Originally published at: http://www.sitepoint.com/using-redis-node-js/
Redis is a fast and efficient in-memory key-value store. It is also known as a data structure server, as the keys can contain strings, lists, sets, hashes and other data structures. If you are using Node.js, you can use the node_redis
module to interact with Redis. This tutorial explains various ways of interacting with Redis from a Node.js app using the node_redis
library.
Installing node_redis
node_redis
, as you may have guessed, is the Redis client for Node.js. You can install it via npm using the following command.
npm install redis
Getting Started
Once you have installed node_redis
module you are good to go. Let’s create a simple file, app.js
, and see how to connect with Redis from Node.js.
app.js
var redis = require('redis'); var client = redis.createClient(); //creates a new client
By default, redis.createClient()
will use 127.0.0.1
and 6379
as the hostname and port respectively. If you have a different host/port you can supply them as following:
var client = redis.createClient(port, host);
Now, you can perform some action once a connection has been established. Basically, you just need to listen for connect
events as shown below.
client.on('connect', function() { console.log('connected'); });
So, the following snippet goes into app.js
:
var redis = require('redis'); var client = redis.createClient(); client.on('connect', function() { console.log('connected'); });
Now, type node app
in the terminal to run the app. Make sure your Redis server is up and running before running this snippet.
Storing Key-Value Pairs
Now that you know how to connect with Redis from Node.js, let’s see how to store key-value pairs in Redis storage.
Storing Strings
All the Redis commands are exposed as different functions on the client
object. To store a simple string use the following syntax:
client.set('framework', 'AngularJS');
Or
client.set(['framework', 'AngularJS']);
The above snippets store a simple string AngularJS
against the key framework
. You should note that both the snippets do the same thing. The only difference is that the first one passes a variable number of arguments while the later passes an args
array to client.set()
function. You can also pass an optional callback to get a notification when the operation is complete:
client.set('framework', 'AngularJS', function(err, reply) { console.log(reply); });