PureBasic

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.

PureBasic

IncludeFile "CkGzip.pb"

Procedure ChilkatExample()

    success.i = 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.

    gzip.i = CkGzip::ckCreate()
    If gzip.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Set custom Gzip properties:
    CkGzip::setCkComment(gzip, "Example Gzip file created with Chilkat")
    CkGzip::setCkFilename(gzip, "custom_name.txt")
    CkGzip::setCkCompressionLevel(gzip, 9)
    CkGzip::setCkLastModStr(gzip, "Wed, 1 Apr 2025 12:45:26 -0500")

    ; The file to be compressed:
    inputFile.s = "example.txt"
    outputFile.s = "example.txt.gz"

    ; Compress the file:
    success = CkGzip::ckCompressFile(gzip,inputFile,outputFile)
    If success = 0
        Debug CkGzip::ckLastErrorText(gzip)
        CkGzip::ckDispose(gzip)
        ProcedureReturn
    EndIf

    Debug "Compression successful."
    Debug "Gzip file created: " + outputFile


    CkGzip::ckDispose(gzip)


    ProcedureReturn
EndProcedure