/* Download Large Binary Files via ASP:  
      Take large binary files and send them down through the a browser.

 Copyright:
      2007-2008, Karland International (www.karland.com/www.chizl.com)

 Permission:
      Permission to use, copy, modify, distribute and sell this software and its 
      documentation for any purpose is hereby granted without fee, provided that the 
      above copyright notice appears in all copies and that both that copyright notice 
      and this permission notice appear in supporting documentation. Karland International 
      makes no representations about the suitability of this software for any purpose. 
      It is provided "as is" without express or implied warranty.
*/

	Response.Buffer = True
  
	Const adTypeBinary = 1

	Dim objFile
	Dim iFileSize, iChunkSize, iFileLeft
	Dim strFilePath
	
	strFilePath = "C:\ExcelFiles\Excel1.xls" 'This is the path to the file on disk. 

	'Set the content type to the specific type that you are sending.

	Set objFile = objFSO.GetFile(strFilePath)
	'get file size

	iFileSize = objFile.Size
	iFileLeft = iFileSize
	
	'set file name

	Response.AddHeader "Content-Disposition", "attachment; filename=" & objFile.Name
	'set file size

	Response.AddHeader "Content-Length", iFileSize
	'set file type

	Response.ContentType = "application/x-msexcel"
	
	Set objStream = Server.CreateObject("ADODB.Stream")
	objStream.Open
	objStream.Type = adTypeBinary
	
	objStream.LoadFromFile strFilePath
	
	'do until end of stream or client disconnects

	Do While Not objStream.EOS Or Not Response.IsClientConnected
		'if the chunk size is larger than the size of data left to be sent, shrink the chunk size

		If iChunkSize > iFileLeft Then iChunkSize = iFileLeft
		
		'write to browser

		Response.BinaryWrite(objStream.Read(iChunkSize))
		'flush the response buffer or it will not go past 4MB

		Response.Flush
		'figure out whats left of the file

		iFileLeft = iFileLeft - iChunkSize
	Loop
	
	'clean up

	objStream.Close
	Set objStream = Nothing
	Set objFile = Nothing