#!/usr/bin/perl
###############
## Libraries ##
###############
use strict;
use warnings;
use JSON;
##################
## User-defined ##
##################
# This is a link to Google's publicly-available jQuery library
my $jquery = "ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js";
##################
## Main Program ##
##################
my $this_prog = $ENV{'REQUEST_URI'};
my $h_param = cgi_params();
if (exists $h_param->{'ajax'}) {
# If 'ajax' was sent in the URL, it's the client communicating
# with the Server via Ajax. See function ajax_query_server(),
# which initiates this. You could also put '?ajax' in the URL
# query to see the data results directly.
##
server_side_ajax();
} else {
# If the URL doesn't contain the key 'ajax', we display the HTML
# page normally.
##
print "Content-type: text/html\n\n";
print_javascript();
print_html_page();
}
#################
## Subroutines ##
#################
sub cgi_params {
my $query = $ENV{'QUERY_STRING'} || 0;
$query or return { };
my $h_params = { };
foreach my $key (split('&', $query)) {
my $val = ($key =~ s/=(.*)$//)? $1: undef;
$h_params->{$key} = $val;
}
return $h_params;
}
sub server_side_ajax {
# Calculate data somehow
my $a_data = [ ];
my $npoints = 16;
# For the sake of example, just randomize it for now
for (my $i = 0; $i < $npoints; $i++) {
my ($x, $y) = (int(rand(100)), int(rand(100)));
push @$a_data, [ $x, $y ];
}
my $h_json = { 'data' => $a_data };
# Print the JSON header and data
print "Content-type: application/json\n\n";
print to_json($h_json);
exit;
}
sub print_javascript {
# Send the jQuery/Javascript code to the browser
print qq{
};
}
sub print_html_page {
# Here's where the HTML body gets printed
print qq{
Ajax Data Example
};
}