Edit file File name : CacheNameSpaceTrait.php Content :<?php namespace Automattic\WooCommerce\Caching; /** * Implements namespacing algorithm to simulate grouping and namespacing for wp_cache, memcache and other caching engines that don't support grouping natively. * * See the algorithm details here: https://github.com/memcached/memcached/wiki/ProgrammingTricks#namespacing. * * To use the namespacing algorithm in the CacheEngine class: * 1. Use a group string to identify all objects of a type. * 2. Before setting cache, prefix the cache key by using the `get_cache_prefix`. * 3. Use `invalidate_cache_group` function to invalidate all caches in entire group at once. */ trait CacheNameSpaceTrait { /** * Get prefix for use with wp_cache_set. Allows all cache in a group to be invalidated at once. * * @param string $group Group of cache to get. * @return string Prefix. */ public static function get_cache_prefix( $group ) { // Get cache key - uses cache key wc_orders_cache_prefix to invalidate when needed. $prefix = wp_cache_get( 'wc_' . $group . '_cache_prefix', $group ); if ( false === $prefix ) { $prefix = microtime(); wp_cache_set( 'wc_' . $group . '_cache_prefix', $prefix, $group ); } return 'wc_cache_' . $prefix . '_'; } /** * Increment group cache prefix (invalidates cache). * * @param string $group Group of cache to clear. */ public static function incr_cache_prefix( $group ) { wc_deprecated_function( 'WC_Cache_Helper::incr_cache_prefix', '3.9.0', 'WC_Cache_Helper::invalidate_cache_group' ); self::invalidate_cache_group( $group ); } /** * Invalidate cache group. * * @param string $group Group of cache to clear. * @since 3.9.0 */ public static function invalidate_cache_group( $group ) { return wp_cache_set( 'wc_' . $group . '_cache_prefix', microtime(), $group ); } /** * Helper method to get prefixed key. * * @param string $key Key to prefix. * @param string $group Group of cache to get. * * @return string Prefixed key. */ public static function get_prefixed_key( $key, $group ) { return self::get_cache_prefix( $group ) . $key; } } Save