当客户端想要下载文件时,nodejs服务端如何根据URL设置响应头的Content-Type类型
": "image/x-rgb", ".rlf": "application/x-richlink", ".rm": "audio/x-pn-realaudio", ".rmf": "audio/x-rmf", ".rmi": "audio/mid", ".rmm": "audio/x-pn-realaudio", ".rmvb": "audio/x-pn-realaudio", ".rnx": "application/vnd.rn-realplayer", ".roff": "application/x-troff", ".rp":