S2Member API – Signup Notifications

/* USING S2 NOTIFICATIONS API
 * ADD SUBSCRIPTION DETAILS FOR USERS WITH 100% DISCOUNTS 
 * using Signup Notification URL https://wmhca.org/?s2_signup_notification=yes&user_email=%%payer_email%%&coupon=%%coupon_code%%
 */
add_action( 'init', 's2_signup_notification' ) ;

function s2_signup_notification() {
  
    if ( ! empty( $_GET['s2_signup_notification'] ) && $_GET['s2_signup_notification'] === 'yes' ) {
    
        if( ! empty( $_GET['user_email'] ) && ! empty( $_GET['coupon'] ) ) {
      
      $user_id 		= get_user_by( 'email',$_GET['user_email'] )->ID ; 
      
      //use current time as start time
      $period_start 	= date( 'Y/m/d', time() ) ;
      
      //create 1-year subscription term as default (YMMV)
      $year_from_now 	= time() + 31536000 ;
      $period_end 	= date( 'Y/m/d', $year_from_now ) ;
      
      //add coupon name as string (is typically saved by S2 as serialized, not necessary or helpful in many cases
      update_user_meta( $user_id, 'wp_s2member_coupon_codes', $_GET['coupon'] ) ; 
      
      //create 1-year subscription term as default (YMMV)
      update_user_meta( $user_id, 'wp_s2member_auto_eot_time', $year_from_now ) ;
      update_user_meta( $user_id, 'current_subscription_start_date', $period_start ) ;
      update_user_meta( $user_id, 'current_subscription_end_date', $period_end ) ;
      
        }
    
        exit ; // We can exit here. There's no reason to continue loading WordPress in this case.
    
    }
  
}