JavaScript

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..

JavaScript

var success = false;

var bd = new CkBinData();

// I created an extra-small GIF image for this example..
success = bd.LoadFile("qa_data/gif/xsmall.gif");
if (success !== true) {
    console.log("Failed to load GIF image file.");
    return;
}

// Show GIF bytes as base64:
console.log(bd.GetEncoded("base64"));

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

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

var xml = new CkXml();
success = xml.LoadXml(x);

// Get the base64 string:
var gifBase64 = xml.GetChildContent("def");

console.log(gifBase64);

// Load bd with the base64 decoded bytes.  
bd.Clear();
bd.AppendEncoded(gifBase64,"base64");

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