https://blog.wongcw.com/2018/12/12/%e5%ae%9d%e5%a1%94%e9%9d%a2%e6%9d%bf%e5%bf%ab%e9%80%9f%e5%ae%89%e8%a3%85fileinfo%e7%bb%84%e4%bb%b6%e6%94%af%e6%8c%81%e6%96%b9%e6%b3%95/