如果我們知道一個靜態文件的實際路徑如：http://www.xx.com/download/51windows.pdf，如果服務器沒有作特別的限制設置，我們就可以毫不費力的把它下載下來！當網站提供51windows.pdf下載時，怎么樣才能讓下載者無法得到他的實際路徑呢！本文就來介紹如何使用asp來隱藏文件的實際下載路徑。

　　我們在管理網站文件時，可以把擴展名一樣的文件放在同一個目錄下，起一個比較特別名字，例如放pdf文件目錄為the_pdf_file_s，把下面代碼另存為down.asp，他的網上路徑為http://www.xx.com/down.asp，我們就可以用http://www.xx.com/down.asp?FileName=51windows.pdf來下載這個文件了，而且下載者無法看到這個文件實際下載路徑的！在down.asp中我們還可以設置下載文件是否需要登陸，判斷下載的來源頁是否為外部網站，從而可以做到防止文件被盜鏈。

示例代碼：

<%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 "非法鏈接！" '防止盜鏈 response.endend ifif Request.Cookies("Logined")="" then response.redirect "/login.asp" '需要登陸！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 "無效文件名！" 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/*" '對圖像文件不出現下載對話框else Response.ContentType = "<a href="http://www.49028c.com/tag-9.html">application</a>/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 '設置pdf類型文件目錄 TrueFileName = "/the_pdf_file_s/"&FileNameend if if lcase(right(FileName,3))="doc" then '設置DOC類型文件目錄 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 '設置圖像文件目錄end ifStream.LoadFromFile Server.MapPath(TrueFileName)While Not Stream.EOS Response.BinaryWrite Stream.Read(1024 * 64)WendStream.CloseSet Stream = NothingResponse.FlushResponse.End%>