Soundcore Common

This package contains common utilities used in the soundcore api backend

Installation

npm install --save @soundcore/redis ioredis

or using yarn

yarn add @soundcore/redis ioredis

Usage

First, you have to register the module in your app.module.ts:

import { Module } from '@nestjs/common';
import { SoundcoreRedisModule } from '@soundcore/redis';

@Module({
  imports: [
    SoundcoreRedisModule.forRoot({
        // IORedis options go here
    })
  ]
})
export class AppModule {}

To configure the redis client, please read the docs of the ioredis package. After that, you can inject the redis client in your services like that:

import { Injectable } from '@nestjs/common';
import Redis from "ioredis";

@Injectable()
export class AppService {
  constructor(private readonly redis: Redis) {}
}

You can choose between 2 redis connections: One that is just for subscribing, publishing and a default one. To inject just the connection to subscribe to messages, please do the following:

import { Injectable } from '@nestjs/common';
import { RedisSub } from "@soundcore/redis";

@Injectable()
export class AppService {
  constructor(private readonly redis: RedisSub) {}
}

This is done to prevent, that there is only one connection for developers to use. Because of the nature of redis, if a connection goes into subscribtion mode, no messages can be published anymore. If you do not care about Pub/Sub, then stick to the default Redis injection token shown in the first example of this section.

If you need more connections. You can register new connections in your modules using registerConnections().

Subscribe

Redis is known for its ability for Pub/Sub. To make subscribing to messages and channels more comfortable, a new decorator has been introduced: @RedisSubscribe(channel: string, expectJSON: boolean). This is a method decorator and takes in 2 parameters. The first one specifies the channel to which the client should listen. The second parameter defines, wether the client should parse the JSON string to an actual JSON object or not. Please see the following example on how to use the decorator:

import { RedisSubscribe } from "@soundcore/redis";

@RedisSubscribe("test", true)
public handleSubscribe(channel: string, payload: any) {
  console.log(channel, payload);
}

The example above would subscribe on the channel called "test" and parse the received messages to an JSON object. Please make sure that on these channels, only json strings are sent. Otherwise it would cause parsing errors and the payload object may become a nullish value.