When will revalidate works?

[past wave]

When I send in the header like

headers: {
            next: { revalidate: 600 },
          },

it will only work on server side? Does it also work in generateMetadata, generateStaticParams? It will not work in client-side hooks like useEffect right? It will just ignore this setting on client-side?

[waxen tundra]

Hi @past wave. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave:

---

Revalidation in Next.js is primarily a server-side feature and does not work on the client side. Here are the key points regarding revalidation based on the provided knowledge sources:

1. Server-Side Revalidation:

   • Revalidation settings like revalidate are used to control how often a static page is regenerated. For example, setting revalidate to 600 means the page will be regenerated every 600 seconds.
   • This setting is typically used in server-side functions like getStaticProps or API routes.

2. Client-Side Revalidation:

   • Revalidation settings do not apply to client-side hooks like useEffect. The client-side will ignore these settings.
   • To immediately invalidate the client-side cache, you would need to use methods like revalidatePath, revalidateTag in a server action, or router.refresh() (source (https://github.com/vercel/next.js/issues/57451)).

3. Usage in generateMetadata and generateStaticParams:

   • The revalidate setting can be used in server-side functions, but it is not explicitly mentioned in the provided sources whether it works in generateMetadata or generateStaticParams. However, it is implied that generateStaticParams is used for static generation and does not revalidate during ISR (source (https://github.com/vercel/next.js/issues/59883)).

4. Example of Server-Side Revalidation:

   import { NextApiRequest, NextApiResponse } from 'next';
   
   export default async function handler(req: NextApiRequest, res: NextApiResponse) {
     // Checking for available method
     if (req.method !== 'POST') {
       return res.status(404).json({ error: `Invalid method ${req.method}` });
     }
   
     // Checking body
     if (!req.body.subdomain) {
       return res.status(401).send({ error: 'Missing subdomain on body' });
     }

// Revalidating route
try {
await res.revalidate(/${req.body.subdomain}); // Next.js method to recreate static pages

   res.status(200).json({ ok: true, subdomain: req.body.subdomain, headers: req.headers });
 } catch (error) {
   res.status(500).json({ error, headers: req.headers });
 }

}

For more detailed information, you can refer to the **Next.js documentation on On-Demand Revalidation** (<https://nextjs.org/docs/pages/building-your-application/data-fetching/incremental-static-regeneration#on-demand-revalidation>).
----------------------
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@past wave kapa.ai is still learning and improving, please let us know how it did by reacting below

[past wave]

@waxen tundra if I do not send { revalidate: 600 }, means it will cache forever until on demand revalidation?

[waxen tundra]

Let me check the knowledge base for you. One moment! :books:

---

If you do not specify a revalidate value, the default behavior depends on the context in which you are working. Here are the key points based on the provided knowledge sources:

1. Default Behavior Without revalidate:

   • If you do not set a revalidate value, Next.js will use the default value of false, which means the page will not be revalidated automatically and will be cached indefinitely until an on-demand revalidation is triggered.
   • This is equivalent to setting revalidate to Infinity.

2. On-Demand Revalidation:

   • You can manually trigger revalidation using methods like revalidatePath or revalidateTag to purge the cache and fetch fresh data.
   • On-demand revalidation allows you to update your site when specific events occur, such as content updates from a CMS or changes in eCommerce metadata.

3. Example of On-Demand Revalidation:

   import { NextApiRequest, NextApiResponse } from 'next';
   
   export default async function handler(req: NextApiRequest, res: NextApiResponse) {
     // Checking for available method
     if (req.method !== 'POST') {
       return res.status(404).json({ error: `Invalid method ${req.method}` });
     }
   
     // Checking body
     if (!req.body.subdomain) {
       return res.status(401).send({ error: 'Missing subdomain on body' });
     }
   
     // Revalidating route
     try {
       await res.revalidate(`/${req.body.subdomain}`); // Next.js method to recreate static pages
   
       res.status(200).json({ ok: true, subdomain: req.body.subdomain, headers: req.headers });
     } catch (error) {
       res.status(500).json({ error, headers: req.headers });
     }
   }
   

For more detailed information, you can refer to the Next.js documentation on On-Demand Revalidation (https://nextjs.org/docs/pages/building-your-application/data-fetching/incremental-static-regeneration#on-demand-revalidation).

