medium_03_custom_http_client.dart

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

class AuthenticatedHttpClient extends http.BaseClient {
  SharedPreferences sharedPref;
  AuthenticatedHttpClient({this.sharedPref});

  // Use a memory cache to avoid local storage access in each call
  String _inMemoryToken = '';
  String get userAccessToken {
    // use in memory token if available
    if (_inMemoryToken.isNotEmpty) return _inMemoryToken;

    // otherwise load it from local storage
    _inMemoryToken = _loadTokenFromSharedPreference();

    return _inMemoryToken;
  }

  @override
  Future<http.StreamedResponse> send(http.BaseRequest request) {
    // intercept each call and add the Authorization header if token is available
    if (userAccessToken.isNotEmpty) {
      request.headers.putIfAbsent('Authorization', () => userAccessToken);
    }

    return request.send();
  }

  String _loadTokenFromSharedPreference() {
    var accessToken = '';
    final user = sharedPref.getString(CACHED_USER);

    // If user is already authenticated, we can load his token from cache
    if (user != null) {
      accessToken = user.accessToken;
    }
    return accessToken;
  }

  // Don't forget to reset the cache when logging out the user
  void reset() {
    _inMemoryToken = '';
  }
}

Hello! Thx for the code. Why don't you reset the "_inMemoryToken" along with sharedPref CACHED_USER on log out?

Hi! We have a different class that is responsible for reseting all the sharedPref variables. In this case we'd preferred to only reset variables related to (owned by) the HttpClient. Besides it was a precaution in case you want to start using more than a single AuthenticatedHttpClient instance

But do what works better/(makes more sense) to your project :D 👍

Hello! Thx for the code. Why don't you reset the "_inMemoryToken" along with sharedPref CACHED_USER on log out?

Hi! We have a different class that is responsible for reseting all the sharedPref variables. In this case we'd preferred to only reset variables related to (owned by) the HttpClient. Besides it was a precaution in case you want to start using more than a single AuthenticatedHttpClient instance

But do what works better/(makes more sense) to your project :D 👍

Thank you very much! 🤝🏻