Connecting to Redis on ioredis (Node.js)

This section describes how to access a Redis instance on ioredis. For more information about how to use other Redis clients, visit the Redis official website.

The following operations are based on an example of accessing a Redis instance on a client on an elastic cloud server (ECS).

The operations described in this section apply only to single-node, master/standby, and Proxy Cluster instances. To access a Redis Cluster instance on ioredis, see Node.js Redis client description.

Prerequisites

A Redis instance is created, and is in the Running state. To create a Redis instance, see Buying a DCS Redis Instance.
An ECS has been created. For details about how to create an ECS, see Purchasing a Custom ECS
If the ECS runs the Linux OS, ensure that the GCC compilation environment has been installed on the ECS.
The client and the Redis instance must be interconnected before connecting to the instance. For details, see Network Conditions for Accessing DCS Redis.

Connecting to Redis on ioredis

For client servers running Ubuntu (Debian series):

View the IP address/domain name and port number of the DCS Redis instance to be accessed.

For details, see Viewing and Modifying Basic Settings of a DCS Instance.
Log in to the ECS.
Install Node.js.
```
apt install nodejs-legacy
```
If the preceding command does not work, run the following commands:
```
wget https://nodejs.org/dist/v0.12.4/node-v0.12.4.tar.gz --no-check-certificate
tar -xvf node-v4.28.5.tar.gz
cd node-v4.28.5
./configure
make
make install
```
After the installation is complete, run the node --version command to query the Node.js version to check whether the installation is successful.
Install the node package manager (npm).
```
apt install npm
```
Install the Redis client ioredis.
```
npm install ioredis
```

Edit the sample script for connecting to a DCS Redis instance.

Add the following content to the ioredisdemo.js script, including information about connection and data reading.

var Redis = require('ioredis');
var redis = new Redis({
  port: 6379,          // Redis port
  host: '192.168.0.196',   // Redis host
  family: 4,           // 4 (IPv4) or 6 (IPv6)
  password: '******',
  db: 0
}); 
redis.set('foo', 'bar');
redis.get('foo', function (err, result) {
  console.log(result);
}); 
// Or using a promise if the last argument isn't a function
redis.get('foo').then(function (result) {
  console.log(result);
});
// Arguments to commands are flattened, so the following are the same:
redis.sadd('set', 1, 3, 5, 7);
redis.sadd('set', [1, 3, 5, 7]);
// All arguments are passed directly to the redis server:
redis.set('key', 100, 'EX', 10);

host indicates the example IP address/domain name of the DCS instance and port indicates the port number of the DCS instance. For details about how to obtain the IP address/domain name and port, see 1. Change them as required. ****** indicates the password used for logging in to the chosen DCS Redis instance. This password is defined during DCS Redis instance creation.

Run the sample script to access the chosen DCS Redis instance.
```
node ioredisdemo.js
```

For client servers running CentOS (Red Hat series):

View the IP address/domain name and port number of the DCS Redis instance to be accessed.

For details, see Viewing and Modifying Basic Settings of a DCS Instance.
Log in to the ECS.
Install Node.js.
```
yum install nodejs
```
If the preceding command does not work, run the following commands:
```
wget https://nodejs.org/dist/v0.12.4/node-v0.12.4.tar.gz --no-check-certificate
tar -xvf node-v0.12.4.tar.gz
cd node-v0.12.4
./configure
make
make install
```
After the installation is complete, run the node --version command to query the Node.js version to check whether the installation is successful.
Install npm.
```
yum install npm
```
Install the Redis client ioredis.
```
npm install ioredis
```

Edit the sample script for connecting to a DCS Redis instance.

Add the following content to the ioredisdemo.js script, including information about connection and data reading.

var Redis = require('ioredis');
var redis = new Redis({
  port: 6379,          // Redis port
  host: '192.168.0.196',   // Redis host
  family: 4,           // 4 (IPv4) or 6 (IPv6)
  password: '******',
  db: 0
});
redis.set('foo', 'bar');
redis.get('foo', function (err, result) {
  console.log(result);
});
// Or using a promise if the last argument isn't a function
redis.get('foo').then(function (result) {
  console.log(result);
}); 
// Arguments to commands are flattened, so the following are the same:
redis.sadd('set', 1, 3, 5, 7);
redis.sadd('set', [1, 3, 5, 7]); 
// All arguments are passed directly to the redis server:
redis.set('key', 100, 'EX', 10);