noindex_ppp.php

<?php
namespace PWCC\NoIndexPPP;

if ( ! is_admin() ) {
	add_action( 'pre_get_posts', __NAMESPACE__ . '\\show_public_preview' );
}

/**
 * Filter the Yoast SEO and AIOSEO robots meta tag for public previews.
 *
 * Helper for Public Post Preview plugin.
 *
 * Detects if a page is a public preview using the same logic as the PPP plugin
 * and filters the AIOSEO & Yoast SEO robots meta tag to noindex if it is.
 *
 * This runs on the `pre_get_posts` action but makes no changes to the query.
 *
 * @param WP_Query $query The WP_Query instance.
 */
function show_public_preview( $query ) {
	if (
		class_exists( 'DS_Public_Post_Preview' ) &&
		$query->is_main_query() &&
		$query->is_preview() &&
		$query->is_singular() &&
		$query->get( '_ppp' )
	) {
		add_filter( 'wpseo_robots', __NAMESPACE__ . '\\return_noindex' );
		add_filter( 'aioseo_robots_meta', __NAMESPACE__ . '\\aioseo_noindex' );
	}
}

/**
 * Set the AIOSEO robots meta tag attributes to noindex.
 *
 * @return array Modified AIOSEO meta tag attributes.
 */
function aioseo_noindex( $attributes ) {
	$attributes['noindex'] = 'noindex';
	return $attributes;
}

/**
 * Return the string 'noindex'.
 *
 * @return string The string 'noindex'.
 */
function return_noindex() {
	return 'noindex';
}