Wrap function doesnt lookup in cache

[manuarzave]

Hi, im trying to get a list of users, but the .wrap() function always fire the getUsers method and hit the database. this is my code

const cacheManager = require('cache-manager');

const isCacheableValue = (value) => value !== null && value !== false && value !== undefined;

const memoryCache = cacheManager.caching({ store: 'memory', max: 100, ttl: 60 }); // ttl=60 seconds

const multiCache = cacheManager.multiCaching( [memoryCache], { isCacheableValue }, );

function getWrapUsers(req, res) { const cacheKey = req.body.rol; multiCache.wrap(cacheKey, getUsers(req, res), (err, data) => { console.log(RETURN FROM DATABASE ${cacheKey}, err, data); multiCache.wrap(cacheKey, getUsers(req, res), (err2, data2) => console.log(RETURN FROM CACHE ${cacheKey}, err2, data2)); }); }

router.post('/api/getUser', [validateFields], (req, res) => { getWrapUsers(req, res); });

[BryanDonovan]

Hi,

I think you might need to add a console.log statement inside your getUsers function to see if it's really getting called every time.

[manuarzave]

hi, thanks for the repply, i added that console.log, and also debbug it, and it is enter twice in the getUsers()

[BryanDonovan]

Does this code work for you?

const cacheManager = require('cache-manager');
const memoryCache = cacheManager.caching({store: 'memory', max: 100, ttl: 10});

function getUsersFromDb(key, cb) {
    setTimeout(() => {
        console.log("Fetching users from slow database.");
        cb(null, [{id: 123, name: 'Bob'}, {id: 999, name: 'AnotherUser'}]);
    }, 100);
}

function getWrappedUsers(key, cb) {
    multiCache.wrap(key, innerCb => {
        getUsersFromDb(key, innerCb);
    }, (err, users) => {
        cb(err, users);
    });
}

const key = '123456';
const isCacheableValue = value => value !== null && value !== false && value !== undefined;

const multiCache = cacheManager.multiCaching(
    [memoryCache], {isCacheableValue}
);

getWrappedUsers(key, (err, users) => {
    console.log(users);

    getWrappedUsers(key, (err, users) => {
        console.log("This should come from cache");
        console.log(users);
        process.exit();
    });
});

It should print:

Fetching users from slow database.
[ { id: 123, name: 'Bob' }, { id: 999, name: 'AnotherUser' } ]
This should come from cache
[ { id: 123, name: 'Bob' }, { id: 999, name: 'AnotherUser' } ]

[manuarzave]

thanks, it is working, i will try to acomplish this with my original algorithm

[nicosebey]

Hi bryan im @manuarzave partner. As he mention we try your example and worked but if we try to adapt it to make a request to our controller it entered the first time and in the second try it get freezed. here is our code. Could you realize why this is happening?

import {login} from controller/login;

function getWrappedUsers(key, cb, req, res) {
    multiCache.wrap(key, () => {
        login(req, res);
    }, (err, users) => {
        cb(err, users);
    });
}

const key = '123456';

router.post('/api/auth/login', [
    check('username', 'El nombre de usuario es obligatorio').not().isEmpty(),
    check('password', 'La contraseña es obligatoria').not().isEmpty(),
    validateFields,
], (req, res) => {
    getWrappedUsers(key, () => {
        getWrappedUsers(key, () => {
            console.log('This should come from cache');
            process.exit();
        }, req, res);
    }, req, res);
});

[BryanDonovan]

I think you need a callback for the wrap function:

function getWrappedUsers(key, cb, req, res) {
    multiCache.wrap(key, wrapCallback => {
        login(req, res, wrapCallback);
    }, (err, users) => {
        cb(err, users);
    });
}

Does your login function take a callback?

[nicosebey]

Hi bryan you were right, my problem was the missing callback in my login function. Now it is working correctly. Thanks for all.

[BryanDonovan]

No problem!