How to make "defineCachedFunction" cache the return data forever?

[fandyajpo]

i mean how to make it cached forever?

export const cachedMongoConnection = defineCachedFunction(
  async (name: string) => {
    return await connect("");
  },
  {
    name: "mongoConnection",
    getKey: (name: string) => "name",
  }
);

[fandyajpo]

i have try to add maxAge = Infinity, remove maxAge, remove all key

it doesnt cache the data forever

[stafyniaksacha]

Hi!

Are you trying to cache the mongodb connexion itself? You won't be able to do so because it's not serializable (nitro uses https://github.com/unjs/unstorage under the hood to store cached data).

Instead, you should use something like:

// server/utils/mongodb/client.ts
let cachedMongoConnection;
export async function getMongoConnection() {
  if (!cachedMongoConnection) {
    cachedMongoConnection = await connect("");
  }
  return cachedMongoConnection;
}

Then you can use it like:

// server/utils/mongodb/my-entity.ts
import { getMongoConnection } from './client'

export const cachedMongoEntity = defineCachedFunction(
  async (name: string) => {
    const client = await getMongoConnection()
    const db = client.db('my-db');
    const collection = db.collection('my-entity');

    return await collection.find({}).toArray(); // return serializable data
  }, {
    maxAge: 31536000, // one year
    name: 'mongoEntity',
    getKey: (name: string) => name
  },
)

As per your question for returning same data "forever", nitro tries to follow IETF standards in which one year is advised as a standard max value. See RFC 2616

Hope this helps!

[fandyajpo]

Hey mate, thanks for answering this discussion. Honestly, your response helped me, and I really appreciate it. Plus, your explanation was easy for me to understand.