Filename-based cache busting for WordPress scripts/styles.

fbcbfwss.php

<?php
/**
 * Filename-based cache busting for WordPress scripts/styles.
 *
 * 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>
 *
 * @param  string $src The source with ?ver= suffix
 * @return string
 */
function ds_filename_based_cache_busting( $src ) {
	// Don't touch admin scripts.
	if ( is_admin() )
		return $src;

	// Get the version string.
	preg_match( '/\?ver=(.+)/', $src, $match );
	$version = $match[1];

	// No version detected, return the source.
	if ( empty ( $version ) )
		return $src;

	// Remove version string from the source.
	$src = preg_replace( '/\?ver=(.+)/', '', $src );

	// Get the extension of the file, can be '.js' or '.css'.
	$ext = '.' . pathinfo( $src, PATHINFO_EXTENSION );

	// Build the new source.
	$src = str_replace( $ext, '.' . $version . $ext, $src );

	// Return the new source.
	return $src;
}

add_filter( 'script_loader_src', 'ds_filename_based_cache_busting' );
add_filter( 'style_loader_src', 'ds_filename_based_cache_busting' );