オンデマンド再検証 (ISR) はどのように機能するのか?

import { revalidatePath, revalidateTag } from "next/cache";

// 1. Tag your fetches, then invalidate by tag
await fetch("https://api/posts", { next: { tags: ["posts"] } });
revalidateTag("posts");      // refresh EVERY page/fetch tagged "posts"

// 2. Or invalidate a specific path
revalidatePath("/blog/my-post");

// app/api/revalidate/route.ts — called by your CMS when an editor publishes
import { revalidateTag } from "next/cache";
import { NextRequest, NextResponse } from "next/server";

export async function POST(req: NextRequest) {
  const secret = req.nextUrl.searchParams.get("secret");
  if (secret !== process.env.REVALIDATE_SECRET) {       // verify it's really your CMS
    return NextResponse.json({ ok: false }, { status: 401 });
  }
  revalidateTag("posts");                                // rebuild affected pages now
  return NextResponse.json({ revalidated: true });
}

"use server";
export async function createPost(data) {
  await db.post.create({ data });
  revalidateTag("posts"); // user sees their new post immediately
}