Xojo Plugin

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.

Xojo Plugin

Dim success As Boolean
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.

Dim gzip As New Chilkat.Gzip

// Set custom Gzip properties:
gzip.Comment = "Example Gzip file created with Chilkat"
gzip.Filename = "custom_name.txt"
gzip.CompressionLevel = 9
gzip.LastModStr = "Wed, 1 Apr 2025 12:45:26 -0500"

// The file to be compressed:
Dim inputFile As String
inputFile = "example.txt"
Dim outputFile As String
outputFile = "example.txt.gz"

// Compress the file:
success = gzip.CompressFile(inputFile,outputFile)
If (success = False) Then
    System.DebugLog(gzip.LastErrorText)
    Return
End If

System.DebugLog("Compression successful.")
System.DebugLog("Gzip file created: " + outputFile)