How to download the files using vbscript in classic asp

Question

I am working on Classic Asp with VBScript. I am trying to display list of files from a directory with download option. like,

Answer 1

I like this solution, but users can see the downloads in the history, or modify the querystring. This solution can be modified for POST usage this way: in the page code modify the link: FileName` and further down

then in your javascript file get the filename:

    function getfile(obj) {
      var f=obj.innerText;
      $("#frm2dl #file2dl").val(f);
      $("#frm2dl").submit();
    }

alternately you could use a file ID then in the download.asp have a lookup function from ID to filename. Then in the download.asp use request.form("file2dl") instead of request.querystring.

UPDATE: Also, depending on server version you might get the 4MB limit (I have to work with Microsoft-IIS/7.5 on intranet). Therefore for large files the code will not work. Here is my improved version:

Dim strFileName, strFilePath, objFSO, objStream, objFile, intFileSize
Const lChkSize = 524288 ' 500KB - server typical limit is 4MB 
'If session("loggedIn") = True Then ' insert your logon validation code here. bypassed for testing
    strFileName = request.form("file2dl")
    strFilename = Replace(strFilename,"..","") ' prevent parent path navigation - also ensure uploaded files do not contain this sequence
    strFilename = Replace(strFilename,"/","") ' prevent path navigation
    strFilename = Replace(strFilename,"\","") ' filenames should already be cleaned by a previous process
    strFilePath = server.MapPath("/insert your URL absolute sources filepath here/" & strFilename)
    Set objFSO = Server.CreateObject("Scripting.FileSystemObject")
    If objFSO.FileExists(strFilePath) Then
        Set objFile = objFSO.GetFile(strFilePath)
        intFileSize = objFile.Size
        Set objFile = Nothing
        Response.AddHeader "Content-Disposition","attachment; filename=" & strFileName
        Response.ContentType = "application/x-msdownload"
        Response.AddHeader "Content-Length", intFileSize
        Set objStream = Server.CreateObject("ADODB.Stream")
        objStream.Type = 1 'adTypeBinary
        objStream.Open
        objStream.LoadFromFile strFilePath
        Do While Not objStream.EOS And Response.IsClientConnected
            Response.BinaryWrite objStream.Read(lChkSize)
            Response.Flush()
        Loop
        objStream.Close
        Set objStream = Nothing
    Else
        Response.write "Error finding file: " & request.form("file2dl")
    End if
    Set objFSO = Nothing
'End If