craft 0.1.0

Provides Oauth clients with token auto-refresh support, queueing requests, offline support

example/craft_example.dart

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

class LoginData implements Serializable {
  final String username;
  final String password;

  const LoginData(this.username, this.password);

  @override
  Json toJson() {
    return <String, dynamic>{
      'username': username,
      'password': password,
    };
  }
}

class ApiService {
  static ApiService? _instance;
  static ApiService get instance => _instance!;

  ApiService._({required BaseCraft craft}) : _craft = craft;

  factory ApiService({required BaseCraft craft}) {
    if (_instance != null) throw StateError('Already created');

    _instance = ApiService._(craft: craft);
    return instance;
  }

  late BaseCraft _craft;

  Future<void> login(LoginData loginData) async {
    final http.Response response = await _craft.send(
      Request<LoginData>(
        HttpMethod.post,
        Uri.parse('https://example.com/login'),
        body: loginData,
      ),
    );

    final TokenPair tokenPair = _tokensFromLoginResponse(response);

    _craft = PersistableAutoRefreshingBearerOauthCraft(
      tokens: tokenPair,
      refreshTokenMethod: _refreshTokens,
      tokenExpiration: _tokenExpiration,
      tokenStorageKey: 'craft_example_token_storage_key',
    );
  }

  // Can be made private because it is unnecessary to call it manually. If
  // needed, it can of course be public as well.
  //
  // We assume here that only new access token is issued and refresh token stays
  // the same.
  Future<TokenPair> _refreshTokens(String refreshToken) async {
    final http.Response response = await _craft.send(
      Request<String>.fromString(
        HttpMethod.post,
        'https://example.com/login/refresh',
        body: refreshToken,
      ),
    );

    final String newAccessToken = response.body;
    return TokenPair(newAccessToken, refreshToken);
  }

  Duration _tokenExpiration(String accessToken) {
    return Duration(
      milliseconds: _parseExpirationMsFromJwtToken(accessToken) -
          DateTime.now().millisecondsSinceEpoch,
    );
  }

  // Returns dummy tokens for example purposes. This would usually be a method
  // that parses tokens from response body.
  TokenPair _tokensFromLoginResponse(http.Response response) {
    return const TokenPair('access', 'refresh');
  }

  // Returns dummy expiration ms since epoch. This would usually be extracted
  // from 'iat' JWT value.
  int _parseExpirationMsFromJwtToken(String jwtToken) {
    return DateTime.now().millisecondsSinceEpoch + 60000;
  }
}