请问如何使用ASP.NET下载远程URL的文件到本地服务器？

[viphaiyang]

要下载的远程地址是：http://search.patentstar.com.cn/cprs2010/Docdb/GetBns.aspx?PNo=APP201180002436
问题是这个页面其实只是个跳转页，你下载试试看，就能看到真正的下载地址，下载的是一个PDF文件
在不知道真实地址的情况下，如何才能把这个文件下载到服务器？

[viphaiyang]

[ycproc]

这个页面做的是 加载操作 并不是下载

只有通过文件路径的 完整下载才是 下载

[孟子E章]

可以下载的啊

string Cookie = String.Empty;
String url = "http://search.patentstar.com.cn/cprs2010/Docdb/GetBns.aspx?PNo=APP201180002436";
String refer = url.Substring(0, url.LastIndexOf("/") + 1);
System.Net.HttpWebRequest req = System.Net.HttpWebRequest.Create(url) as System.Net.HttpWebRequest;
req.AllowAutoRedirect = false;
req.Referer = refer;
req.UserAgent = "Mozilla/5.0 (Windows; U; Windows NT 6.1; zh-CN; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13";
System.Net.HttpWebResponse res = req.GetResponse() as System.Net.HttpWebResponse;
System.Net.WebHeaderCollection headers = res.Headers;
String newUrl = "";
if ((res.StatusCode == System.Net.HttpStatusCode.Found) ||
  (res.StatusCode == System.Net.HttpStatusCode.Redirect) ||
  (res.StatusCode == System.Net.HttpStatusCode.Moved) ||
  (res.StatusCode == System.Net.HttpStatusCode.MovedPermanently))
{
  newUrl = headers["Location"];
  newUrl = newUrl.Trim();
}

if (headers["Set-Cookie"] != null)
{
  Cookie = headers["Set-Cookie"];
}

NameValueCollection collHeader = new NameValueCollection();
if (Cookie.Length > 0)
{
  collHeader.Add("Cookie", Cookie);
}
res.Close();
req = null;
    
String fileName = newUrl.Substring(newUrl.LastIndexOf("/") + 1);
req = System.Net.HttpWebRequest.Create(newUrl) as System.Net.HttpWebRequest;
req.AllowAutoRedirect = true;
req.Referer = url;
req.UserAgent = "Mozilla/5.0 (Windows; U; Windows NT 6.1; zh-CN; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13";
res = req.GetResponse() as System.Net.HttpWebResponse;
            
System.IO.Stream stream = res.GetResponseStream();
byte[] buffer = new byte[32 * 1024];
int bytesProcessed = 0;
System.IO.FileStream fs = System.IO.File.Create(Server.MapPath(fileName));
int bytesRead;
do
{
  bytesRead = stream.Read(buffer, 0, buffer.Length);
  fs.Write(buffer, 0, bytesRead);
  bytesProcessed += bytesRead;
}
while (bytesRead > 0);
fs.Flush();
fs.Close();
res.Close();
Response.Write("文件 " + fileName +  " 已经下载完成。");

参见
http://dotnet.aspx.cc/file/HttpWebRequest-Download-Redirected-File.aspx

[丁码农]

用HttpWebRequest HttpWebResponse就可以模拟http请求了
不过下载的东西，会保存在服务器端，而不是（浏览器）客户端哦。