Ioredis

What is Ioredis?

Ioredis is a Redis client for Node and io.js, that works with Node callbacks and Bluebird promises.

Installing Ioredis

We can install Ioredis through the npm package manager:

npm install ioredis

Basic usage

We will be going through the basic steps to build a program using Ioredis.

• The first step is importing the ioredis library in our server.js file

• const Redis = require('ioredis');
  

• Then we need to create a new Redis' instance, connecting to our Redis server, we should pass the construtor our redis' server IP direction or port

• const redis = new Redis();
  new Redis();       // Connect to 127.0.0.1:6379
  new Redis(6380);   // 127.0.0.1:6380
  new Redis(6379, '192.168.1.1');        // 192.168.1.1:6379
  new Redis('/tmp/redis.sock');
  new Redis({
    port: 6379,          // Redis port
    host: '127.0.0.1',   // Redis host
    family: 4,           // 4 (IPv4) or 6 (IPv6)
    password: 'auth',
    db: 0
  });
  

• Once done that we can start using redis.

Basic operations

We will be going through the basic operations needed for our project.

Get

redis.get('key', callback(err, res));

This function is used to obtain the value associated to a determined key from Redis, it returns the value, or null if the key is not found.

Key

String associated to our desired value.

Callback(err, res)

Function called once the response is received, "res" contains the response and "err" the corresponding error code, if there is any.

Set

redis.set('key', 'value', [parameters])

This function is used to store a value associated to a determined key.

Key

String that will be associated to our value.

Value

Value stored in the Redis database.

Parameters

Additional parameters passed to the redis Database. We will be using the 'ex' parameter.

"EX" parameter

This parameter is used to set an Expiration time for the database's values.

redis.set('key', 'value, 'ex', time);

Time

Seconds before the stored information is automatically removed.