Checking auth token valid before route enter in Vue router

Question

I have a simple use case, where my application is using vue-router and vuex. Then store contains a user object which is null in the beginning. After the user is validated from the server it sends back an user object which contains a JWT auth token which is assigned to the user object in the store. Now lets assume that the user came back after 3 hours and tried to visit a route or perform any other action, considering that the auth token has expired by then, what would be the best way to check that(need to call axios post to check it) and redirect user to the login page. My app will have loads of components so I know I can write logic to check the token valid in the mounted hook of each component but that would mean repeating it all of the components. Also I don't want to use the beforeEach navigation guard because I cannot show any visual feedback to the user like checking... or loading....

Answer 1

I do something similar in one of my projects, it's actually deceptively difficult to handle these types of situations, but you can add a beforeEnter guard to your protected routes, then redirect if the authentication failed.

const guard = function(to, from, next) {
  // check for valid auth token
  axios.get('/api/checkAuthToken').then(response => {
      // Token is valid, so continue
      next();
  }).catch(error => {
      // There was an error so redirect
      window.location.href = "/login";
  })
};

Then on your route you can do:

{
  path: '/dashboard',
  component: Dashboard,
  beforeEnter: (to, from, next) => {
    guard(to, from, next);
  }
},

You may notice I've used location.href rather than router.push. I do that because my login form is csrf protected, so I need a new csrf_token.

Your other issue is going to be if the user tries to interact with your page without changing the route (i.e. they click a button and get a 401 response). For this I find it easiest to check authentication on each axios request and redirect to login when I receive a 401 response.

In terms of adding a loading spinner during the guard check you can simply add a loading flag to your vuex store then import your store into your router. Honestly though I wouldn't bother, on a decent production server the check will be done so quickly that the user is unlikely to ever see it.