加载最新资源（css,js） 封装的方法

function newf($filename) {
    $filestr = file_get_contents(public_path('file_version.json'));
    if (empty($filestr)) {
        $filearr = array();
        $filearr[$filename]['key'] = md5_file(public_path($filename));
        $filearr[$filename]['src'] = $filename . "?" . time();
    } else {
        $filearr = unserialize($filestr);
        if (in_array($filename, array_keys($filearr))) {
            if ($filearr[$filename]['key'] != md5_file(public_path($filename))) {
                $filearr[$filename]['key'] = md5_file(public_path($filename));
                $filearr[$filename]['src'] = $filename . "?" . time();
            }
        } else {
            $filearr[$filename]['key'] = md5_file(public_path($filename));
            $filearr[$filename]['src'] = $filename . "?" . time();
        }
    }
    file_put_contents(public_path('file_version.json'), serialize($filearr));
    return $filearr[$filename]['src'];
}