Nest-STOMP

Description

A STOMP module for Nest.js.

Installation

$ npm install @gauravgango/nestjs-stomp --save

Usage

Import

Nest-mqtt will register as a global module.

You can import with configuration

// app.module.ts
import { Module } from '@nestjs/common';
import { StompModule } from '@gauravgango/nestjs-stomp';

@Module({
  imports: [StompModule.forRoot(options)]
})
export class AppModule {}

or use async import method

// app.module.ts
import { Module } from '@nestjs/common';
import { StompModule } from '@gauravgango/nestjs-stomp';

@Module({
  imports: [StompModule.forRootAsync({
    useFactory: () => options,
  })]
})
export class AppModule {}

// app.module.ts
import { Module } from '@nestjs/common';
import { StompModule } from '@gauravgango/nestjs-stomp';

@Module({
  imports: [MqttModule.forRootAsync({
    useClass: ServiceName,
  })]
})
export class AppModule {}

Subscribe

You can define any subscriber or consumer in any provider. For example,

import { Injectable } from '@nestjs/common';
import { Subscribe, Payload, Topic } from 'nest-mqtt';

@Injectable()
export class TestService {
  @Subscribe('queue/name')
  test() {
  
  }
  
  @Subscribe({
    queue: 'queue/name',
    headers: {customHeader: 'CustomHeaderValue'}
  })
  test2() {
    
  }
}

Also, you can inject parameter with decorator:

import { Injectable } from '@nestjs/common';
import { Subscribe, Payload } from 'nest-mqtt';

@Injectable()
export class TestService {
  @Subscribe('test')
  test(@Payload() payload) {
    console.log(payload);
  }
}

Here are all supported parameter decorators:

Payload(transform?: AvailableStompTransforms)

Get the payload data of incoming message. You can pass in a transform function for converting. The default value will be an object containing body and binaryBody properties of message.

   @Subscribe('queuename')
   queueHandler(
     @Payload('json') content: SomeInterface
   ) {
     //... the content will be parsed automatically using the JSON.parse on body of message
   }
   

Look at AvailableStompTransforms type for details in library

Headers

Get the header date of incoming message.

   @Subscribe('queuename')
   queueHandler(
     @Headers() headers: StompHEaders
   ) {
     //... will return the headers sent in message
   }
   

NackAction

Get the header date of incoming message.

   @Subscribe('queuename')
   queueHandler(
     @NackAction() nackAction: (headers?: StompHeaders) => void
   ) {
    nackAction({someHeader: 'Value of header'})
     //... nack action in the message.
   }
   

AckAction

Get the header date of incoming message.

   @Subscribe('queuename')
   queueHandler(
     @AckAction() ackAction: (headers?: StompHeaders) => void
   ) {
    ackAction({someHeader: 'Value of header'})
     //... ack action in the message.
    //
   }
   

Points To Note:

• The default behaviour is to auto acknowledge using ack and nack on any failure. In order to change the behaviour set autoNack and autoAck in Subscribe decorator along with NackAction and AckAction parameter decorators to control the message flow.
• Default subscription header are
  • ack equals to client

Publish

Nest-mqtt wrap some functions with Promise and provide a provider.

import { Inject, Injectable } from '@nestjs/common';
import { StompService } from '@gauravgango/nestjs-stomp';

@Injectable()
export class TestService {
  constructor(
    private stompService: StompService
  ) {}

  async testPublish() {
    this.stompService.publishJson('topic', {
      foo: 'bar'
    });
  }

}

License

MIT licensed.