PowerShell

Detect End-of-File on a Remote SFTP File

Demonstrates the Chilkat SFtp.Eof method, which returns whether the most recent read for a handle received the SFTP end-of-file status. The only argument is the handle. This example reads until Eof is true.

Background: The timing here is worth understanding: reading exactly through the final byte does not immediately set EOF. The next read succeeds, returns zero bytes, sets the status to SSH_FX_EOF, and only then does Eof report true. That is why the loop tests Eof after each read rather than assuming a short read means the end — a short read can also just be the server returning less than requested.

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Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

#  Demonstrates the SFtp.Eof method, which returns whether the most recent read for a handle
#  received the SFTP end-of-file status.  The only argument is the handle.

$sftp = New-Object Chilkat.SFtp

#  Connect, authenticate, and initialize the SFTP subsystem.
$port = 22
$success = $sftp.Connect("sftp.example.com",$port)
if ($success -eq $false) {
    $($sftp.LastErrorText)
    exit
}

#  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.
$password = "mySshPassword"

$success = $sftp.AuthenticatePw("mySshLogin",$password)
if ($success -eq $false) {
    $($sftp.LastErrorText)
    exit
}

$success = $sftp.InitializeSftp()
if ($success -eq $false) {
    $($sftp.LastErrorText)
    exit
}

$handle = $sftp.OpenFile("subdir/data.txt","readOnly","openExisting")
if ($sftp.LastMethodSuccess -eq $false) {
    $($sftp.LastErrorText)
    exit
}

#  Read until Eof reports the end of the file.  Note that reading exactly through the final byte
#  does not set EOF; the next read returns zero bytes and then Eof becomes true.
$sbContent = New-Object Chilkat.StringBuilder
$chunkSize = 4096
$reading = $true
while ($reading) {
    $chunk = $sftp.ReadFileText($handle,$chunkSize,"utf-8")
    if ($sftp.LastReadFailed($handle)) {
        $($sftp.LastErrorText)
        exit
    }

    $sbContent.Append($chunk)
    $reading = !$sftp.Eof($handle)
}

$success = $sftp.CloseHandle($handle)
if ($success -eq $false) {
    $($sftp.LastErrorText)
    exit
}

$($sbContent.GetAsString())

$sftp.Disconnect()