How to pass auth token to every request after login or signup - Dio flutter - flutter

Question

This is an easy method to save the auth token from login and signup to pass to every other request. You just have to pass the token right in the initialization of "Dio". In my method I use Dio interceptor onResponse function to save the auth token to SharedPreference. Please do share other better methods.
class ApiSerivce {
late Dio dio;
late SharedPreferences prefs;
var token = '';
//
ApiSerivce() {
dio = Dio(BaseOptions(
baseUrl: BaseApi.baseUrl,
sendTimeout: 10000,
receiveTimeout: 10000,
));
tokenCheck();
intitialInterceptor();
}
tokenCheck() async {
prefs = await SharedPreferences.getInstance();
token = prefs.getString('token') ?? token;
}
intitialInterceptor() {
GlobalKey<NavigatorState>? navigator;
dio.interceptors.add(InterceptorsWrapper(
onError: (error, handler) {
print('dio error :::::: ' + error.message.toString());
if (error.response?.statusCode == 400) {
print('dio ::::::: auth not valid');
navigator?.currentState?.pushReplacementNamed('login');
}
print('dio error :::::: ' + error.response.toString());
return handler.next(error);
},
onRequest: (request, handler) {
request.headers['Cookie'] = "jwt=$token";
print('dio request path :::::: ' + request.headers.toString());
return handler.next(request);
},
onResponse: (response, handler) {
if (response.realUri.toString().contains('login') ||
response.realUri.toString().contains('signUp')) {
if (response.statusCode == 200 || response.statusCode == 201) {
token = response.data['token'];
setToken(response.data['token'].toString());
}
}
return handler.next(response);
},
));
}
}
setToken(String token) async {
final prefs = await SharedPreferences.getInstance();
prefs.setString('token', token);
}