Making Private Route in Flutter

Question

How can I make a wrapper over my private routes, which navigate to screen only when user is authorized, otherwise redirect to login and get back to the original screen after login. How can make this in a generalized way, so that I just reuse it on my other Private future screens?

Answer 1

If you are using routes parameter in your MaterialApp, you can replace it with following implementation

import 'dart:collection';

import 'package:flutter/widgets.dart';

class ConditionalRouter extends MapMixin<String, WidgetBuilder> {
  final Map<String, WidgetBuilder> public;
  final Map<String, WidgetBuilder> private;

  ConditionalRouter({this.public, this.private});

  @override
  WidgetBuilder operator [](Object key) {
    if (public.containsKey(key))
      return public[key];
    if (private.containsKey(key)) {
      if (MyAuth.isUserLoggedIn)
        return private[key];
      // Adding next page parameter to your Login page
      // will allow you to go back to page, that user were going to
      return (context) => LoginPage(nextPage: key);
    }
    return null;
  }

  @override
  void operator []=(key, value) {}

  @override
  void clear() {}

  @override
  Iterable<String> get keys {
    final set = Set<String>();
    set.addAll(public.keys);
    set.addAll(private.keys);
    return set;
  }

  @override
  WidgetBuilder remove(Object key) {
    return public[key] ?? private[key];
  }
}

And use it like that:

MaterialApp(
  // ...
  routes: ConditionalRouter(
    public: {
      '/start_page': (context) => StartPage()
    },
    private: {
      '/user_profile': (context) => UserProfilePage()
    }
  )
)

Answer 2

Use StreamBuilder widget and provide it a Stream of access token/uid if there is no data then return login screen and when user is authenticated then put access token into the stream that will rebuild the StreamBuilder which return the page when user is authenticated.

Use bloc pattern or bloc library for better state management. Hope this will help you.

Answer 3

Generalised idea, you could make the controller a Static variable

class LoginController{
  final Function onContactingServerDone;
  LoginController({this.onContactingServerDone,});

  bool loggedIn;

  login()async {
    //contact server,get token or verify token etc

    onContactingServerDone();
  }
}

and in your screen

LoginController _loginController;
initState(){
  _loginController = LoginController(onContactingServerDone: (){
    if(_loginController.loggedIn){
      Navigator.of(context).pushNamed('privateRoute');
    } else {
      Navigator.of(context).pushNamed('login');
    }
  },);
  _loginController.login();
}

Widget build(context){
  return CircularProgressIndicator();
}