Giter Club home page Giter Club logo

nestjs-transport-eventbus's Introduction

CI CD Greenkeeper badge Scrutinizer Code Quality codecov npm

Description

The nestjs-transport-eventbus module for Nest.
nestjs-transport-eventbus allows broadcasting events via variety of nestjs trasports in easy way

Installation

npm i nestjs-transport-eventbus

Quick Start

Import TransportEventBusModule into a willing module, example below:

import { TransportEventBusModule } from 'nestjs-transport-eventbus';

@Module({
    imports: [
        TransportEventBusModule
    ],
    controllers: [AppController],
    providers: [
        AppService
    ],
})
export class AppModule {
}

TransportEventBusModule applies two arguments:
publishers - array of transport publishers which are based on ClientProxy
providers - the additional providers for module

Example with RabbitMQ(RabbitPublisher)

For creating a transport publisher there is enough to implement the following steps:

  1. Implement RabbitPublisher, example below:\
import { Injectable } from '@nestjs/common';
import { ClientProxy, Transport, Client} from '@nestjs/microservices';
import { Publisher } from 'nestjs-transport-eventbus';

@Injectable()
@Publisher(Transport.RMQ)//Choose the appropriate type of transport in this case `RMQ`
export class RabbitPublisher {
   @Client({
        transport: Transport.RMQ,
        options: {
            urls: ['amqp://rabbit:rabbit@rabbitmq:5672'],
            queue: 'event_service_queue',
            queueOptions: {
                durable: true,
            },
        },
    })
    client: ClientProxy;
}
  1. Inject RabbitPublisher into TransportEventBusModule, example below:
import { Module } from '@nestjs/common';
import { TransportEventBusModule } from 'nestjs-transport-eventbus';
import { RabbitPublisher } from '...';

@Module({
    imports: [
        TransportEventBusModule.forRoot({
            publishers: [RabbitPublisher]
        })
    ],
    controllers: [],
    providers: [

    ],
})
export class AppModule {
}
  1. Create an event for publisher, example below:
import { TransportType, ExcludeDef } from 'nestjs-transport-eventbus';
import { Transport } from '@nestjs/microservices';

@TransportType(Transport.RMQ)
export class RabbitEvent {
    constructor(
        readonly message: string
    ) {
    }
}

Notice: By default, events are handling on both sides broadcasting server and receiving server, for changing this situation add @ExcludeDef() declaration, can look like below:
....
@TransportType(Transport.RMQ)
@ExcludeDef()
export class RabbitEvent
...

4.Inject TRANSPORT_EVENT_BUS_SERVICE, example below:

import { Inject, Injectable } from '@nestjs/common';
import { TRANSPORT_EVENT_BUS_SERVICE } from 'nestjs-transport-eventbus';
import { IEventBus } from '@nestjs/cqrs';
import { DefaultEvent } from '...';
import { RabbitEvent } from '...'
@Injectable()
export class AppService {
  constructor(
      @Inject(TRANSPORT_EVENT_BUS_SERVICE) private readonly eventBus: IEventBus
  ){

  }
  rabbitEvent(): void {
    this.eventBus.publish(new RabbitEvent('Pass some param'));
  }
}

Notice: Events via AggregateRoot

import { CommandHandler, EventPublisher, ICommandHandler } from '@nestjs/cqrs';
import { TryAggregateRootCommand } from '...';
import { Inject } from '@nestjs/common';
import { TRANSPORT_EVENT_BUS_PUBLISHER } from 'nestjs-transport-eventbus';
import { TestModel } from '...';

@CommandHandler(TryAggregateRootCommand)
export class TryAggregateRootCommandHandler implements ICommandHandler<TryAggregateRootCommand> {
    constructor(
        @Inject(TRANSPORT_EVENT_BUS_PUBLISHER) private readonly publisher: EventPublisher
    ) {
    }

    async execute(command: TryAggregateRootCommand) {
        const {message} = command;
        const aggregator = this.publisher.mergeObjectContext(
            new TestModel()
        );
        aggregator.applyEvent(message);
        aggregator.commit();
    }
}
  1. For handling the broadcasted event on receiving side can look like the following:
import { Controller, Inject } from '@nestjs/common';
import { EventPattern } from '@nestjs/microservices';
import { TRANSPORT_EVENT_BUS_PATTERN, TRANSPORT_EVENT_BUS_SERVICE, TransportEvent } from 'nestjs-transport-eventbus';
import { IEvent, IEventBus } from '@nestjs/cqrs';

@Controller()
export class AppService {

  constructor(
      @Inject(TRANSPORT_EVENT_BUS_SERVICE) private readonly eventBus: IEventBus
  ){

  }
  @EventPattern(TRANSPORT_EVENT_BUS_PATTERN)
  handle(@TransportEvent() event: IEvent): void {
    this.eventBus.publish(event);
  }

Notice: TRANSPORT_EVENT_BUS_PATTERN- can pass via .env

Examples

Example is presented two services which communicate each other via RabbitMQ

nestjs-transport-eventbus's People

Contributors

greenkeeper[bot] avatar sergey-telpuk avatar tsergey-itrex avatar

Stargazers

 avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar  avatar

Watchers

 avatar  avatar  avatar

nestjs-transport-eventbus's Issues

Recommend Projects

  • React photo React

    A declarative, efficient, and flexible JavaScript library for building user interfaces.

  • Vue.js photo Vue.js

    ๐Ÿ–– Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.

  • Typescript photo Typescript

    TypeScript is a superset of JavaScript that compiles to clean JavaScript output.

  • TensorFlow photo TensorFlow

    An Open Source Machine Learning Framework for Everyone

  • Django photo Django

    The Web framework for perfectionists with deadlines.

  • D3 photo D3

    Bring data to life with SVG, Canvas and HTML. ๐Ÿ“Š๐Ÿ“ˆ๐ŸŽ‰

Recommend Topics

  • javascript

    JavaScript (JS) is a lightweight interpreted programming language with first-class functions.

  • web

    Some thing interesting about web. New door for the world.

  • server

    A server is a program made to process requests and deliver data to clients.

  • Machine learning

    Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.

  • Game

    Some thing interesting about game, make everyone happy.

Recommend Org

  • Facebook photo Facebook

    We are working to build community through open source technology. NB: members must have two-factor auth.

  • Microsoft photo Microsoft

    Open source projects and samples from Microsoft.

  • Google photo Google

    Google โค๏ธ Open Source for everyone.

  • D3 photo D3

    Data-Driven Documents codes.