Introduction to Cache-manager

The cache-manager library is a powerful caching module for Node.js applications, allowing developers to implement various cache strategies seamlessly. In this comprehensive guide, we’ll explore a rich set of APIs provided by cache-manager with practical examples and a full-fledged application demonstrating its usage.

Basic Setup

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

memoryCache.set('foo', 'bar', { ttl: 5 }, (err) => {
  if (err) throw err;
  console.log('cached foo/bar');
});

memoryCache.get('foo', (err, result) => {
  if (err) throw err;
  console.log(result); // bar
});

Multiple Stores

const redisStore = require('cache-manager-redis-store');

const multiCache = cacheManager.multiCaching([memoryCache, cacheManager.caching({
  store: redisStore,
  host: 'localhost', port: 6379, db: 0, ttl: 600
})]);

multiCache.set('foo', 'bar', (err) => {
  if (err) throw err;
  console.log('Value cached in multiple stores');
});

multiCache.get('foo', (err, result) => {
  if (err) throw err;
  console.log(result);
});

API Examples

Setting Cache

memoryCache.set('key1', 'value1', { ttl: 10 }, (err) => {
  if (err) throw err;
});

Getting Cache

memoryCache.get('key1', (err, result) => {
  if (err) throw err;
  console.log(result);
});

Del Cache

memoryCache.del('key1', (err) => {
  if (err) throw err;
});

Wrapping Cache

function fetchData(id, cb) {
  // Simulate fetching data
  setTimeout(() => cb(null, { id, data: 'Sample data' }), 1000);
}

memoryCache.wrap('data-id', (cb) => fetchData(1, cb), { ttl: 30 }, (err, result) => {
  if (err) throw err;
  console.log(result);
});

App Example Using cache-manager

const express = require('express');
const cacheManager = require('cache-manager');
const app = express();
const port = 3000;

const memoryCache = cacheManager.caching({ store: 'memory', max: 100, ttl: 10 /*seconds*/ });

function fetchUser(id) {
  // Simulate database access
  return new Promise((resolve) => setTimeout(() => resolve({ id, name: 'User' + id }), 2000));
}

app.get('/user/:id', async (req, res) => {
  const userId = req.params.id;

  memoryCache.wrap(userId, () => fetchUser(userId), { ttl: 10 })
    .then(result => res.json(result))
    .catch(err => res.status(500).send(err));
});

app.listen(port, () => {
  console.log(`Server running at http://localhost:${port}/`);
});

With these powerful APIs at your disposal, implementing efficient caching in your Node.js applications using cache-manager is a breeze!

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