[WordPress][WP Rocket] Check if a visitor is WP Rocket’s preload user agent.

wp-rocket-is-preload.php

<?php
/**
 * More about WP Rocket’s preload options in this document:
 * @link http://docs.wp-rocket.me/article/8-how-the-cache-is-preloaded
 */

/**
 * Check if a visitor is WP Rocket’s preload user agent (bot or sitemap).
 * This will trigger only on a document that has not been cached yet.
 * 
 * @return boolean True: visitor is preload UA, else false
 */
function wp_rocket__is_preload() {

	return 'wprocketbot' === $_SERVER ['HTTP_USER_AGENT'] ? true : false;
}

/**
 * Show to preload bot only.
 */
if ( wp_rocket__is_preload() ) {
	
	// Displayed only for preload bot.
	
}

/**
 * Hide from preload bot.
 */
if ( ! wp_rocket__is_preload() ) {
	
	// Hidden from preload bot.
	
}