Caching Strategy

// 1. Request Memoization — same fetch in same render is deduped
// Both components fetching /api/user share ONE request per render
fetch("/api/user")  // component A
fetch("/api/user")  // component B — same URL = single request

// 2. Data Cache — persists across requests and deployments
fetch(url, { cache: "force-cache" });        // indefinitely cached (default for GET)
fetch(url, { cache: "no-store" });           // never cache
fetch(url, { next: { revalidate: 60 } });   // cache 60 seconds

// 3. Full Route Cache — static routes cached at build time
export const revalidate = 3600; // revalidate whole route every 1 hour
export const dynamic = "force-dynamic"; // opt out of full route cache

// 4. Router Cache — client-side cache of visited routes
import { useRouter } from "next/navigation";
router.refresh();  // clear router cache for current route

// On-demand revalidation
import { revalidatePath, revalidateTag } from "next/cache";
revalidatePath("/products");           // clear all /products pages
revalidateTag("products");             // clear fetches tagged 'products'

// Static blog posts — cached forever, revalidated when author publishes
// app/blog/[slug]/page.tsx
export const revalidate = false;  // cache indefinitely

export async function generateStaticParams() {
  const posts = await db.posts.findMany({ select: { slug: true } });
  return posts.map(p => ({ slug: p.slug }));
}

// Server Action triggered by CMS webhook
export async function revalidatePost(slug: string) {
  "use server";
  revalidatePath(`/blog/${slug}`);    // clear specific post
  revalidatePath("/blog");              // clear blog index
  revalidatePath("/");                  // clear homepage (shows recent posts)
}

// API endpoint for CMS to call
// app/api/revalidate/route.ts
export async function POST(request: Request) {
  const body = await request.json();
  const secret = request.headers.get("x-webhook-secret");
  if (secret !== process.env.REVALIDATE_SECRET) {
    return Response.json({ error: "Invalid secret" }, { status: 401 });
  }
  revalidatePath(`/blog/${body.slug}`);
  return Response.json({ revalidated: true });
}