B4X Requires Chilkat v11.5.0+

Retrieve Metadata from a Gzip File

See more Gzip Examples

This example demonstrates how to use the GetGzipInfo method to retrieve metadata embedded within a Gzip file.

The method reads the Gzip header and extracts any available metadata, including the embedded filename, comment, and optional extra data. The extracted information is returned in a JsonObject.

Because these fields are optional, the example checks for the existence of each JSON member using HasMember before retrieving its value. This avoids attempting to access values that may not be present.

B4X

Dim success As Boolean = False

'  This example demonstrates how to retrieve metadata embedded in a Gzip file.

Dim gzip As ChilkatGzip
gzip.Initialize("gzip")
Dim json As ChilkatJsonObject
json.Initialize

'  The Gzip file to examine:
Dim gzPath As String = "example.txt.gz"

'  Get the metadata information:
success = gzip.GetGzipInfo(gzPath, json)
If success = False Then
    Log(gzip.LastErrorText)
    Return
End If


'  Output the JSON containing metadata:
Log("Gzip metadata JSON:")
Log(json.Emit)

'  Access individual fields only if they exist:

If json.HasMember("filename") = True Then
    Dim filename As String = json.StringOf("filename")
    Log("Filename: " & filename)
End If


If json.HasMember("comment") = True Then
    Dim comment As String = json.StringOf("comment")
    Log("Comment: " & comment)
End If


If json.HasMember("extraData") = True Then
    Dim extraData As String = json.StringOf("extraData")
    Log("ExtraData (Base64): " & extraData)
End If