# at the top of the script

use Data::Dumper;

... # later

print Dumper $input;

# or, sometimes more effective to ensure
# that each var doesn't have newlines or other
# nonsense

for (qw(to from body)){
    print "\n\n>$input->{$_}<\n\n";
}

unless (($input->{to}) && ($input->{from}) && ($input->{body}) && ($in
+put->{id})) {

##</code><code>##

>steveb@cpan.org<

##</code><code>##

open my $wfh, '>', '/home/user/debug.txt' or die $!;

for (qw(to from body)){
    print $wfh "\n\n>$input->{$_}<\n\n";
}