I wonder is it a bad pattern to fetch and redirect in ⁠layout. Redirection in ⁠layout means you don't want the user to view the ⁠page. However, I concern about that ⁠layout and ⁠page work simultaneously.

Let's take an example. We need to create several admin pages and block general users from accessing those pages. So, where should the logic for blocking access be located? What about locating this at layout? At first, the intention to call ⁠checkAdmin in layout is to reduce unnecessary fetching in client routing from /admin to /admin/other. I thought check again is unnecessary in client routing under the same layout.

// /app/admin/layout.js
export default async function Layout() {
    const isAdmin = await checkAdmin()

    if (!isAdmin) redirect('/home')

    return <>{children}</>
} 

// /app/admin/page.js
export default async function Page() {
    const credentialData = await fetchApiForAdming()

    return <>{children}</>
}

// /app/admin/other/page.js
export default async function Page() {
    const credentialData = await fetchApiForAdming()

    return <>{children}</>
}

At first glance, it's a quite reasonable choice. Let's go back to the problem that I mentioned at first. In the above code, fetchApiForAdming is called regardless of whether the user is an admin or not. Of course, RSC doesn't return ⁠the credential data and only redirects to ⁠home even if ⁠fetchApiForAdmin throws an error. However, is it appropriate for ⁠fetchApiForAdmin to be called even for requests from regular users, even though it happens server-side and is not transmitted to the client?

Another approach would be to send this logic to middleware, but it is concerning because middleware runs in a separate environment from the app, Edge Runtime, which means caching is not possible.