Get a github gist with dart (flutter)

getgist.dart

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


class GistFile {
  String name;
  String rawurl;
  String _content = "";
  bool truncated; 
  
  GistFile(this.name, this.rawurl, this.truncated);
  
  void setContent(content) {
    _content = content;
  }
  
  Future<String> getContent() async {
    String fcontent = _content;
    if (truncated) {
      final response = await http.get(Uri.parse(rawurl));
      if (response.statusCode == 200) {
        fcontent = response.body;
        truncated = false;
      } else {
        throw Exception('Failed to get raw file ${rawurl} (http ${response.statusCode})');
      }
    } 
    return fcontent;
  }
}

class Gist {
  late String id;
  late String description;
  late DateTime createdAt;
  late DateTime updatedAt;
  late String ownerLogin;
  late int ownerId;
  
  late List<GistFile> files;

  Gist.fromJson(Map json) {
    id = json['id'];
    description = json['description'];
    createdAt = DateTime.parse(json["created_at"]);
    updatedAt = DateTime.parse(json["updated_at"]);
    ownerId = json['owner']['id'];
    ownerLogin = json['owner']['login'];
    
    files = [];

    var fmap = json['files'];

    var ftype = "YAML";
    
    fmap.keys.forEach((k) {
      if (fmap[k]["language"] == ftype) {
        GistFile gistFile = GistFile(fmap[k]["filename"], 
                                     fmap[k]["raw_url"],
                                     fmap[k]["truncated"],
                                     );
        if (!fmap[k]["truncated"]) {
          gistFile.setContent(fmap[k]["content"]);
        }
        files.add(gistFile);
      }
    });
  }
}


Future<Gist> fetchGist(id) async {
  final response = await http
      .get(Uri.parse("https://api.github.com/gists/${id}"));

  if (response.statusCode == 200) {
    return Gist.fromJson(jsonDecode(response.body));
  } else {
    throw Exception('Failed to load gist ${id} (http ${response.statusCode})');
  }
}

void main() {
  String id = "cf24237b13eb9584738247fc43a5addc";

 
  Future<Gist> fg = fetchGist(id);
  fg.then((g) {
    print(g.description);
    print(g.createdAt);
    print(g.updatedAt);
    print(g.ownerId);
    print(g.ownerLogin);
    
    g.files.forEach((f) {
      print(f.name);
      print(f.rawurl);

      f.getContent().then((c) { print(c); });
    });
  });
  
}