Example Structure

// Copyright (c) 2015, <your name>. All rights reserved. Use of this source code
// is governed by a BSD-style license that can be found in the LICENSE file.

/// The SiaIExx library.
library SiaIExx;

import 'dart:async';
import 'dart:convert';
import 'package:http/http.dart' as http;

// Classes

class HostStatus{
  int TotalStorage;
  int MinFilesize;
  int Price;
  // rest of props
  HostStatus(_totalStorage, _minFileSize, _price):
    TotalStorage = _totalStorage, MinFilesize = _minFileSize, Price = _price;
  HostStatus copy(){
    return new HostStatus(TotalStorage, MinFilesize, Price);
  }
}


// Variables

HostStatus latestHostStatus;


// "Getters"

HostStatus getHostStatus(){
  return latestHostStatus.copy();
}


// Timer approach
void updateGlobalVariables(Timer t){
    http.get("localhost:9980/host/status").then((response){
      var json = JSON.decode(response.body);
      latestHostStatus.TotalStorage = json["TotalStorage"];
      // rest of props
    });
}

main(){
  Duration duration = new Duration(milliseconds:500);
  new Timer.periodic(duration, updateGlobalVariables);
}