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon:

@past wave kapa.ai is still learning and improving, please let us know how it did by reacting below

[past wave]

@waxen tundra setting { revalidate: 0 } is the same as no caching?

[waxen tundra]

Let me check the knowledge base for you. One moment! :books:

---

Yes, setting { revalidate: 0 } is effectively the same as no caching. When you set revalidate to 0, it ensures that the resource is not cached at all. This is equivalent to setting the cache option to 'no-store'.

Here are the key points based on the provided knowledge sources:

1. revalidate: 0:

   • Prevents the resource from being cached.
   • Equivalent to setting cache: 'no-store'.

2. Behavior:

   • When revalidate is set to 0, the resource will always be fetched fresh and will not be stored in the cache.
   • This setting is useful for dynamic content that should not be cached, such as frequently changing data or sensitive information.

3. Example Usage:

   fetch('<https://example.com/api/data',> {
     next: { revalidate: 0 }
   });
   

4. Good to Know:

   • If you set revalidate to a number greater than 0, it specifies the cache lifetime in seconds.
   • Conflicting options such as { revalidate: 0, cache: 'force-cache' } will cause an error.

For more detailed information, you can refer to the Next.js documentation on fetch options (https://nextjs.org/docs/app/api-reference/functions/fetch#optionsnextrevalidate).

Here is a relevant extract from the documentation:

• 0 - Prevent the resource from being cached.
• As a convenience, it is not necessary to set the cache option if revalidate is set to a number since 0 implies cache: 'no-store' and a positive value implies cache: 'force-cache'.

For more details, you can check the Next.js documentation on fetch options (https://nextjs.org/docs/app/api-reference/functions/fetch#optionsnextrevalidate).

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon:

@past wave kapa.ai is still learning and improving, please let us know how it did by reacting below

[past wave]

@waxen tundra are POST requests cached as well? Do I need to set { revalidate: 0 } to prevent it from caching

[waxen tundra]

Let me check the knowledge base for you. One moment! :books:

---

Yes, POST requests can be cached in Next.js under certain circumstances. However, there are specific conditions where POST requests are not cached. Here are the key points based on the provided knowledge sources:

1. Caching Behavior of POST Requests:

   • By default, POST requests can be cached if they return a 200 OK status code.
   • POST requests are not cached if they are made inside a dynamic route handler or if certain dynamic methods are used before the request.

2. Preventing Caching for POST Requests:

   • To ensure that a POST request is not cached, you can set the revalidate option to 0 or use the cache: 'no-store' option.

3. Conditions Where POST Requests Are Not Cached:

   • If the request is inside a route handler that uses the POST method.
   • If the request comes after the usage of headers or cookies.
   • If the revalidate option is set to 0.
   • If the cache: 'no-store' option is used.

4. Example Usage:

   fetch('<https://example.com/api/data',> {
     method: 'POST',
     headers: {
       'Content-Type': 'application/json',
       next: { revalidate: 0 } // Prevents caching
     },
     body: JSON.stringify({ key: 'value' })
   });
   

5. Relevant Documentation:

   • For more detailed information, you can refer to the Next.js documentation on fetch options (https://nextjs.org/docs/app/api-reference/functions/fetch#optionsnextrevalidate).
   • Additional context can be found in the GitHub issue discussing POST request caching (https://github.com/vercel/next.js/issues/52405).

By setting revalidate: 0 or cache: 'no-store', you can ensure that your POST requests are not cached, providing you with fresh data on every request.

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon:

@past wave kapa.ai is still learning and improving, please let us know how it did by reacting below

[waxen tundra]

Let me check the knowledge base for you. One moment! :books: