Restricting Registration for a member level

#1

Is there a way to restrict who can subscribe to a member level?

Example would be only allowing users with a .edu email address to subscribe to a certain level.

#2

I haven’t tried restricting the application of an email whitelist to a specific user level, so you’ll have to modify this code for your purposes. Subject to that caveat, this code works with any s2Member Pro form (including free Pro forms):

function kts_restrict_domains( $response, $form, $s ) {
    $whitelist = array(
	'someplace.edu',
        'someotherplace.edu',
    );
    if ( !$response ) // No other errors produced by s2Member itself?
        if ( $form === 'registration' || !is_user_logged_in() ) // Any new registration, or any new user completing checkout.
        {
            $domain = ''; // Initialize.
            if( isset( $s['email']) && strpos( ( string)$s['email'], '@' ) !== FALSE )
                list(, $domain) = explode('@', ( string )$s['email'], 2 );

            if ( !$domain || !in_array( strtolower( $domain ), array_map( 'strtolower', $whitelist ), TRUE ) )
                $response = array(
                    'error'    => TRUE, // This is an error.
                    'response' => _x( 'ERROR: You must register using the email address associated with your institution.', 's2member-front', 's2member' ),
                );
        }
    return $response; // Always return the filtered response.
}
add_filter( 'ws_plugin__s2member_pro_paypal_form_submission_validation_response', 'kts_restrict_domains', 10, 3 );
add_filter( 'ws_plugin__s2member_pro_stripe_form_submission_validation_response', 'kts_restrict_domains', 10, 3 );