import 'dart:convert'; class UploadURL { final String url; final String objectKey; UploadURL(this.url, this.objectKey); Map toMap() { return { 'url': url, 'objectKey': objectKey, }; } factory UploadURL.fromMap(Map map) { if (map == null) return null; return UploadURL( map['url'], map['objectKey'], ); } String toJson() => json.encode(toMap()); factory UploadURL.fromJson(String source) => UploadURL.fromMap(json.decode(source)); }