Xbase++

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.

Xbase++

LOCAL nSuccess
LOCAL oGzip
LOCAL cInputFile
LOCAL cOutputFile

nSuccess := 0

//  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.

oGzip := CreateObject("Chilkat.Gzip")

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

//  The file to be compressed:
cInputFile := "example.txt"
cOutputFile := "example.txt.gz"

//  Compress the file:
nSuccess := oGzip:CompressFile(cInputFile, cOutputFile)
IF (nSuccess == 0)
    ? oGzip:LastErrorText
    oGzip:destroy()
    RETURN
ENDIF

? "Compression successful."
? "Gzip file created: " + cOutputFile

oGzip:destroy()