W3TC generate minified filename by checksum

snippet.php

<?php
// Based on https://wordpress.org/support/topic/how-to-change-minified-css-file-name/
//    Get all the files, read them, concat them, get a md5 hash, cut at 10 and generate a new filename
// Why?
// W3TC generate the hashname based on the filenames so not invalidate the cache if there are changes

add_filter('w3tc_minify_urls_for_minification_to_minify_filename', 'w3tc_filename_filter', 20, 3);
function w3tc_filename_filter($minify_filename, $files, $type ){
	$path_parts = pathinfo( $minify_filename );
    $content = '';
	foreach ( $files as &$asset ) {
		$content .= file_get_contents( ABSPATH . '/' . $asset );
	}

    return substr( md5( $content ), 10 ) . '.' . $path_parts[ 'extension' ];
}