用Asp隐藏文件路径,实现防盗链
<P>如果我们知道一个静态文件的实际路径如：<FONT color=#0000ff>http://www.xx.com/download/51windows.pdf</FONT>，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。</P><P>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<FONT color=#0000ff>http://www.xx.com/down.asp</FONT>，我们就可以用<FONT color=#0000ff>http://www.xx.com/down.asp?FileName=51windows.pdf</FONT>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。 </P>
<P>[quote] </P>
<P>示例代码：<BR><%<BR>From_url = Cstr(Request.ServerVariables("HTTP_REFERER"))<BR>Serv_url = Cstr(Request.ServerVariables("SERVER_NAME"))<BR>if mid(From_url,8,len(Serv_url)) <> Serv_url then<BR>response.write "非法链接！" '防止盗链<BR>response.end<BR>end if<BR>if Request.Cookies("Logined")="" then<BR>response.redirect "/login.asp" '需要登陆！<BR>end if<BR>Function GetFileName(longname)'/folder1/folder2/file.asp=>file.asp<BR>while instr(longname,"/")<BR>longname = right(longname,len(longname)-1)<BR>wend<BR>GetFileName = longname<BR>End Function</P>
<P>Dim Stream<BR>Dim Contents<BR>Dim FileName<BR>Dim TrueFileName<BR>Dim FileExt<BR>Const adTypeBinary = 1<BR>FileName = Request.QueryString("FileName")<BR>if FileName = "" Then<BR>Response.Write "无效/webpage/asp/041101/24.htm！"<BR>Response.End<BR>End if</P>
<P>FileExt = Mid(FileName, InStrRev(FileName, ".") + 1)<BR>Select Case UCase(FileExt)<BR>Case "ASP", "ASA", "ASPX", "ASAX", "MDB"<BR>Response.Write "非法操作！"<BR>Response.End<BR>End Select</P>
<P>Response.Clear</P>
<P>if lcase(right(FileName,3))="gif" or lcase(right(FileName,3))="jpg" or lcase(right(FileName,3))="png" then<BR>Response.ContentType = "image/*" '对图像文件不出现下载对话框<BR>else<BR>Response.ContentType = "application/ms-download"<BR>end if</P>
<P>Response.AddHeader "content-disposition", "attachment; 200497141230.htm=" & GetFileName(Request.QueryString("FileName"))<BR>Set Stream = server.CreateObject("ADODB.Stream")<BR>Stream.Type = adTypeBinary<BR>Stream.Open<BR>if lcase(right(FileName,3))="pdf" then '设置pdf类型文件目录<BR>TrueFileName = "/the_pdf_file_s/"&FileName<BR>end if <BR>if lcase(right(FileName,3))="doc" then '设置DOC类型文件目录<BR>TrueFileName = "/my_D_O_C_file/"&FileName<BR>end if<BR>if lcase(right(FileName,3))="gif" or lcase(right(FileName,3))="jpg" or lcase(right(FileName,3))="png" then<BR>TrueFileName = "/all_images_/"&FileName '设置图像文件目录<BR>end if<BR>Stream.LoadFromFile Server.MapPath(TrueFileName)<BR>While Not Stream.EOS<BR>Response.BinaryWrite Stream.Read(1024 * 64)<BR>Wend<BR>Stream.Close<BR>Set Stream = Nothing<BR>Response.Flush<BR>Response.End<BR>%></P>
<P>[/quote]</P> 有空了再来研究这个
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