Authenticated routes using react-router

This post is very old and contains obsolete information.

Here’s a simple walk through on how to use authenticated routes with react-router.

create-react-app route-test
cd route-test
yarn add react-router-dom

And for src/App.js:

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import React, { Component } from "react";
import { BrowserRouter as Router, Route, Link, Switch } from "react-router-dom";

const Nav = () => (
  <ul>
    <li>
      <Link to="/">Home</Link>
    </li>
    <li>
      <Link to="/about">About</Link>
    </li>
    <li>
      <Link to="/session">Session</Link>
    </li>
    <li>
      <Link to="/secret">Secret</Link>
    </li>
  </ul>
);

const Welcome = () => (
  <div>
    <h1>Welcome</h1>
    <p>This is some text</p>
  </div>
);

const About = () => (
  <div>
    <h1>About</h1>
    <p>Sure, stuff</p>
  </div>
);

const Secret = () => (
  <div>
    <h1>This is a secret</h1>
    <p>Sorry, not everyone can see this</p>
  </div>
);

const Session = ({ login }) => (
  <div>
    <button onClick={login}>Click me</button>
  </div>
);

class App extends Component {
  state = { login: false };
  login = () => {
    this.setState({ login: true });
  };

  render() {
    return (
      <Router>
        <div>
          <Nav />
          {this.state.login && <p>Logged in</p>}
          <Switch>
            <Route path="/secret" component={Secret} />
            <Route path="/about" component={About} />
            <Route
              path="/session"
              component={() => <Session login={this.login} />}
            />
            <Route component={Welcome} />
          </Switch>
        </div>
      </Router>
    );
  }
}

export default App;

We are using Stateless Functional Components to model out our nav bar, and a few pages.
Link is what we use to create a link to something that we define in our router. This needs to be a child of a Router, so our Nav component must be a child of that.
Switch is where we are putting out routes to keep everything nice and tidy.
We have a very simple login system here, where if you go to /session and push a button, you are considered logged in.

Secret isn’t so secret

Lets create an authenticated component. The idea is that if the user is not authenticated, we will redirect to /session which will show whatever login form we have.

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

class AuthenticatedRoute extends Component {
  render() {
    const { authed, component: Component, ...rest } = this.props;

    if (authed) {
      return <Route {...rest} render={(props) => <Component {...props} />} />;
    } else {
      return (
        <Route
          {...rest}
          render={(props) => (
            <Redirect
              to={{ pathname: "/session", state: { from: props.location } }}
            />
          )}
        />
      );
    }
  }
}

export default AuthenticatedRoute;

Now we just need to update the switch to use the new AuthenticatedRoute. We are passing in an authed property that the main App component is maintaining.

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<AuthenticatedRoute authed={this.state.login} path=”/secret” component={Secret}/>

Now we need to update the Session component to handle the login. In the case that we aren’t logged in, we show a button that calls the login method on the container component. This will change the login state and trigger a rerender of the components. Once that happens, authed will be true so we look inside of the location property to see if there was a protected route stored in the router history state. If so, we redirect back to that. Otherwise, we redirect back to home.

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const Session = ({ authed, location, login }) => {
  if (authed) {
    let l = location.location;
    let pathname = "/";
    if (l && l.state && l.state.from) {
      pathname = l.state.from.pathname;
    }
    return <Redirect to={pathname} />;
  } else {
    return (
      <div>
        <button
          onClick={() => {
            login();
          }}
        >
          Click me
        </button>
      </div>
    );
  }
};

And finally, we need to wire all this up in the main routes.

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<Route path="/session" render={(location) => <Session location={location} login={this.login} authed={this.state.authed}/> }/> } />

Here we aren’t just passing in component={Session} but rather a function that gets wired up to a number of local callbacks. This is mainly so that the login function can call setState and then trigger the render. In a case where this would be something that came from a server, you could use the normal asynchronous methods and not need to force this directly.