SEO 완전 정복: 메타데이터 API + JSON-LD + sitemap

// app/posts/[slug]/page.tsx
import type { Metadata } from 'next';

export async function generateMetadata({
  params,
}: {
  params: { slug: string };
}): Promise<Metadata> {
  const post = await getPost(params.slug);

  return {
    title: post.title,
    description: post.excerpt,
    keywords: post.tags,
    authors: [{ name: post.author.name }],
    openGraph: {
      title: post.title,
      description: post.excerpt,
      type: 'article',
      publishedTime: post.publishedAt,
      authors: [post.author.name],
      images: [
        {
          url: post.coverImage,
          width: 1200,
          height: 630,
          alt: post.title,
        },
      ],
    },
    twitter: {
      card: 'summary_large_image',
      title: post.title,
      description: post.excerpt,
      images: [post.coverImage],
    },
    alternates: {
      canonical: `https://example.com/posts/${params.slug}`,
      languages: {
        'en-US': `/en/posts/${params.slug}`,
        'ja-JP': `/ja/posts/${params.slug}`,
      },
    },
  };
}

// app/layout.tsx
export const metadata: Metadata = {
  metadataBase: new URL('https://example.com'),
  title: {
    template: '%s | My Site',
    default: 'My Site — Home',
  },
  description: '기본 설명',
};

// 페이지에선 title: 'Post Title'만 작성
// → "Post Title | My Site" 자동 렌더

// app/posts/[slug]/page.tsx
export default async function Page({ params }: { params: { slug: string } }) {
  const post = await getPost(params.slug);

  const jsonLd = {
    '@context': 'https://schema.org',
    '@type': 'BlogPosting',
    headline: post.title,
    description: post.excerpt,
    author: {
      '@type': 'Person',
      name: post.author.name,
      url: `https://example.com/authors/${post.author.slug}`,
    },
    datePublished: post.publishedAt,
    dateModified: post.updatedAt,
    image: post.coverImage,
    publisher: {
      '@type': 'Organization',
      name: 'My Site',
      logo: { '@type': 'ImageObject', url: 'https://example.com/logo.png' },
    },
  };

  return (
    <>
      <script
        type="application/ld+json"
        dangerouslySetInnerHTML={{ __html: JSON.stringify(jsonLd) }}
      />
      <article>{post.content}</article>
    </>
  );
}

// app/sitemap.ts
import type { MetadataRoute } from 'next';

export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
  const posts = await getAllPosts();

  return [
    {
      url: 'https://example.com',
      lastModified: new Date(),
      changeFrequency: 'daily',
      priority: 1.0,
    },
    {
      url: 'https://example.com/blog',
      lastModified: new Date(),
      changeFrequency: 'daily',
      priority: 0.9,
    },
    ...posts.map(post => ({
      url: `https://example.com/posts/${post.slug}`,
      lastModified: post.updatedAt,
      changeFrequency: 'weekly' as const,
      priority: 0.7,
    })),
  ];
}

// app/robots.ts
import type { MetadataRoute } from 'next';

export default function robots(): MetadataRoute.Robots {
  return {
    rules: [
      { userAgent: '*', allow: '/', disallow: ['/api/', '/admin/', '/private/'] },
      { userAgent: 'GPTBot', disallow: '/' },  // AI 크롤러 차단
    ],
    sitemap: 'https://example.com/sitemap.xml',
  };
}