CGI script for collecting username and password and storing them in a database table (See related posts)

#!/usr/bin/perl

# $Id$

# CGI script for collecting username and password and storing them in a database
# table. The password is encrypted with Crypt::PasswdMD5 ready for passing to
# useradd.

use strict;
use warnings;

## no critic (ValuesAndExpressions::RequireInterpolationOfMetachars)
our ($VERSION) = '$Revision$' =~ m{ \$Revision: \s+ (\S+) }xms;
## use critic

use CGI::Pretty qw(:standard -nosticky);
use DBI;
use Crypt::PasswdMD5;

# Schema for database table to store account details:
# 
# CREATE TABLE account (
#     username varchar(50) NOT NULL,
#     password varchar(50) NOT NULL,
#     date_created datetime NOT NULL
# );

my $DBNAME = 'database';
my $DBHOST = 'localhost';
my $DBPORT = 3306;
my $DBUSER = 'username';
my $DBPASS = 'password';

# Header
my $q = new CGI;
print $q->header(),
      $q->start_html(
          -title => 'New Account',
          -lang  => 'en',
      ),
      $q->h1('New Account');

my $submit    = $q->param('submit')    || q{};
my $username  = $q->param('username')  || q{};
my $password1 = $q->param('password1') || q{};
my $password2 = $q->param('password2') || q{};

my %ERROR = (
    no_username         => 'You must specify a username.',
    no_password         => 'You must specify a password.',
    password_not_twice  => 'You must specify your password twice.',
    passwords_not_match => 'Both passwords must match.',
);

my $error = (!$submit)                   ? undef                       :
            (!$username)                 ? $ERROR{no_username}         :
            (!$password1 && !$password2) ? $ERROR{no_password}         :
            (!$password1 || !$password2) ? $ERROR{password_not_twice}  :
            ( $password1 ne  $password2) ? $ERROR{passwords_not_match} :
                                           undef
            ;

if (!$submit) {
    # Form not submitted, so display empty form
    form($q);
}
elsif ($error) {
    # Show error and redisplay form
    print $q->p($error);
    form($q, $username);
}
else {
    # Enter account details into database
    my $dsn = "DBI:mysql:database=$DBNAME;host=$DBHOST;port=$DBPORT";
    my $dbh = DBI->connect($dsn, $DBUSER, $DBPASS);
    
    my $username_quoted = $dbh->quote(param('username'));
    my $password_quoted = $dbh->quote(unix_md5_crypt(param('password1')));
    
    $dbh->do("
        INSERT INTO account
        (username, password, date_created)
        VALUES ($username_quoted, $password_quoted, NOW())
    ");
    
    print $q->p('Your username and password have been recorded.');
}

# Footer
print $q->end_html();

sub form {
    my $q = shift;
    my $username = shift || q{};
    
    print start_form(),
          p('Username:', br(), textfield(
              -name  => 'username',
              -value => $username,
          )),
          p('Password:', br(), password_field(
              -name => 'password1',
          )),
          p('Password (again):', br(), password_field(
              -name => 'password2',
          )),
          p(submit(
              -name  => 'submit',
              -value => 'Submit',
          )),
          end_form();
    
    return;
}