VB.NET

Extract data:image/png;base64 from HTML

See more Base64 Examples

Demonstrates how to extract base64 image data from HTMl and save to files. VB.NET

Dim success As Boolean = False

Dim sb As New Chilkat.StringBuilder
Dim bd As New Chilkat.BinData
Dim sbFilename As New Chilkat.StringBuilder
Dim index As Integer = 1

success = sb.LoadFile("qa_data/html/oresp body.txt","utf-8")
' Assume success.
Debug.WriteLine("length = " & sb.Length)

Dim mayHaveMore As Boolean = True
While mayHaveMore = True

    ' Get the base64 between the 1st occurrence "data:image/png;base64," and "'"
    Dim sBase64 As String = sb.GetBetween("data:image/png;base64,","'")

    ' If nothing is found, then we'll exit the loop because there are no more.
    mayHaveMore = sb.LastMethodSuccess

    If (sb.LastMethodSuccess = True) Then
        ' Found something.
        ' Load into bd and save.
        success = bd.LoadEncoded(sBase64,"base64")

        sbFilename.SetString("qa_output/png_")
        sbFilename.AppendInt(index)
        sbFilename.Append(".png")

        bd.WriteFile(sbFilename.GetAsString())

        ' Replace "data:image/png;base64" with "data:image-png;base64" so the next iteration finds the next occurrence.
        sb.ReplaceFirst("data:image/png;base64","data:image-png;base64")
    End If


    index = index + 1
End While

' Restore our replacements..
Dim count As Integer = sb.Replace("data:image-png;base64","data:image/png;base64")

Debug.WriteLine("All done.")