Delphi DLL

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..

Delphi DLL

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, BinData, Xml;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
bd: HCkBinData;
x: PWideChar;
xml: HCkXml;
gifBase64: PWideChar;

begin
success := False;

bd := CkBinData_Create();

// I created an extra-small GIF image for this example..
success := CkBinData_LoadFile(bd,'qa_data/gif/xsmall.gif');
if (success <> True) then
  begin
    Memo1.Lines.Add('Failed to load GIF image file.');
    Exit;
  end;

// Show GIF bytes as base64:
Memo1.Lines.Add(CkBinData__getEncoded(bd,'base64'));

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

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

xml := CkXml_Create();
success := CkXml_LoadXml(xml,x);

// Get the base64 string:
gifBase64 := CkXml__getChildContent(xml,'def');

Memo1.Lines.Add(gifBase64);

// Load bd with the base64 decoded bytes.  
CkBinData_Clear(bd);
CkBinData_AppendEncoded(bd,gifBase64,'base64');

// Save to a GIF file.
success := CkBinData_WriteFile(bd,'qa_output/xsmall.gif');

CkBinData_Dispose(bd);
CkXml_Dispose(xml);

end;