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HTML / CSS / JS

// lib/auth.ts — cached auth check shared across Server Components
import { cache } from 'react';
import { cookies } from 'next/headers';
import { verifySession } from '@/lib/session';

// cache() ensures this runs at most once per request
// even if called from multiple Server Components
export const getUser = cache(async () => {
  const cookieStore = cookies();
  const sessionToken = cookieStore.get('session')?.value;

if (!sessionToken) return null;

const session = await verifySession(sessionToken);
  return session?.user ?? null;
});

// app/dashboard/page.tsx
import { getUser } from '@/lib/auth';
import { redirect } from 'next/navigation';

export default async function DashboardPage() {
  const user = await getUser(); // cached — no duplicate DB query
  if (!user) redirect('/login');

return <h1>Welcome, {user.name}</h1>;
}

// app/dashboard/layout.tsx
import { getUser } from '@/lib/auth';

export default async function DashboardLayout({
  children,
}: {
  children: React.ReactNode;
}) {
  const user = await getUser(); // same cached call — no extra query
  return (
    <div>
      <nav>Logged in as {user?.email}</nav>
      {children}
    </div>
  );
}