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Gaute Meek Olsen
Gaute Meek Olsen

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Vue, guard routes with Firebase Authentication

With Vue Router you might want to guard som paths and redirect users to a signup page if they are not authenticated. I will show you how this is done correctly with Firebase Authentication.

This article assumes you already have implemented your project with Vue Router and Firebase Authentication

First, we must mark each route that we want to guard with a meta property called requiresAuth.

const routes = [
  {
    path: '/signin',
    name: 'signin',
    component: () => import('../views/SignIn.vue')
  },
  {
    path: '/profile',
    name: 'profile',
    component: () => import('../views/Profile.vue'),
    meta: {
      requiresAuth: true
    }
  }
]

In this example, the path /signin is allowed for everyone, but /profile should only be for signed-in users.

Now we can use the beforeEach guard to check for this property.

router.beforeEach(async (to, from, next) => {
  const requiresAuth = to.matched.some(record => record.meta.requiresAuth);
  if (requiresAuth && !currentUser){
    next('signin');
  }else{
    next();
  }
});

Now if the currentUser is null or undefined, we should redirect users to the signin path. But how do we get currentUser? We can’t use firebase.auth().currentUser because on page refresh that property has not been set yet before the guard is triggered. We will have to use the onAuthStateChanged callback somehow. Let’s add a method to the firebase object after we initialize the firebase app.

firebase.initializeApp(firebaseConfig);

firebase.getCurrentUser = () => {
    return new Promise((resolve, reject) => {
        const unsubscribe = firebase.auth().onAuthStateChanged(user => {
            unsubscribe();
            resolve(user);
        }, reject);
    })
};

This method will return a Promise which resolves currentUser as soon as it is set. onAuthStateChangedwill trigger the callback immediately with either null or the user object if signed in. Then we unsubscribe to not listen for further changes.

Now we will update our beforeEach guard so that only paths that require authentication await this method.

router.beforeEach(async (to, from, next) => {
  const requiresAuth = to.matched.some(record => record.meta.requiresAuth);
  if (requiresAuth && !await firebase.getCurrentUser()){
    next('signin');
  }else{
    next();
  }
});

That’s all. This also simplifies getting the currentUser for components under the guarded routes, because we know firebase.auth().currentUser is set.

For full example check out this GitHub repository and demo at vue-routes-authentication.web.app

Discussion (9)

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frederickirchhoff profile image
Frederic Kirchhoff

This is awesome! This is a major issue (I ended up thinking I will have to write my entire app in a single file to avoid that auth problem) and I am surprised I haven't found an elegant solution like that anywhere else on the web!

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tarkhil profile image
tarkhil

Seems to be the most complete and elaborated example on the subject

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tarkhil profile image
tarkhil

The next problem, I'm trying to fight it on github.com/tarkhil/authts is that RouterGuard does nothing on the first request to the router.
I have no idea what I could make wrong. But now it's 100% repeatable for me

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kaguya3222 profile image
Maxim Anisimov

Thank you! You've made my day!

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tarkhil profile image
tarkhil

Unfortunately, firebase.getCurrentUser = () requires something additional in TypeScript and I did not get answer yet

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gautemeekolsen profile image
Gaute Meek Olsen Author

Usually, TS won't let you add a method to another object without something additional.

But maybe you can just assign the method to a new variable instead:

const getCurrentUser = () => {
    return new Promise((resolve, reject) => {
        const unsubscribe = firebase.auth().onAuthStateChanged(user => {
            unsubscribe();
            resolve(user);
        }, reject);
    })
};
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chromaticranger profile image
Martin Stickley

I can confirm that this approach worked for me in TS. :-) Many thanks @gautemeekolsen for sharing this knowledge.

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arafel profile image
Paul Walker

That just saved me from probably several hours of trying to figure out how to solve it, and I still wouldn't have done it as elegantly as that. :-) Thanks!

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matheusmacedoap profile image
Matheus Macedo

Me ajudou muito... algo simples e direto!!!

Parabéns!!!