VBScript

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.

VBScript

Dim fso, outFile
Set fso = CreateObject("Scripting.FileSystemObject")
'Create a Unicode (utf-16) output text file.
Set outFile = fso.CreateTextFile("output.txt", True, True)

success = 0

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

set gzip = CreateObject("Chilkat.Gzip")
set dt = CreateObject("Chilkat.CkDateTime")

' Set the date/time using a timestamp format (ISO 8601 style):
success = dt.SetFromTimestamp("2025-11-15T12:45:26-05:00")

' Apply the date/time to the Gzip object:
success = gzip.SetDt(dt)
If (success = 0) Then
    outFile.WriteLine(gzip.LastErrorText)
    WScript.Quit
End If

' 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 = 0) Then
    outFile.WriteLine(gzip.LastErrorText)
    WScript.Quit
End If

outFile.WriteLine("Gzip file created with custom last-modified date.")

outFile.Close