admin-ajax.php Request Cache

ajax-cache.php

<?php
$cached_ajax_requests = array(
	'your-action-here',
);

$cached_ajax_expiration_time = 7 * DAY_IN_SECONDS;

if ( defined( 'DOING_AJAX' ) && DOING_AJAX && isset( $_REQUEST['action'] ) && in_array( $_REQUEST['action'], $cached_ajax_requests ) ) {
	$request_id = get_rocket_request_uniqid_171286();
	$data       = get_transient( 'rocket_get_ajax_cache_' . $request_id );

	if ( ! empty( $data ) ) {
		if ( rocket_is_json_171286( $data ) ) {
			$data = json_decode( $data );
			wp_send_json( $data );
		}

		echo $data;
		die();
	}

	ob_start();

	add_action( 'shutdown', function() {
		$request_id = get_rocket_request_uniqid_171286();
		set_transient( 'rocket_get_ajax_cache_' . $request_id, ob_get_clean(), $cached_ajax_expiration_time );
	}, 0 );
}

function get_rocket_request_uniqid_171286() {
	return hash( 'crc32', $_SERVER['REQUEST_URI'] . serialize( $_POST ) );
}

function rocket_is_json_171286( $string ) {
   return is_string( $string ) && is_array( json_decode( $string, true ) ) && ( json_last_error() == JSON_ERROR_NONE ) ? true : false;
}