Redis client

Forked from https://github.com/camarojs/redis

Features

Redis client which supports resp3.

• Resp3 support
• All command return promises
• Support for ES6 types, such as Map and Set
• TLS support
• Client-side caching
• No dependencies

Quick Start

Install

npm i -save @hverlin/redis

More details: See https://github.com/hverlin/redis/packages/1570132

Usage

// If you want to use resp2 ,change `ClientV3` to `ClientV2`.
const { ClientV3: Client } = require('@hverlin/redis');
const client = new Client();

await client.SET('foo', 'bar');
const response = await client.GET('foo');
console.log(response); // 'bar'

await client.QUIT();

API Reference

Client Options

Here are the list of options (with their default values) that you can pass to the constructor.

const client = new Client({
  host: '127.0.0.1', // IP address of the redis server
  port: 6379, // Port of the redis server
  username: 'default', // username
  password: undefined, // Password
  db: 0, // Redis database to use (see https://redis.io/commands/select/)
  reconnection: true, // Whether to reconnect when an error occurs
  logger: undefined, // callback function to log commands (e.g. console.log)
  tls: undefined, // Object passed as options to [tls.connect()](https://nodejs.org/api/tls.html#tls_tls_connect_options_callback)
});

Commands

Redis commands can be used like this:

const client = new Client();

// https://redis.io/commands/set/
await client.SET('mykey', 'Hello');
await client.SET('anotherkey', 'will expire in a minute', 'EX', 60);

// https://redis.io/commands/get/
await client.GET('mykey'); // "Hello"

// https://redis.io/commands/hset/
await client.HSET('myhash', 'field1', 'Hello');

// https://redis.io/commands/hget/
await client.HGET('myhash', 'field1'); // "Hello"

// https://redis.io/commands/hgetall/
await client.HGETALL('myhash'); // "Map(1) { 'field1' => 'Hello' }"
// ... other commands

See the complete list: https://redis.io/commands.

Events

• message: See Pub/Sub
• error: Emitted when an error occurs.
• connect: Emitted when the connection with the Redis server is established. Commands issued before the connect event are queued, and replayed just before this event is emitted.

Pub/Sub

You can receive pub/sub messages by using the .on('message') event handler. If you are using the resp2, you need to create a new client to receive messages.

const client = new Client();

client.SUBSCRIBE('test');
client.on('message', (data) => {
  // data: ['message', 'somechannel', 'this is the message']
  console.log(data);
});

Client-side caching

You can implement Client-side caching on top of this library.

Here is a very simple example which uses a Map to cache results from Redis. Listen for invalidation messages to know when to remove entries from your local cache.

Note that if you use TTL, you would also need to manage them for the local cache as Redis does not send invalidation message when the TTL expires

const { ClientV3: Client } = require('@hverlin/redis');
const client = new Client();

const localCache = new Map();

client.on('message', (args) => {
  const [message, values] = args;
  console.log(message, values);
  if (message === 'invalidate') {
    for (const key of values) {
      localCache.delete(key);
    }
  }
});

await client.CLIENT('tracking', 'on');
// if you prefer to use the Broadcasting mode, use
// https://redis.io/docs/manual/client-side-caching/#broadcasting-mode
// await client.CLIENT('tracking', 'on', 'BCAST');

async function get(key) {
  if (localCache.has(key)) {
    return localCache.get(key);
  }

  const response = await client.GET('foo');
  localCache.set('foo', response);
  return response;
}

await client.SET('foo', 'bar');
console.log(await get('foo')); // from redis server
console.log(await get('foo')); // from local cache

await client.SET('foo', 'baz'); // will trigger an invalidation message
console.log(await get('foo')); // from redis server