WordPress Plugin: Filename-based cache busting for scripts/styles.

fbcbfwss.php

<?php
/**
 * Plugin Name: Filename-based cache busting
 * Version: 0.3
 * Description: Filename-based cache busting for WordPress scripts/styles.
 * Author: Dominik Schilling
 * Author URI: http://wphelper.de/
 * Plugin URI: https://dominikschilling.de/880/
 *
 * License: GPLv2 or later
 * License URI: http://www.gnu.org/licenses/gpl-2.0.html
 *
 *
 * Extend your .htaccess file with these lines:
 *
 *   <IfModule mod_rewrite.c>
 *     RewriteEngine On
 *     RewriteBase /
 *
 *     RewriteCond %{REQUEST_FILENAME} !-f
 *     RewriteCond %{REQUEST_FILENAME} !-d
 *     RewriteRule ^(.+)\.(.+)\.(js|css)$ $1.$3 [L]
 *   </IfModule>
 */

/**
 * Moves the `ver` query string of the source into
 * the filename. Doesn't change admin scripts/styles and sources
 * with more than the `ver` arg.
 *
 * @param  string $src The original source.
 * @return string
 */
function ds_filename_based_cache_busting( $src ) {
	// Don't touch admin scripts.
	if ( is_admin() ) {
		return $src;
	}

	$_src = $src;
	if ( '//' === substr( $_src, 0, 2 ) ) {
		$_src = 'http:' . $_src;
	}

	$_src = parse_url( $_src );

	// Give up if malformed URL.
	if ( false === $_src ) {
		return $src;
	}

	// Check if it's a local URL.
	$wp = parse_url( home_url() );
	if ( isset( $_src['host'] ) && $_src['host'] !== $wp['host'] ) {
		return $src;
	}

	return preg_replace(
		'/\.(js|css)\?ver=(.+)$/',
		'.$2.$1',
		$src
	);
}
add_filter( 'script_loader_src', 'ds_filename_based_cache_busting' );
add_filter( 'style_loader_src', 'ds_filename_based_cache_busting' );