Testing GameAnalytics REST API integration from Haxe

Analytics.hx

import haxe.crypto.Base64;
import haxe.crypto.Hmac;
import haxe.io.Bytes;

class Analytics {
    var game_key :String;
    var secret_key :String;
    
    public function new(game_key :String, secret_key :String) {
        this.game_key = game_key;
        this.secret_key = secret_key;
    }
    
    public function init() {
        var body = '{"platform": "ios", "sdk_version": "rest api v2", "os_version": "ios 8.2"}';
        request(get_url('init'), body);
    }
    
    function get_url(endpoint :String) {
        return 'http://sandbox-api.gameanalytics.com/v2/$game_key/$endpoint';
    }
    
    function request(url :String, body :String) {
        var http = new haxe.Http(url);
        http.onData = function(data :String) {
            var json = haxe.Json.parse(data);
          	trace('Result: ${data}');
            if (json.enabled) trace('enabled!')
            else trace('not enabled');
        };
        http.onStatus = function (status :Int) { trace('Status: $status'); };
        http.onError = function (msg :String) { trace('Error: $msg'); };
        http.addHeader('Content-Type', 'application/json');
        http.addHeader('Authorization', secret_hash(body));
        http.setPostData(body);
        http.async = true;
        http.request();
    }
    
    function secret_hash(body :String) :String {
        return Base64.encode(new Hmac(SHA256).make(Bytes.ofString(secret_key), Bytes.ofString(body)));
    }
}

Test.hx

class Test {
    static function main() {
        var analytics = new Analytics('5c6bcb5402204249437fb5a7a80a4959', '16813a12f718bc5c620f56944e1abc3ea13ccbac');
        analytics.init();
    }
}

/*
Trace:
Status: 200
Result: {"enabled":true,"server_ts":1471645267,"flags":[]}
enabled!
*/