Revalidation

// Time-based revalidation (ISR)
await fetch(url, { next: { revalidate: 60 } }); // revalidate every 60 seconds
 
// Tag-based fetching
await fetch(url, { next: { tags: ["products"] } });
 
// On-demand revalidation by tag
import { revalidateTag } from "next/cache";
revalidateTag("products");
 
// On-demand revalidation by path
import { revalidatePath } from "next/cache";
revalidatePath("/products");        // revalidate a specific page
revalidatePath("/products", "layout"); // revalidate layout and all child pages
revalidatePath("/", "layout");         // revalidate the entire app

// lib/products.ts
export async function getProducts() {
  const res = await fetch("https://api.example.com/products", {
    next: { revalidate: 300, tags: ["products"] },
  });
  if (!res.ok) throw new Error("Failed to fetch products");
  return res.json() as Promise<Product[]>;
}
 
export async function getProduct(slug: string) {
  const res = await fetch(`https://api.example.com/products/${slug}`, {
    next: { tags: ["products", `product-${slug}`] },
  });
  if (!res.ok) throw new Error("Product not found");
  return res.json() as Promise<Product>;
}

// app/actions/product.ts
"use server";
 
import { revalidateTag, revalidatePath } from "next/cache";
import { db } from "@/lib/db";
 
export async function updateProduct(formData: FormData) {
  const slug = formData.get("slug") as string;
  const name = formData.get("name") as string;
  const price = Number(formData.get("price"));
 
  await db.product.update({
    where: { slug },
    data: { name, price },
  });
 
  // Revalidate just this product's cached data
  revalidateTag(`product-${slug}`);
 
  // Also revalidate the product listing page
  revalidatePath("/products");
}
 
export async function deleteProduct(slug: string) {
  await db.product.delete({ where: { slug } });
 
  // Revalidate all product-related caches
  revalidateTag("products");
}

// app/api/revalidate/route.ts -- webhook-triggered revalidation
import { revalidateTag } from "next/cache";
import { NextRequest, NextResponse } from "next/server";
 
export async function POST(request: NextRequest) {
  const secret = request.headers.get("x-revalidation-secret");
  if (secret !== process.env.REVALIDATION_SECRET) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
  }
 
  const { tag } = await request.json();
  revalidateTag(tag);
 
  return NextResponse.json({ revalidated: true, tag });
}

// app/products/layout.tsx
// All pages under /products revalidate every 5 minutes
export const revalidate = 300;

import { unstable_cache } from "next/cache";
import { db } from "@/lib/db";
 
const getCachedUser = unstable_cache(
  async (id: string) => db.user.findUnique({ where: { id } }),
  ["user-cache"],
  { tags: ["users"], revalidate: 600 }
);

// app/dashboard/page.tsx
export const dynamic = "force-dynamic";

// revalidatePath signature
function revalidatePath(
  originalPath: string,
  type?: "layout" | "page"
): void;
 
// revalidateTag signature
function revalidateTag(tag: string): void;
 
// Segment config export types
export const revalidate: number | false = 60;
export const dynamic: "auto" | "force-dynamic" | "force-static" | "error" = "auto";