Ch5. Next.js App Router 엔터프라이즈 패턴

// apps/web/next.config.ts
import type { NextConfig } from 'next';

const config: NextConfig = {
  async rewrites() {
    return {
      beforeFiles: [
        {
          source: '/admin/:path*',
          destination: `${process.env.ADMIN_URL}/admin/:path*`,
        },
        {
          source: '/docs/:path*',
          destination: `${process.env.DOCS_URL}/docs/:path*`,
        },
      ],
    };
  },
};

export default config;

// next.config.ts
import type { NextConfig } from 'next';

const nextConfig: NextConfig = {
  cacheComponents: true,
};

export default nextConfig;

// app/products/[id]/page.tsx
'use cache';

import { cacheLife, cacheTag } from 'next/cache';

export default async function ProductPage({ params }: { params: Promise<{ id: string }> }) {
  const { id } = await params;
  cacheLife('hours');
  cacheTag(`product-${id}`);
  const product = await fetchProduct(id);
  return <ProductDetail product={product} />;
}

// app/api/webhook/route.ts
import { revalidateTag } from 'next/cache';

export async function POST(request: Request) {
  const { type, id } = await request.json();

  if (type === 'product.updated') {
    revalidateTag(`product-${id}`);  // 특정 태그만 무효화
  }

  return Response.json({ revalidated: true });
}

// proxy.ts
import { NextResponse } from 'next/server';
import type { NextRequest } from 'next/server';

export function proxy(request: NextRequest) {
  // 1. 인증 체크
  const token = request.cookies.get('session_token');
  if (request.nextUrl.pathname.startsWith('/admin') && !token) {
    return NextResponse.redirect(new URL('/login', request.url));
  }

  // 2. A/B 테스트
  const bucket = request.cookies.get('ab_bucket')?.value
    ?? (Math.random() < 0.5 ? 'a' : 'b');

  const response = NextResponse.next();
  if (!request.cookies.get('ab_bucket')) {
    response.cookies.set('ab_bucket', bucket, { maxAge: 60 * 60 * 24 * 30 });
  }
  response.headers.set('x-ab-bucket', bucket);
  return response;
}

export const config = {
  matcher: ['/((?!_next/static|_next/image|favicon.ico).*)'],
};

// app/settings/actions.ts
'use server';

import { getDb } from '@acme/db';
import { revalidatePath } from 'next/cache';
import { z } from 'zod';

const schema = z.object({
  name: z.string().min(1).max(100),
  email: z.string().email(),
});

export async function updateProfile(formData: FormData) {
  const parsed = schema.safeParse(Object.fromEntries(formData));
  if (!parsed.success) {
    return { error: parsed.error.flatten().fieldErrors };
  }
  const db = getDb();
  await db.user.update({
    where: { id: getCurrentUserId() },
    data: parsed.data,
  });
  revalidatePath('/settings');
  return { success: true };
}

// app/api/users/route.ts
import { getDb } from '@acme/db';

export async function GET(request: Request) {
  const { searchParams } = new URL(request.url);
  const page = Number(searchParams.get('page') ?? '1');
  const db = getDb();

  const users = await db.user.findMany({
    take: 20,
    skip: (page - 1) * 20,
    orderBy: { createdAt: 'desc' },
  });

  return Response.json({ data: users, page });
}

// Edge Runtime 명시
export const runtime = 'edge';

// Node.js Runtime (기본값)
export const runtime = 'nodejs';

// app/products/[id]/page.tsx
'use cache'

export default async function ProductPage({ params }: { params: Promise<{ id: string }> }) {
  const { id } = await params;
  const product = await fetchProduct(id);
  return <ProductDetail product={product} />;
}