public function downAction() {        $data = http://www.mamicode.com/fn_authcode(base64_decode($this->get(‘file‘)), ‘DECODE‘);"Location: $file");        } else {            //本地            $file = str_replace(‘..‘, ‘‘, $file);//将变量file里的..替换为空            $file = strpos($file, ‘/‘) === 0 ? APP_ROOT.$file : $file;//找$file出现在第一位，则返回根路径+$file            if (!is_file($file)) {                $this->msg(lang(‘a-mod-214‘) . ‘(#‘ . $file . ‘)‘);            };            header(‘Pragma: public‘);            header(‘Last-Modified: ‘ . gmdate(‘D, d M Y H:i:s‘) . ‘ GMT‘);            header(‘Cache-Control: no-store, no-cache, must-revalidate‘);            header(‘Cache-Control: pre-check=0, post-check=0, max-age=0‘);            header(‘Content-Transfer-Encoding: binary‘);            header(‘Content-Encoding: none‘);            header(‘Content-type: ‘ . strtolower(trim(substr(strrchr($file, ‘.‘), 1, 10))));//strchr是从首个出现.的地方开始截断。strolower转换为小写。            header(‘Content-Disposition: attachment; filename="‘ . basename($file) . ‘"‘);            header(‘Content-length: ‘ . sprintf("%u", filesize($file)));//springtf：把%号替换成一个作为参数，进行传递的变量。            readfile($file);            exit;        }    }