(PHP Extension) Compress a File to Gzip with Custom Metadata

See more Gzip Examples

This example demonstrates how to use the CompressFile method to create a Gzip (.gz) file while customizing the metadata embedded in the Gzip header.

Before compression, several properties are set:

• Comment: Adds a descriptive comment to the Gzip file.
• Filename: Specifies the filename to embed in the Gzip data, which may be used by extraction tools as the default output name.
• CompressionLevel: Controls the tradeoff between compression ratio and speed (set to maximum in this example).
• LastModStr: Sets the last-modified timestamp using an RFC 822 formatted date string.

After setting these properties, the input file is compressed and written to a .gz file. This approach allows you to embed meaningful metadata along with the compressed data.

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<?php

include("chilkat.php");

$success = false;

// This example demonstrates how to compress a file to Gzip format
// while setting custom metadata such as comment, filename,
// compression level, and last-modified date.

$gzip = new CkGzip();

// Set custom Gzip properties:
$gzip->put_Comment('Example Gzip file created with Chilkat');
$gzip->put_Filename('custom_name.txt');
$gzip->put_CompressionLevel(9);
$gzip->put_LastModStr('Wed, 1 Apr 2025 12:45:26 -0500');

// The file to be compressed:
$inputFile = 'example.txt';
$outputFile = 'example.txt.gz';

// Compress the file:
$success = $gzip->CompressFile($inputFile,$outputFile);
if ($success == false) {
    print $gzip->lastErrorText() . "\n";
    exit;
}

print 'Compression successful.' . "\n";
print 'Gzip file created: ' . $outputFile . "\n";

?>