如果我们知道一个静态文件的实际路径如：http://www.xx.com/download/51windows.pdf，如果服务器没有作特别的限制设置，我们就可以毫不费力的把它下载下来！当网站提供51windows.pdf下载时，怎么样才能让下载者无法得到他的实际路径呢！本文就来介绍如何使用Asp来隐藏文件的实际下载路径。
我们在管理网站文件时，可以把扩展名一样的文件放在同一个目录下，起一个比较特别名字，例如放pdf文件目录为the_pdf_file_s，把下面代码另存为down.asp，他的网上路径为http://www.xx.com/down.asp，我们就可以用http://www.xx.com/down.asp?FileName=51windows.pdf来下载这个文件了，而且下载者无法看到这个文件实际下载路径的！在down.asp中我们还可以设置下载文件是否需要登陆，判断下载的来源页是否为外部网站，从而可以做到防止文件被盗链。
示例代码：
<%From_url = Cstr(Request.ServerVariables('HTTP_REFERER'))Serv_url = Cstr(Request.ServerVariables('SERVER_NAME'))if mid(From_url,8,len(Serv_url)) <> Serv_url then response.write '非法链接！' '防止盗链 response.endend ifif Request.Cookies('Logined')='' then response.redirect '/login.asp' '需要登陆！end ifFunction GetFileName(longname)'/folder1/folder2/file.asp=>file.asp while instr(longname,'/') longname = right(longname,len(longname)-1) wend GetFileName = longnameEnd FunctionDim StreamDim ContentsDim FileNameDim TrueFileNameDim FileExtConst adTypeBinary = 1FileName = Request.QueryString('FileName')if FileName = '' Then Response.Write '无效文件名！' Response.EndEnd ifFileExt = Mid(FileName, InStrRev(FileName, '.') + 1)Select Case UCase(FileExt) Case 'ASP', 'ASA', 'ASPX', 'ASAX', 'MDB'Response.Write '非法操作！'Response.EndEnd SelectResponse.Clearif lcase(right(FileName,3))='gif' or lcase(right(FileName,3))='jpg' or lcase(right(FileName,3))='png' then Response.ContentType = 'image/*' '对图像文件不出现下载对话框else Response.ContentType = 'application/ms-download'end ifResponse.AddHeader 'content-disposition', 'attachment; filename=' & GetFileName(Request.QueryString('FileName'))Set Stream = server.CreateObject('ADODB.Stream')Stream.Type = adTypeBinaryStream.Openif lcase(right(FileName,3))='pdf' then '设置pdf类型文件目录 TrueFileName = '/the_pdf_file_s/'&FileNameend if if lcase(right(FileName,3))='doc' then '设置DOC类型文件目录 TrueFileName = '/my_D_O_C_file/'&FileNameend ifif lcase(right(FileName,3))='gif' or lcase(right(FileName,3))='jpg' or lcase(right(FileName,3))='png' then TrueFileName = '/all_images_/'&FileName '设置图像文件目录end ifStream.LoadFromFile Server.MapPath(TrueFileName)While Not Stream.EOS Response.BinaryWrite Stream.Read(1024 * 64)WendStream.CloseSet Stream = NothingResponse.FlushResponse.End%>
