下载前检查下载大小

Question

我需要一些方法来检查下载的大小,而无需下载整个文件.我正在使用C#和System.Net.WebClient进行下载.检查需要在asp.net webservice中运行.

谢谢

Answer 1

使用HTTP方法HEAD检索Content-Length:标头.

HEAD / HTTP/1.1
Host: www.example.com

HTTP/1.1 200 OK
Date: Wed, 18 Mar 2009 11:21:51 GMT
Server: Apache/2.2.3 (CentOS)
Last-Modified: Tue, 15 Nov 2005 13:24:10 GMT
ETag: "b80f4-1b6-80bfd280"
Accept-Ranges: bytes
Content-Length: 438 
Connection: close
Content-Type: text/html; charset=UTF-8