Classic ASP

Resume an Interrupted FTP Transfer

Demonstrates the RestartNext and PartialTransfer properties, which request that the next transfer resume from existing content and report whether a download was incomplete.

Note: The local paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: For a large transfer over a flaky link, restarting from zero after a drop is wasteful. Setting RestartNext makes the next download continue from the current local file size (and the next upload from the remote size); the flag is consumed by that one transfer and then reset. Afterward PartialTransfer tells you whether the download got only part of the file — the signal to set RestartNext again and resume once more.

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Classic ASP

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<%
success = 0

set ftp = Server.CreateObject("Chilkat.Ftp2")

ftp.Hostname = "ftp.example.com"
ftp.Username = "myFtpLogin"

'  Normally you would not hard-code the password in source.  You should instead obtain it
'  from an interactive prompt, environment variable, or a secrets vault.
ftp.Password = "myPassword"

success = ftp.Connect()
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( ftp.LastErrorText) & "</pre>"
    Response.End
End If

'  RestartNext requests that the NEXT transfer resume from existing content rather than starting
'  over.  It is consumed by that transfer and then automatically reset.
ftp.RestartNext = 1

'  Resume a partially-downloaded file.  Because RestartNext is set, the download continues from
'  the current local file size.
success = ftp.GetFile("public_html/bigfile.zip","qa_output/bigfile.zip")
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( ftp.LastErrorText) & "</pre>"
    Response.End
End If

'  PartialTransfer indicates whether the most recent download received some, but not all, of the
'  remote file -- distinguishing a mid-transfer failure from other outcomes.
If (ftp.PartialTransfer) Then
    Response.Write "<pre>" & Server.HTMLEncode( "Only part of the file was received; another resume may be needed.") & "</pre>"
Else
    Response.Write "<pre>" & Server.HTMLEncode( "The file was fully received.") & "</pre>"
End If

success = ftp.Disconnect()
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( ftp.LastErrorText) & "</pre>"
    Response.End
End If


%>
</body>
</html>