Objective-C

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..

Objective-C

#import <CkoBinData.h>
#import <NSString.h>
#import <CkoXml.h>

BOOL success = NO;

CkoBinData *bd = [[CkoBinData alloc] init];

// I created an extra-small GIF image for this example..
success = [bd LoadFile: @"qa_data/gif/xsmall.gif"];
if (success != YES) {
    NSLog(@"%@",@"Failed to load GIF image file.");
    return;
}

// Show GIF bytes as base64:
NSLog(@"%@",[bd GetEncoded: @"base64"]);

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

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

CkoXml *xml = [[CkoXml alloc] init];
success = [xml LoadXml: x];

// Get the base64 string:
NSString *gifBase64 = [xml GetChildContent: @"def"];

NSLog(@"%@",gifBase64);

// Load bd with the base64 decoded bytes.  
[bd Clear];
[bd AppendEncoded: gifBase64 encoding: @"base64"];

// Save to a GIF file.
success = [bd WriteFile: @"qa_output/xsmall.gif"];