PMPro - Allow Access to Certain Series Non-Members

pmpro-allow-preview-access.php

<?php
/**
 * Allow non-logged-in users access to certain series.
 * 
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
/**
 * Allow access to certain series for non-logged-in-members.
 */
function my_pmpros_pmpro_has_membership_access_filter( $hasaccess, $post, $user, $post_membership_levels ) {
	if ( is_user_logged_in() ) {
		return $hasaccess;
	}
	$series_ids_to_allow = array(
		875,
		18662,
	);
	$post_id             = get_queried_object_id();

	if ( get_post_type( $post_id ) == 'pmpro_series' ) {
		return true;
	}


	$maybe_in_series     = get_post_meta( $post_id, '_post_series', true );
	if ( ! $maybe_in_series || ! is_array( $maybe_in_series ) || empty( $maybe_in_series ) ) {
		return $hasaccess;
	}

	foreach ( $series_ids_to_allow as $series_id ) {
		if ( in_array( $series_id, $maybe_in_series ) ) {
			return true;
		}
	}
	return $hasaccess;
}
add_filter( 'pmpro_has_membership_access_filter', 'my_pmpros_pmpro_has_membership_access_filter', 15, 4 );