Perl-Based HTML Exercise

Objective: Modify the statemach.cgi example from the previous lesson to use the htmlp() routine.

1. Review the baseline statemach.cgi code listed below.
2. Refactor the output logic so it is routed through htmlp() (instead of printing raw HTML fragments directly).
3. Paste your updated source code into the input area and click Submit.

Baseline: statemach.cgi (starter code)

#!/usr/bin/perl
# statemach.cgi
# a simple state-machine example

# constants
$CRLF = "\x0d\x0a";
$servername = $ENV{'SERVER_NAME'};  # this server
$scriptname = $ENV{'SCRIPT_NAME'};  # this program's URI
# how to call back
$callback = "http://$servername$scriptname";

# need this at the top of all CGI progs
print "Content-type: text/html$CRLF$CRLF";

# get the query vars, if any
%query = getquery();

# if there's no data, assume this is the first iteration
$state = 'first' unless %query;

# make variables from query hash
while(($qname, $qvalue) = each %query)
  { $$qname = $qvalue; }

# the main jump table
if    ($state eq 'first'   ) { first()    }
elsif ($state eq 'validate') { validate() }
else                         { unknown()  }

exit;

# STATE SCREENS

sub first
{
print <<FIRST;
<title>First Time</title>
<h1>Is this your first time?</h1>

<form method=POST action="$scriptname">

<p> This is your first time through the state-machine.

<p> Are you having fun yet?

<input type=checkbox name=fun>
<input type=hidden name=state value=validate>
<input type=submit value=" tell me about it ">

</form>

</html>
FIRST
}

sub validate{
if ($fun) { isfun() }
else { notfun() }
}

sub isfun{
print <<ISFUN;

<title>Having Fun</title>

<h1>Glad you are having fun!</h1>

ISFUN
}

sub notfun{
print <<NOTFUN;
<title>Sorry</title>

<h1>Sorry, that's the wrong answer</h1>

<h3>Come back when you are having fun!</h3>

NOTFUN
}

sub unknown{
print <<UNK
<title>Huh?</title>

<h1>Error: Confused</h1>

<p> Um...I do not know how I got here. Sorry.

UNK
}

# UTILITY ROUTINES

# getquery
# returns hash of CGI query strings
sub getquery{
my $method = $ENV{'REQUEST_METHOD'};
my ($query_string, $pair);
my %query_hash;

$query_string = $ENV{'QUERY_STRING'} if $method eq 'GET';
$query_string = <STDIN> if $method eq 'POST';
return undef unless $query_string;

foreach $pair (split(/&/, $query_string)) {
  $pair =~ s/\+/ /g;
  $pair =~ s/%([\da-f]{2})/pack('c',hex($1))/ieg;
  ($_qsname, $_qsvalue) = split(/=/, $pair);
  $query_hash{$_qsname} = $_qsvalue;
  }
return %query_hash;
}
# printvars
# diagnostic to print the environment and CGI variables
sub printvars{
print "<p>Environment:<br>\n";
foreach $e (sort keys %ENV) {
  print "<br><tt>$e => $ENV{$e}</tt>\n";
  }

print "<p>Form Vars:<br>\n";
foreach $name (sort keys %query) {
  print "<br><tt>$name => [$query{$name}]</tt>\n"; }

}

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Submit your updated source code

Paste your updated statemach.cgi source below. Your submission will be trimmed only at the beginning and end.

Your source code:

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