Paano gumagana ang on-demand revalidation (ISR)?

Question

Accepted Answer

**On-demand revalidation** yana ba ka bugi cached/static shafuka **jiya lokacin da bayyanar ta canja** — maimakon jira ga lokaci da ke da tsari. Shine daidai gida ga lokaci-da ke tsari ISR (`revalidate: N`).

## Lokaci-da ke tsari da on-demand

```tsx
// Time-based: page refreshes on a fixed schedule (may serve stale data up to N seconds)
export const revalidate = 3600; // every hour

// On-demand: refresh the INSTANT the underlying data changes — no waiting, no waste
```

Lokaci-da ke tsari ISR shi ne mai sauƙi amma ba shi cikakke ba: gajere = jiya ba daidai ba; dogon lokaci = tsohuwar abin. On-demand ya gyara haka ta hanyar kitsa revalidation daga naka alama lokacin da canja ya auka.

## APIs biyu na on-demand

```tsx
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");
```

## Ainihi na aiki: CMS webhook

```ts
// 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 });
}
```

Raguwa: editon na CMS ya buga → CMS ta kira webhook din → `revalidateTag("posts")` ya bugi cache → bisitoci na gida ya karbi freshly regenerated static HTML. Shafuka suna nan tsattsatse-sauri **da** update nan-nan a bugu.

## Bayan Server Action mutation

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

## Me ya sa ya ma-muhimma

On-demand revalidation yana ba ka abin da dake zama mafi girma: **sauri na static tare da freshness na tunau**.

Instead of tunanin revalidation interval, ka bugi daidai lokacin da abun ya canja — ta hanyar webhooks (CMS bugu) ko bayan Server Action mutations — ta amfani da `revalidateTag`/`revalidatePath`.

Yana cire duka tsohuwar abin da kuma rashin amfani da over-regeneration, yana sa ISR kasancewa mai amfani ga abin da ke canja ba tare da kirki ba.