check_dns.module in Check DNS 7

Prevents user registration with invalid email domain.

File

check_dns.module

<?php

/**
 * @file
 * Prevents user registration with invalid email domain.
 */

/**
 * Implements hook_help().
 */
function check_dns_help($path, $arg) {
  switch ($path) {
    case 'admin/help#check_dns':
      $output = '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('The Check DNS module simply prevents user registration with invalid email domain on user registration form.') . '</p>';
      $output .= '<p>' . t('It validates email domain before registration and checks if the domain exists. This prevents false registration.') . '</p>';
      return $output;
  }
}

/**
 * Implements hook_form_form_id_form_alter().
 */
function check_dns_form_user_register_form_alter(&$form, &$form_state, $form_id) {
  $form['#validate'][] = 'check_dns_user_register_validate';
}

/**
 * Custom validation function for user_register_form().
 *
 * Checks if the domain in the email address is on a list of allowed domains.
 */
function check_dns_user_register_validate(&$form, &$form_state) {

  // Ignore validation if mail already has an error.
  $errors = form_get_errors();
  if (!empty($errors['mail'])) {
    return;
  }

  // Get the email.
  $mail = explode('@', $form_state['values']['mail']);

  // Fetch DNS Resource Records associated with a hostname.
  $result = dns_check_record(end($mail));
  if (!$result) {

    // If no record is found.
    $error_message = t('Your email domain is not recognised. Please enter a valid email id.');
    form_set_error('account', $error_message);
  }
  else {
    return;
  }
}

Functions

Name	Description
check_dns_form_user_register_form_alter	Implements hook_form_form_id_form_alter().
check_dns_help	Implements hook_help().
check_dns_user_register_validate	Custom validation function for user_register_form().