B4X Requires Chilkat v11.5.0+

Retrieve Metadata from Gzip Data in Memory (BinData)

This example demonstrates how to use the GetGzipInfoBd method to retrieve metadata from Gzip data stored in memory within a BinData object.

The Gzip data is first loaded into the BinData instance. The GetGzipInfoBd method then extracts any available metadata from the Gzip header, including the embedded filename, comment, and optional extra data.

The metadata 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.

B4X

Dim success As Boolean = False

'  This example demonstrates how to retrieve metadata from Gzip data
'  stored in a BinData object.

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

'  Load a Gzip file into BinData:
success = bd.LoadFile("example.txt.gz")
If success = False Then
    Log(bd.LastErrorText)
    Return
End If


'  Get the metadata information from the in-memory Gzip data:
success = gzip.GetGzipInfoBd(bd, 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