistic demonstration of saving state with hidden fields in forms
# See also
# * time1.cgi (saving state in visible radio buttons)
# * loan.cgi (a more elegant and complex example) by Lincoln Stein
# * SessionTrack servlet
#--
use CGI qw(:standard :Carp);
use CGI::Carp 'fatalsToBrowser';
use diagnostics; # verbose error messages
use strict; # check for mistakes
$| = 1; # flush output after each output statement
$\ = "\n"; # include \n at end of all output statements
use constant ME => '/~jamie/cgi-bin/4173/form/multi-page.cgi';
use constant DEFAULT_METHOD => 'post';
## about ME ##
# note that the form is submitted using a relative URL
# if the URL is absolute
# then it should be submitted to borg.cs.dal.ca *not* www.cs.dal.ca
#
# The Gory Details
#
# 1. Undergraduate webpages are all hosted on borg so any requests sent to
# www.cs.dal.ca will be redirected by the server to borg.cs.dal.ca
# (with one of the HTTP 3xx Redirection status messages) *but* neither
# Netscape (versions 4.7 and 6) nor Internet Explorer (version 5) will
# send the method="post" data to the new URL!
#
# 2. Internet Explorer (version 5) has an option to warn the user that
# the data they are submitting in a form is not going to the URL
# that was specified in the form, but that option does not seem to
# do anything.
##
# get parameter values from the submitted form, or use default values
my $name = param('name') || "";
my $colour = param('colour') || "";
my $method = param('m') || DEFAULT_METHOD;
##direction##
# which page is displayed next depends on which button was used to submit
# the form. $direction is + for forward buttons, and - for backwards
# buttons
my $direction = param('d') || "+";
$direction = "+" if $direction eq '>>>';
$direction = "+" if $direction eq 'Submit';
$direction = "-" if $direction eq '<<<';
##next_page##
# we read the page number from the hidden field and apply $direction to
# decide which page to display next
my $page = param('p') || 0;
$page = next_page($page, $direction);
# HTML output begins here
if (1 == $page) {
page_1($name,$colour,$method,ME);
} elsif (2 == $page) {
page_2($name,$colour,$method,ME);
} elsif (3 == $page) {
page_3($name,$colour,$method,ME);
} elsif (4 == $page) {
print header, XHTMLhead(),
"
Multi-page Form Example: Page 4
\n",
"
Goodbye!
", XHTMLtail();
} else {
die("impossible value `",$page,"' for \$page");
}
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
sub next_page() {
my ($page, $direction) = @_;
my $next;
return 1 if "" eq $direction;
die "impossible direction `", $direction, "'" if ($direction !~ /[-+]/);
$next = $page + (("+" eq $direction) ?+1 :-1);
return $next;
} # next_page()
sub XHTMLhead() {
return <<'EOH'
Multi-page Dynamic Form Example for Dal CS 4173 : Web-centric Computing
