supabase/examples/auth/nextjs-auth/pages/profile.js

import Link from 'next/link'
import { supabase } from '../utils/initSupabase'

export default function Profile({ user }) {
  return (
    <div style={{ maxWidth: '520px', margin: '96px auto' }}>
      <h4>You're signed in</h4>
      <h5>Email: {user.email}</h5>
      <hr />

      <div style={{ color: 'green' }}>
        User data retrieved server-side (from Cookie in getServerSideProps):
      </div>
      <div>
        <pre>{JSON.stringify(user, null, 2)}</pre>
      </div>

      <div>
        <Link href="/">
          <a>Static example with useSWR</a>
        </Link>
      </div>
    </div>
  )
}

export async function getServerSideProps({ req }) {
  const { user } = await supabase.auth.api.getUserByCookie(req)

  if (!user) {
    // If no user, redirect to index.
    return { props: {}, redirect: { destination: '/', permanent: false } }
  }

  // If there is a user, return it.
  return { props: { user } }
}