Flash messages are null when using a try/catch block to conditionally redirect the user

[finestgecko]

I'm following the guide for validating server side forms but it's unclear how to conditionally redirect a user:

• Successful login: redirect to /dashboard
• Failed login: redirect back to /login where the flash message can be shown.

With the code below, {{ inspect(flashMessages.all()) }} is always null.

public async login({ auth, request, session, response }: HttpContextContract) {
    const email = request.input('email')
    const password = request.input('password')

    try {
      await auth.use('web').attempt(email, password)
      return response.redirect('/dashboard')
    } catch {
      return response.redirect('/login')
    }
}

I wondered if error messages should be set manually with session.flash(), but in the example in the docs, the error flash messages are not explicitly set.

If I try without the try/catch block and send the user back to the login page regardless of successful/failed login, I get redirected to / rather than /login:

public async login({ auth, request, session, response }: HttpContextContract) {
    const email = request.input('email')
    const password = request.input('password')

    await auth.use('web').attempt(email, password)

    return response.redirect('/login')
}

Here are my routes:

Route.get('/', async ({ view }) => view.render('index'))
Route.get('/login', async ({ view }) => view.render('login'))
Route.get('/signup', async ({ view }) => view.render('signup'))

Route.post('/login', 'AuthController.login')
Route.post('/users/create', 'UsersController.create')

Route.group(() => {
  Route.get('/dashboard', async ({ view, auth }) => view.render('dashboard', { user: auth.user }))
}).middleware('auth:web')

I would be grateful for any advice.

[finestgecko]

Solved:

When I used request.validate() to create a user, I did not need to explicitly define flash messages, this was handled behind the scenes.

For some reason, I had the assumption that this would also happen with auth.use('web').attempt(email, password), but it seems this is not the case.

In this instance, flash messages should be manually created using session.flash().