(PHP Extension) Set a Custom Last-Modified Date in a Gzip File

See more Gzip Examples

This example demonstrates how to use the SetDt method to specify a custom last-modified date and time that will be embedded in a Gzip file.

A CkDateTime object is first initialized with a specific date/time using an RFC 822 formatted string. This date/time is then applied to the Gzip object using SetDt.

When a compression method is called (such as CompressStringToFile), the specified date/time is included in the Gzip metadata. This allows the resulting .gz file to carry a meaningful timestamp rather than using the current system time.

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<?php

include("chilkat.php");

$success = false;

// This example demonstrates how to set a custom last-modified date/time
// that will be embedded in a Gzip file.

$gzip = new CkGzip();
$dt = new CkDateTime();

// Set the date/time using a timestamp format (ISO 8601 style):
$dt->SetFromTimestamp('2025-11-15T12:45:26-05:00');

// Apply the date/time to the Gzip object:
$success = $gzip->SetDt($dt);
if ($success == false) {
    print $gzip->lastErrorText() . "\n";
    exit;
}

// Compress a string so the custom date/time is embedded in the .gz:
$inputStr = 'Example text for Gzip compression.';
$success = $gzip->CompressStringToFile($inputStr,'utf-8','output.gz');
if ($success == false) {
    print $gzip->lastErrorText() . "\n";
    exit;
}

print 'Gzip file created with custom last-modified date.' . "\n";

?>