Unique file name caching system for beaverbeaver. This is perfect if you use a CDN or strip out url parameters. This class clones the layout files and generates assets.

class-box-builder-cache.php

<?php

// Exit if accessed directly
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

if ( class_exists( 'FLBuilder' ) ) {
	/**
	 * Caching Solutions for _box-Builder
	 *
	 * @since         1.1.0
	 * @package       _box_Builder_Modules
	 * @subpackage    _box_Builder_Modules/caching
	 * @author        Image in a Box <[email protected]>
	 */
	class _box_Builder_Cache {

		/** @var string Meta_Key used for this class */
		private $meta_key = '_box_builder_unique_cache_id';

		/**
		 * The single instance of this class
		 *
		 * @since 1.0.0
		 *
		 * @var _box_Builder_Cache|null
		 */
		protected static $instance = null;

		/**
		 * _box_Builder_Cache constructor.
		 */
		public function __construct() {

			$this->loader();
		}

		/**
		 * Loader functions for all the hooks/filters
		 */
		public function loader() {

			add_action( 'fl_builder_after_save_layout', [ $this, 'generate_unique_assets' ], 999, 2 );
			add_action( 'fl_builder_after_render_js', [ $this, 'clone_asset_js' ] );
			add_action( 'fl_builder_after_render_css', [ $this, 'clone_asset_css' ] );

			add_action( 'wp_enqueue_scripts', [ $this, 'change_paths_as_needed' ], 999 );
		}

		/**
		 * Updates the timestamp for the specific post.
		 *
		 * @param integer $post_id
		 * @param boolean $publish
		 */
		public function generate_unique_assets( $post_id, $publish ) {

			if ( $publish && $post_id ) {

				$last_unique_time = get_post_meta( $post_id, $this->meta_key, true );

				if ( ! empty( $last_unique_time ) ) {
					$this->remove_old_cached( $post_id, $last_unique_time );
				}
				update_post_meta( $post_id, $this->meta_key, time() );
			}
		}

		/**
		 * Change the enqueued paths to the new cached versions.
		 */
		public function change_paths_as_needed() {

			$post_id = FLBuilderModel::get_post_id();

			if ( ! empty( $post_id ) ) {

				$wp_styles  = wp_styles();
				$wp_scripts = wp_scripts();

				if ( ! is_admin() ) {

					$last_unique_time = get_post_meta( $post_id, $this->meta_key, true );

					if ( ! empty( $last_unique_time ) ) {
						$handler   = 'fl-builder-layout-' . $post_id;
						$filepaths = $this->get_asset_names( $post_id, $last_unique_time );

						if ( isset( $wp_styles->registered[$handler] ) && file_exists( $filepaths['css'] ) ) {
							$wp_styles->registered[$handler]->src = $filepaths['css_url'];
						}
						if ( isset( $wp_scripts->registered[$handler] ) && file_exists( $filepaths['js'] ) ) {
							$wp_scripts->registered[$handler]->src = $filepaths['js_url'];
						}
					}
				}
			}
		}

		/**
		 * Delete the old cached items
		 *
		 * @param        $post_id
		 * @param string $time
		 */
		public function remove_old_cached( $post_id, $time = '' ) {

			if ( empty( $time ) ) {
				return;
			}

			$files = $this->get_asset_names( $post_id, $time );

			$paths = array(
				$files['css'],
				$files['js']
			);

			foreach ( $paths as $path ) {
				if ( file_exists( $path ) ) {
					unlink( $path );
				}
			}
		}

		/**
		 * Clone on JS change
		 */
		public function clone_asset_js() {
			$this->clone_asset( 'js' );
		}

		/**
		 * Clone on CSS change
		 */
		public function clone_asset_css() {
			$this->clone_asset( 'css' );
		}

		/**
		 * Clone the asssets AFTER the builder has generated the new assets.
		 *
		 * @param string $type
		 */
		private function clone_asset( $type = '' ) {

			try {
				$post_id = FLBuilderModel::get_post_id();
				if ( empty( $post_id ) ) {
					return;
				}

				$last_unique_time = get_post_meta( $post_id, $this->meta_key, true );

				if ( ! empty( $last_unique_time ) ) {
					$filePaths = $this->get_asset_names( $post_id, $last_unique_time );

					if( $type == 'css' ) {
						$filename     = $filePaths['original_css'];
						$copyFilename = $filePaths['css'];
					} else {
						$filename     = $filePaths['original_js'];
						$copyFilename = $filePaths['js'];
					}

					if ( file_exists( $filename ) ) {
						if ( ! copy( $filename, $copyFilename ) ) {
							throw new Exception( 'Could not copy filename from: ' . $filename . ' --- ' . $copyFilename );
						}
					}
				}
			}
			catch ( Exception $e ) {
				error_log( $e );

				return;
			}
		}

		/**
		 * Gets the custom names.
		 *
		 * @param int    $post_id
		 * @param string $time
		 *
		 * @return array
		 */
		public function get_asset_names( $post_id = 0, $time = '' ) {

			$cache_dir = FLBuilderModel::get_cache_dir();

			return [
				'original_css' => $cache_dir['path'] . $post_id . '-layout.css',
				'css'          => $cache_dir['path'] . $post_id . '-layout-' . $time . '.css',
				'css_url'      => $cache_dir['url'] . $post_id . '-layout-' . $time . '.css',
				'original_js'  => $cache_dir['path'] . $post_id . '-layout.js',
				'js'           => $cache_dir['path'] . $post_id . '-layout-' . $time . '.js',
				'js_url'       => $cache_dir['url'] . $post_id . '-layout-' . $time . '.js',
			];
		}

		/**
		 * Main _box_Builder_Cache instance
		 *
		 * Ensures only one instance of _box_Builder_Cache is loaded or can be loaded
		 *
		 * @since 1.0.0
		 *
		 * @return _box_Builder_Cache|null
		 */
		public static function instance() {
			if ( is_null( self::$instance ) ) {
				self::$instance = new self();
			}

			return self::$instance;
		}
	}

	/**
	 * Global Function if needed
	 *
	 * @return _box_Builder_Cache|null
	 */
	function _box_builder_cache() {

		return _box_Builder_Cache::instance();
	}

	add_action( 'init', '_box_builder_cache' );

}