Custom file downloads in ASP

Downloads can be downloaded (memory, less) or go directly to the file.

<%

Constuse_stream=0 ' 0. No flow (adodb.stream) Download 1. Use the Shed to load
constallow_file_ext= "Rar,zip,chm,doc,xls,swf,mp3,gif,jpg,jpeg,png,bmp" ' allows downloading of file extensions to prevent source code from being downloaded

Dimsdownfilepath ' Download file path
Sdownfilepath=trim (Request ("FilePath"))
' or get the file path from the database based on the file ID passed in.

' If Sdownfilepath is an absolute path, be sure to convert the Sdownfilepath to a relative path relative to this file

' Sdownfilepath= ' focus.swf '

Calldownloadfile (Sdownfilepath)

Functiondownloadfile (S_downfilepath)
' Judge if there is no pass file name
Ifisnull (S_downfilepath) =trueortrim (S_downfilepath) = "" Then
Outputerr "ERROR: First determine the file to download, download failed"
EndIf

' Determine if the extension is legitimate
Dims_fileext
S_fileext=mid (S_downfilepath,instrrev (S_downfilepath, ".") +1)
Ifinstr ("," &ALLOW_FILE_EXT& ",", "," &s_FileExt& ",") <=0then
Outputerr "Error: File type (" &s_FileExt& ") is not allowed to be downloaded, download failed"
EndIf

S_downfilepath=replace (S_downfilepath, "", "/")

' For security, some directories prohibit downloading files, processing here
'

' Detect if the server supports FSO
Dimo_fso
Onerrorresumenext
Seto_fso=server.createobject ("Scripting.FileSystemObject")
Iferr.number<>0then
Err.Clear
Outputerr "Error: Server does not support FSO component, download failed"
EndIf

    ' get filename, file size
   dims_filemappath
   dimo_file,s_ Filename,n_filelength
   s_filemappath=server.mappath (s_downfilepath)
    If (O_fso.fileexists (S_filemappath)) =truethen
       seto_file=o_ Fso.getfile (S_filemappath)
       s_filename=o_file.name
        n_filelength=o_file.size
       o_ File.close
   else
       outputerr "error: File does not exist, download failed"
   endif
   seto_fso=nothing

' Determines whether the downloaded file size exceeds the limit
'

' If it's not streamed, go directly to the file
Ifuse_stream=0then
Response.redirectsdownfilepath
Response.End
EndIf

' Detect if the server supports ADODB.stream
Onerrorresumenext
Seto_stream=server.createobject ("ADODB.stream")
Iferr.number<>0then
Err.Clear
Outputerr "Error: Server does not support ADODB.stream component, download Failed"
EndIf

O_stream.tyep=1
O_stream.open
O_stream.loadfromfiles_filemappath

Response.buffer=true
Response.Clear
Response.AddHeader "Content-disposition", "Attachment;filename=" &s_filename
Response.AddHeader "Content-length", n_filelength
response.charset= "UTF-8"
Response.contenttype= "Application/octet-stream"
Response.BinaryWriteo_Stream.Read
Response.Flush

O_stream.close
Seto_stream=nothing

Endfunction

Suboutputerr (S_ERRMSG)
Response.Write "<fontcolor=red>" &s_ErrMsg& "</font>"
Response.End
Endsub

%>

Http://www.cnblogs.com/jiny-z/archive/2006/08/29/489102.html