Xojo Plugin

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.

Xojo Plugin

Dim success As Boolean
success = False

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

Dim gzip As New Chilkat.Gzip
Dim bd As New Chilkat.BinData
Dim json As New Chilkat.JsonObject

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

// Get the metadata information from the in-memory Gzip data:
success = gzip.GetGzipInfoBd(bd,json)
If (success = False) Then
    System.DebugLog(gzip.LastErrorText)
    Return
End If

// Output the JSON containing metadata:
System.DebugLog("Gzip metadata JSON:")
System.DebugLog(json.Emit())

// Access individual fields only if they exist:

If (json.HasMember("filename") = True) Then
    Dim filename As String
    filename = json.StringOf("filename")
    System.DebugLog("Filename: " + filename)
End If

If (json.HasMember("comment") = True) Then
    Dim comment As String
    comment = json.StringOf("comment")
    System.DebugLog("Comment: " + comment)
End If

If (json.HasMember("extraData") = True) Then
    Dim extraData As String
    extraData = json.StringOf("extraData")
    System.DebugLog("ExtraData (Base64): " + extraData)
End If