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
/x-director", ".ebk": "application/x-expandedbook", ".emb": "chemical/x-embl-dl-nucleotide", ".embl": "chemical/x-embl-dl-nucleotide", ".eps": "application/postscript", ".epub": "application/epub+zip", ".eri": "image/x-eri", ".es": "audio/echospeech", ".esl": "audio/echospee