Sending Files as Downloads

ASP Tutorials - Herong's Tutorial Examples

∟Sending Files as Downloads

This section provides a tutorial example on how to send files to the Web browser as downloads using the Content-disposition header line.

Another way of sending files to the browser is via attachment. The following ASP page shows you how to do this:

<script language="vbscript" runat="server">
'  download.asp
'  Copyright (c) 2002 by Dr. Herong Yang
   p = request.ServerVariables("QUERY_STRING")
   ok = Len(p)>0
   if (ok) then
      if (InStr(p,".html")>0) then
         contentType = "text/html"
      elseif (InStr(p,".gif")>0) then
         contentType = "image/gif"
      elseif (InStr(p,".pdf")>0) then
         contentType = "application/pdf"
      elseif (InStr(p,".doc")>0) then
         contentType = "application/msword"
      else
         ok = false
      end if
   end if
   r = request.ServerVariables("APPL_PHYSICAL_PATH")
   filePath = r & p
   if (ok) then
      response.Buffer = True
      response.Clear
      response.ContentType = contentType
      response.AddHeader "Content-disposition", _
         "attachment; filename="&p
      set objStream = Server.CreateObject("ADODB.Stream")
      objStream.Open
      objStream.Type = 1 'binar type?
      objStream.LoadFromFile filePath
      response.BinaryWrite objStream.Read
      objStream.Close
      response.Flush
      response.End
   else
      response.Write "<html><body>Error:<br/>"
      response.Write "ApplPhysicalPath = ("&r&")<br/>"
      response.Write "QueryString = ("&p&")<br/>"
      response.Write "</body></html>"
      response.End
   end if
</script>

In this page, another header line, "Content-disposition", is added to the response, in which I am telling the client program that the entity data is an attachment, with file name specified.

Now try to use IE to request: http://localhost:8080/download.asp?hello.pdf, you will see IE prompting you to save the attachment instead of calling Adobe Reader to display the data.