asp图片防盗链的一个简单方法--asp编程技术

<%
From_url = Cstr(Request.ServerVariables(HTTP_REFERER))
Serv_url = Cstr(Request.ServerVariables(SERVER_NAME))
'防止盗链，设置图片地址
if mid(From_url‚8‚len(Serv_url)) <> Serv_url then
response.redirect http://bbs.netton.cn/images/picerr.gif
response.end
end if
Function GetFileName(longname)'/folder1/folder2/file.asp=>file.asp
while instr(longname‚/)
longname = right(longname‚len(longname)-1)
wend
GetFileName = longname
End Function
Dim Stream
Dim Contents
Dim FileName
Dim TrueFileName
Dim FileExt
Const adTypeBinary = 1
FileName = Request.QueryString(FileName)
if FileName = Then
Response.End
End if
FileExt = Mid(FileName‚ InStrRev(FileName‚ .) + 1)
Response.Clear
if 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 if
Response.AddHeader content-disposition‚ attachment; filename= & GetFileName(Request.QueryString(FileName))
Set Stream = server.CreateObject(ADODB.Stream)
Stream.Type = adTypeBinary
Stream.Open
'设置服务器文件真实地址
TrueFileName = UpFile/&FileName
Stream.LoadFromFile Server.MapPath(TrueFileName)
While Not Stream.EOS
Response.BinaryWrite Stream.Read(1024 * 64)
Wend
Stream.Close
Set Stream = Nothing
Response.Flush
Response.End
%>