PHP

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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Chilkat2 PHP

<?php

use Chilkat2\Ftp2;

$ftp = new 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';

try {
    $ftp->Connect();

    // 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 = true;

    // Resume a partially-downloaded file.  Because RestartNext is set, the download continues from
    // the current local file size.
    $ftp->GetFile('public_html/bigfile.zip', 'qa_output/bigfile.zip');
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// 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) {
    echo "Only part of the file was received; another resume may be needed.\n";
} else {
    echo "The file was fully received.\n";
}

try {
    $ftp->Disconnect();
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}