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: https://dominikschilling.de/
 * Plugin URI: https://gist.github.com/ocean90/1966227/
 *
 * 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' );

Does anyone know why this would be working perfectly for me locally (Apache/PHP 7) but on the remote test server (Nginx/PHP 5.6) it's failing with errors regarding https. Both my local server and remote test site have SSL enabled, but on the remote server, I'm getting 'blocked - mixed content' errors. It seems to be trying to load everything over http, even though I changed the plugin's code (line 42) to "https:".

Is there something to do with PHP 7 vs PHP 5.6 here, or apache vs nginx, or is it something else?

Seems to be an issue with Nginx, as cdshepherd noted. Bummer, I thought this was going to solve my cache problems.

I got it working on nginx, but had to change it to filename modified date instead of the version string.

  location ~* ^(.+)\.(?:\d+)\.(min.js|min.css|js|css)($|\?.*$) {
   try_files $uri $1.$2;
 }`

The advantage is that with this rule the server first checks whether the requested filename exists and only if it doesn't tries to serve the file without the version number.

The solution is heavily based on these two:
https://wordpress.org/plugins/filename-based-asset-cache-busting/
https://github.com/h5bp/server-configs-nginx/blob/master/h5bp/location/cache-busting.conf

<?php
/**
 * Plugin Name: Brower Cache Buster
 * 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 (Untested):
 *
 *   <IfModule mod_rewrite.c>
 *     RewriteEngine On
 *     RewriteBase /
 *
 *     RewriteCond %{REQUEST_FILENAME} !-f
 *     RewriteCond %{REQUEST_FILENAME} !-d
 *     RewriteRule ^(.+)\.(?:\d+)\.(min.js|min.css|js|css)($|\?.*$) $1.$3 [L]
 *   </IfModule>
 *
 *
 * Extend your nginx config with these lines (tested & working):
 *
 * location ~* ^(.+)\.(?:\d+)\.(min.js|min.css|js|css)($|\?.*$) {
 *   try_files $uri $1.$2;
 * }
 */

/**
 * Removes query strings of the source.
 * Adds the file modified time to the filename.
 * Doesn't change admin scripts/styles and sources.
 *
 * @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;
	}

	$file_path = ABSPATH . $_src['path'];
	if (file_exists($file_path)) {
		return preg_replace(
			'/\.(min.js|min.css|js|css)($|\?.*$)/',
			'.' . filemtime($file_path) . '.$1',
			$src
		);
	} else {

		return $src;
	}
}
add_filter( 'script_loader_src', 'ds_filename_based_cache_busting' );
add_filter( 'style_loader_src', 'ds_filename_based_cache_busting' );

Is this plugin similar in functionality/purpose to the Busted plugin?

Is it possible to applies the feature to images?

This gist was the start point for this plugin: https://wordpress.org/plugins/filename-based-asset-cache-busting/

It's been improved/has a few new features + conveniences compared to the gist; eg: it modifies .htaccess for you, sets caching headers properly and includes a querystring mode if you can't get .htaccess to work on your hosting.

(Disclaimer: I adapted the gist to create the plugin)