Visual Basic 6.0

Decode Base64 Image String (GIF, JPG, etc.) and Save to File

I have an XML response that includes a base 64 encoded image string (UPS label). It's a huge string and I need to save it as a gif file on my users pc.

This example shows how to do it..

Visual Basic 6.0

Dim success As Long
success = 0

Dim bd As New ChilkatBinData

' I created an extra-small GIF image for this example..
success = bd.LoadFile("qa_data/gif/xsmall.gif")
If (success <> 1) Then
    Debug.Print "Failed to load GIF image file."
    Exit Sub
End If

' Show GIF bytes as base64:
Debug.Print bd.GetEncoded("base64")

' This particular GIF in base64 is this:
' R0lGODlhBQAFAMQAAAAAAP////z8/PHx8evr6+jo6OHh4d7e3sPDw8LCwpqamo2NjWxsbGRkZFpaWk1NTUtLS0hISCwsLCQkJP///wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACH5BAEAABQALAAAAAAFAAUAAAUTYCAYQUBAU1lI0TIgztE8jFImIQA7

' Let's begin with an XML string:
Dim x As String
x = "<abc><def>R0lGODlhBQAFAMQAAAAAAP////z8/PHx8evr6+jo6OHh4d7e3sPDw8LCwpqamo2NjWxsbGRkZFpaWk1NTUtLS0hISCwsLCQkJP///wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACH5BAEAABQALAAAAAAFAAUAAAUTYCAYQUBAU1lI0TIgztE8jFImIQA7</def></abc>"

Dim xml As New ChilkatXml
success = xml.LoadXml(x)

' Get the base64 string:
Dim gifBase64 As String
gifBase64 = xml.GetChildContent("def")

Debug.Print gifBase64

' Load bd with the base64 decoded bytes.  
success = bd.Clear()
success = bd.AppendEncoded(gifBase64,"base64")

' Save to a GIF file.
success = bd.WriteFile("qa_output/xsmall.gif")