Introduction to Caching requests with Redis in Node.js.

Posted By :Anubhav Garg |25th August 2019

What is Redis?

Redis is an remote dictionary server, an open-source (BSD licensed), in-memory data structure store, used as a database, cache, and message broker.

 

What is Caching?

Caching is the process of storing data into a software or hardware component so that future requests for that data can be served faster.

 

Install Redis on your machine

sudo apt update

sudo apt install redis-server

sudo systemctl status redis

 

Create a new Directory & generate package.json file

npm init

 

we will use the following npm package in this project:

Express - for routing.

Node fetch - To make http request.

Redis - as node.js redis client.

nodemon  - to setup &  restart the server

 

Now that you have redis installed, add the following code to the index.js file.

 

var express = require('express')
var fetch = require("node-fetch");
var redis = require('redis')
 
var app = express()
 

var client = redis.createClient(6859)
 
client.on('error', (err) => {
    console.log("Error " + err)
});
 
// get the list of photos
app.get('/photos', (req, res) => {
 
    var photosRedisKey = 'user:photos';
 
    // Firstly fetch the data from Redis in case we have it cached in redis
    return client.get(photosRedisKey, (err, photos) => {
 
        // If that data exists in Redis
        if (photos) {
 
            return res.json({ source: 'cache', data: JSON.parse(photos) })
 
        } else { 
 
            // Now Fetch data directly from remote server api
            fetch('https://jsonplaceholder.typicode.com/photos')
                .then(response => response.json())
                .then(photos => {
 
                    // Now Save the API response in Redis store,  api server data automatically expire in 3600 seconds
                    client.setex(photosRedisKey, 3600, JSON.stringify(photos))
 
                    // Send JSON response to client browser
                    return res.json({ source: 'api', data: photos })
 
                })
                .catch(error => {
                    // log error message
                    console.log(error)
                    return res.json(error.toString())
                })
        }
    });
});
 
// Assign express port at 3000 
app.listen(3000, () => {
    console.log('Server listening on port: ', 3000)
});

 

Goto postman and hit URL http://localhost:3000/photos and see the response time:

 

First Request : 

 

Second Request:

 

The first request took 41ms and the second request took 30ms.

 

Conclusion

Redis is a very powerful in-memory data-store tool that we can use in our applications to cache data for upcoming requests. It’s very simple to save and get data without much overhead. 

 

 


About Author

Anubhav Garg

He is an Intellective Web Application Developer. He is good in NodeJs, Angular & MongoDb with knowledge in AWS. He is always motivated to learn new things.

Request For Proposal

Sending message..

Ready to innovate ? Let's get in touch

Chat With Us