AutoIt

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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AutoIt

Local $bSuccess = False

$oFtp = ObjCreate("Chilkat.Ftp2")

$oFtp.Hostname = "ftp.example.com"
$oFtp.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.
$oFtp.Password = "myPassword"

$bSuccess = $oFtp.Connect()
If ($bSuccess = False) Then
    ConsoleWrite($oFtp.LastErrorText & @CRLF)
    Exit
EndIf

;  RestartNext requests that the NEXT transfer resume from existing content rather than starting
;  over.  It is consumed by that transfer and then automatically reset.
$oFtp.RestartNext = True

;  Resume a partially-downloaded file.  Because RestartNext is set, the download continues from
;  the current local file size.
$bSuccess = $oFtp.GetFile("public_html/bigfile.zip","qa_output/bigfile.zip")
If ($bSuccess = False) Then
    ConsoleWrite($oFtp.LastErrorText & @CRLF)
    Exit
EndIf

;  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 ($oFtp.PartialTransfer) Then
    ConsoleWrite("Only part of the file was received; another resume may be needed." & @CRLF)
Else
    ConsoleWrite("The file was fully received." & @CRLF)
EndIf

$bSuccess = $oFtp.Disconnect()
If ($bSuccess = False) Then
    ConsoleWrite($oFtp.LastErrorText & @CRLF)
    Exit
EndIf