use strict;
use HTTP::Request;
use IO::Handle;
use HTML::Entities;

print "Content-type: text/html\n\n";

print <<"";
<form method="post" action="/http-request.pl"
 enctype="multipart/form-data">
<input name="form_field" />
<input type="submit" name="Submit!" />
</form><hr />

print "<pre>";
my $request = HTTP::Request->parse( request_line() . "\n" .
                                    headers() . "\n\n" .
                                    request_body() );

print encode_entities($request->as_string());
print "</pre>";

sub request_line {
    return sprintf("%s %s %s",
                   $ENV{REQUEST_METHOD},
                   $ENV{REQUEST_URI},
                   $ENV{SERVER_PROTOCOL}
        );
}

sub headers {
    my @header_pair;
    for my $key ( grep /^HTTP_/, keys %ENV )
    {
        my $field = lc($key);
        $field =~ s/^http_//;
        $field =~ tr/_/-/;
        $field =~ s/\b(\w)/\U\1/g;
        push @header_pair, join(": ", $field, $ENV{$key});
    }
    return join "\n", @header_pair;
}

sub request_body {
    my $body = "";
    my $io = IO::Handle->new();
    if ($io->fdopen(fileno(STDIN),"r"))
    {
        while ( my $line = $io->getline )
        {
            $body .= $line;
        }
        $io->close;
    }
    return $body;
}