Register only via a specific e-mail domain

Question

I need to allow users to register for a Drupal-6 site, but only if their email contains a specific domain. For example, only allow users with whatever.com in their email address to register; a user with the email bob@whatever.com can register for the site, but bob@something.com cannot register for the site.

Is there a module for this? If not, which file would the PHP need to be altered for this?

Answer 1

the "user restrictions module" is supposed to offer that feature. But it doesn't seem ready for production yet. However you could use the code to write your own.

I also tried to do it with the rules module and setup a rule for the "event" "user: before saving account" with a condition "data comparison" on field "account:mail". Add "value contains" and use "@whatever.com" and then check the "negate" box. That will basically trigger the rule for all emails that don't contain @whatever.com.

However I couldn't find a way to stop the username from getting saved. If you use the event "user: after saving account" you can show an error to the user and block the account. It prevents the registration but shows a second message to your user "you'll get notified by the administrator". Not a great experience for your customers.

Answer 2

I just wrote a hook to do something similar:

function MYMODULE_form_user_register_form_alter(&$form, $form_state, $form_id) {
  if (!($form_id == 'user_register_form')) {
    return;
  }

//if form is submitted validate the input
if ($form_state['method'] == 'post' && isset($form_state['input']['name']) ){

  $username = $form_state['input']['name'];
  if (strlen($username) < 5 || strlen($username) > 20) {
    $error_msg = t('The username has to be between 5 and 20 characters long. ');
    form_set_error('name', $error_msg);