Redirect non-members to homepage but allow access to PMPro checkout pages.

my-template-redirect-example.php

<?php
/**
 * Redirect non-members (including logged-in non-members) away from restricted pages and to login page.
 * This allows non-members to access Paid Memberships Pro checkout/levels pages as well as the default WordPress login page.
 *
 * Add this code to your PMPro Customizations Plugin - https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
 
 function my_redirect_non_members_example() {

	$okay_pages = array(pmpro_getOption('billing_page_id'), pmpro_getOption('account_page_id'), pmpro_getOption('levels_page_id'), pmpro_getOption('checkout_page_id'), pmpro_getOption('confirmation_page_id'));

	// Check if a non-member is trying to access any other page besides the above or home page.
	if ( ! is_front_page() && ! is_page( $okay_pages ) && ! pmpro_hasMembershipLevel() && ! strpos( $_SERVER['REQUEST_URI'], 'login' ) ) {
		wp_redirect( wp_login_url() );
		exit;
	}
}
add_action( 'template_redirect', 'my_redirect_non_members_example' );