✨ NATS Streaming Server and Client transport modules for NestJS
Library that implements NATS Streaming server(subscriber) and client(publisher) transport using NestJS and his Microservices library.
⭐️ Features
- ClientStan: A class that implements Nest's ClientProxy to emit event to NATS Streaming.
- ServerStan: A class that implements Nest's CustomTransportStrategy to listen to events from NATS Streaming.
📖 Contents
🛠 Installation
npm install nestjs-stan-transport --save
Usage
Importing
For publishing:
app.module.ts
import { Module } from '@nestjs/common';
import { StanTransportModule } from 'nestjs-stan-transport';
@Module({
imports: [
StanTransportModule.forRoot({
url: 'nats://localhost:4222',
group: 'user.workers',
clusterId: 'test-cluster',
clientId: 'user-service-publisher',
})
],
})
export class ApplicationModule {}
For custom transport strategy(subscriber)
main.ts
import {NestFactory} from '@nestjs/core';
import {ServerStan} from "nestjs-stan-transport";
import {AppModule} from './app.module';
async function bootstrap() {
const options = {
strategy: new ServerStan({
url: 'nats://localhost:4222',
group: 'user.workers',
clusterId: 'test-cluster',
clientId: 'user-service',
})
}
const app = await NestFactory.createMicroservice(AppModule, options)
await app.listen(() => logger.log('Microservice is listening'));
}
bootstrap();
For Cluster connection provide a comma-separated URL string:
const options = {
strategy: new ServerStan({
url: 'nats://server1:4222,nats://server2:4222',
group: 'user.workers',
clusterId: 'test-cluster',
clientId: 'user-service',
})
}
Event emitter
For emit events to NATS Streaming inject the ClientStan instance:
import { ClientStan } from "nestjs-stan-transport";
export class UserPublisherService {
constructor(
private readonly client: ClientStan,
) {}
async execute(event: UserCreatedEventModel) {
this.client.emit('UserCreatedEventSubject', event);
}
}
Event Listener
Use @EventPattern annotation if you want to listen a specific event.
import { EventPattern } from '@nestjs/microservices';
export class UserHanlderService {
@EventPattern('UserCreatedEventSubject')
async handleEvent(event: UserCreatedDto) {
this.client.emit('UserCreatedEventSubject', event);
}
}
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