neshClassicCache

neshClassicCache allows you to cache the results of expensive operations, like database queries, and reuse them across multiple requests. Unlike the neshCache or unstable_cache ↗ function, neshClassicCache must be used in a Next.js Pages Router allowing users to cache data in the getServerSideProps and API routes.

This function is experimental, the API may change in the future. Use with caution.

Parameters

fetchData

This is an asynchronous function that fetches the data you want to cache. It must be a function that returns a Promise.

commonOptions

This is an object that controls how the cache behaves. It can contain the following properties:

• tags - An array of tags to associate with the cached result. Tags are used to revalidate the cache using the revalidateTag and revalidatePath functions.

• revalidate - The revalidation interval in seconds. Must be a positive integer or false to disable revalidation. Defaults to export const revalidate = time; in the current route.

• argumentsSerializer - A function that serializes the arguments passed to the callback function. Use it to create a cache key. Defaults to JSON.stringify(args).

• resultSerializer - A function that serializes the result of the callback function.Defaults to Buffer.from(JSON.stringify(data)).toString('base64').

• resultDeserializer - A function that deserializes the string representation of the result of the callback function. Defaults to JSON.parse(Buffer.from(data, 'base64').toString('utf-8')).

• responseContext - The response context object. If provided, it is used to set the cache headers acoording to the revalidate option. Defaults to undefined.

Returns

neshClassicCache returns a function that when invoked, returns a Promise that resolves to the cached data. If the data is not in the cache, the provided function will be invoked, and its result will be cached and returned. The first argument is the options which can be used to override the common options. In addition, there is a cacheKey option that can be used to provide a custom cache key.

Example

import { neshClassicCache } from '@neshca/cache-handler/functions';
import axios from 'axios';
 
export const config = {
  runtime: 'nodejs',
};
 
async function getViaAxios(url) {
  try {
    return (await axios.get(url.href)).data;
  } catch (_error) {
    return null;
  }
}
 
const cachedAxios = neshClassicCache(getViaAxios);
 
export default async function handler(request, response) {
  if (request.method !== 'GET') {
    return response.status(405).send(null);
  }
 
  const revalidate = 5;
 
  const url = new URL('https://api.example.com/data.json');
 
  // Add tags to be able to revalidate the cache
  const data = await cachedAxios({ revalidate, tags: [url.pathname], responseContext: response }, url);
 
  if (!data) {
    response.status(404).send('Not found');
 
    return;
  }
 
  response.json(data);
}