Redirect on Login - React.js

Question

I am trying to do a simple Redirect with React Router after my user successfully logs in (inside Login.js), and prevent the user from revisiting the login page (inside index.js).

In Login.js, I have onSubmit={this.handleSubmit} within the login button tag, and handleSubmit(e) function to Redirect. I have tried a few other solutions online, but I think my understanding on the usage of the <Redirect/> component is wrong.

In index.js, I have a conditional that tests if the user is signed in, or not signed in, and (poorly) alerts the user on why they can't visit the desired page. I saw this in a Youtube video, but not sure if it's the best way to get the desired effect.

Currently, when I log in successfully, the alert You can't login if you are logged in! is set off, but I obviously don't want the alert going off right after a successful login, I want the Redirect to trigger first. If I swap the two in the parenthesis, React throws an error.

How do I get the Redirect to trigger right after a successful login, but not send the alert You can't login if you are logged in!?

Login.js Component:

import React, { Component } from 'react';
import fire from '../config/Fire.js';
import { Link, Redirect } from 'react-router-dom';
import PasswordMask from 'react-password-mask';

export default class Login extends Component {
    constructor(props) {
        super(props);
        this.login = this.login.bind(this);
        this.handleChange = this.handleChange.bind(this);
        this.handleSubmit = this.handleSubmit.bind(this);
        this.signup = this.signup.bind(this);
        this.state = {
          email: '',
          password: ''
        };
      }

    handleChange(e) {
        this.setState({ [e.target.name]: e.target.value });
    }

    handleSubmit(e) {
        e.preventDefault();
        <Redirect to="/ticket-list"/>;
    }

    login(e) {
        e.preventDefault();
        fire.auth().signInWithEmailAndPassword(this.state.email, this.state.password).catch((error) => {
            alert(error);
            });
    }

    signup(e){
        e.preventDefault();
        fire.auth().createUserWithEmailAndPassword(this.state.email, this.state.password).catch((error) => {
            alert(error);
            })
    }

    render() {
        return (
        <div className="m-container">
            <h1>Login</h1>
            <hr/>
            <div className="m-container">
                <form onSubmit={this.submitForm}>
                <div>
                    <label for="exampleInputEmail1">Email address: </label>
                    <br/>
                    <input 
                    value={this.state.email} 
                    onChange={this.handleChange} 
                    type="text" 
                    name="email" 
                    id="exampleInputEmail1" 
                    placeholder="[e-mail]" />
                </div>
                <div>
                    <label for="exampleInputPassword1">Password: </label>
                    <br/>
                    {/* Margin issue when showing and hiding password */}
                    <PasswordMask 
                    value={this.state.password} 
                    onChange={this.handleChange} 
                    type="password" 
                    name="password" 
                    id="exampleInputPassword1" 
                    placeholder="**********"
                     />
                </div>
                <br/>
                <button 
                    type="submit" 
                    className="button" 
                    onClick={this.login}
                    onSubmit={this.handleSubmit}>Login</button>
                &nbsp;
                <Link className="button-inv" to="/register">Register</Link>
                </form>
            </div>
        </div>
        );
    }
}

index.js Component:

import React, { Component } from 'react';
import { Route, Switch, Redirect } from 'react-router-dom';

import Home from './Home';
import Technician from './Technician';
import About from './About';
import Register from './Register';
import Login from './Login';
import TicketList from './TicketList';

export default class Routes extends Component {

    render() {
        return (
        <Switch>
            <Route path="/" exact component={Home} />
            <Route path="/technician" exact component={Technician} />
            <Route path="/about" exact component={About} />
            <Route path="/register" exact render={()=>(
                this.props.user ? (alert("You can't register if you are logged in!"), (<Redirect to="/"/>)) : (<Register/>)
            )} />
            <Route path="/login" exact render={()=>(
                this.props.user ? (alert("You can't login if you are logged in!"), (<Redirect to="/ticket-list"/>)) : (<Login/>)
            )} />
            <Route path="/ticket-list" exact render={()=>(
                this.props.user ? (<TicketList/>) : (alert("You must log in to visit this page."), (<Redirect to="/login"/>))
            )} />
        </Switch>
        );
    }
};

App.js:

import React, { Component } from 'react';
import { BrowserRouter } from 'react-router-dom';
import Routes from './routes';
import fire from './config/Fire.js';

// CSS
import './assets/css/App.css';
import './assets/css/Header.css';
import './assets/css/Footer.css';
// Components
import Header from './components/Header';
import Footer from './components/Footer';

class App extends Component {
  constructor(props){
    super(props);
    this.state = {
      user:{},
    }
  }

  //When component is done rendering for the first time
  componentDidMount(){
    this.authListener();
  }

  // If user logs in (if) or out (else) this is called
  authListener() {
    fire.auth().onAuthStateChanged((user) => {
      //console.log(user);
      if (user) {
        this.setState({ user });
      } else {
        this.setState({ user: null });
      }
    });
  }


  render() {
    return (
      <BrowserRouter>
        <div className="wrapper">
          <Header user={this.state.user} />
          <div className="body">
            <Routes user={this.state.user} />
          </div>
          <Footer />
        </div>
      </BrowserRouter>
    );
  }
}

export default App;

Answer 1

To solve your problem you have to create separate components for Login/Register and make alerts and redirects there depends on user. You will need High Order Component named withRouter from react-router lib.

Login container:

class LoginContainer extends Component {
  constructor(props) {
    super(props)

    if (props.user) {
      alert("You can't login if you are logged in!")
      props.history.push('/ticket-list')
    }
  }

  render() {
    return <Login />;
  }
}

export default withRouter(LoginContainer)

And then use it in your Routes like this:

<Route path="/login" render={()=> <LoginContainer user={this.props.user} />} />

The same one for Register or you can just make one and get params like alertMessage and redirectTo and use them instead of hardcoded values.

In addition, I advice you to use auth HoC for your private routes, which is not accessible without authentication.

I'd prefer to use new context API for sharing such entity as user, localization, etc, so here is an example how to make PrivateRoute using React Context API.

App.js

...
export const UserContext = React.createContext();
...
class App extends Component {

    state = {
        user: null
    }

    componentDidMount() {
      this.authListener();
    }

    authListener() {
      fire.auth().onAuthStateChanged(user => {
        if (user) {
          this.setState({ user });
        }
      });
    }

    render() {
       <UserContext.Provider value={this.state}>
           <BrowserRouter>
               // another things Switch etc
               ...
           </BrowserRouter>
       </UserContext.Provider>
    }
}

PrivateRoute.jsx

import React, { Component } from 'react';
import { Route, Redirect } from 'react-router-dom'
import { UserContext } from './App'

const PrivateRoute = ({ component: ComposedComponent, ...rest }) => {

  class Authentication extends Component {

    handleRender = props => {
      if (!this.props.user) {
        return <Redirect to="/login" />
      } else {
        return <ComposedComponent user={this.props.user} {...props} />
      }
    }

    render() {
      return (
        <Route {...rest} render={this.handleRender} />
      );
    }
  }

  return (
    <UserContext.Consumer>
      {
        ({ user }) => <Authentication user={user} />
      }
    </UserContext.Consumer>
  )
};

export default PrivateRoute

And then you can use PrivateRoute instead of Route in case when you don't want to show page without authentication.

import PrivateRoute from './PrivateRoute'

...

// all of the component code
render() {
    ...
    <Switch>
        <PrivateRoute path="/ticket-list" component={<TicketList />} />
    </Switch>
    ...
}

Hope it helps! Good luck!

Answer 2

You can use:

<Redirect push to="/somewhere/else"/>

Answer 3

as the official documentation says, you should create a Private router

this is an example of how I am implementing it using local storage to see if the user data is there or not then redirecting back to the login page if the data is not there. this can be reused in all of your components!

import { BrowserRouter as Router, Route, Redirect, Switch } from 'react-router-dom';

import Login from './views/login';
import Supportedmodels from './views/dashboard/supported-models';


const PrivateRoute = ({ component: Component, ...rest }) => 
(  
  <Route {...rest} render={props => 
  (
    localStorage.getItem('user') ? <Component {...props} /> : <Redirect to={{pathname: '/login'}}/>
  )}/>
);

function App() 
{
  return (

    <Router>
      <Switch>
        <PrivateRoute path="/" component={Supportedmodels} exact />

        <Route path="/login" component={Login} />
      </Switch>      
    </Router>
  );
}

to read more here is the link https://reacttraining.com/react-router/web/example/auth-workflow