ngx-rxmq

Angular 6 wrapper for Rxmq.js - in-memory message bus based on reactive extensions.

Rxmq.js docs

Rxmq.js

Docs Rxmq.js

Install

Npm:

npm install ngx-rxmq rxmq --save

Yarn:

yarn add ngx-rxmq rxmq

Description

Package provides RxmqService that is a wrapper for Rxmq message broker. RxmqService provides channel, registerChannelPlugin and registerPlugin methods which corresponds with Rxmq methods and requestResponseChannel which return RequestResponseChannel.

ngx-rxmq provide a MQable interface.

interface MQable {
  connect(mq: RxmqService): void;
}

It should be used in service provided as arguments for forRoot and forFeature static methods of NgxRxmqModule. On provided service connect method will be called with RxmqService as argument. Instances of this services will be created at start up of application (forRoot) or on load of a feature module (forFeature).

Usage

Basic usage

Import NgxRxmqModule.forRoot() in AppModule. For feature modules (lazy loaded) import per module NgxRxmqModule.forFeature()

In component - use of Channel:

export class DemoAComponent implements OnInit {

  message$: Observable<string>;

  constructor(private mq: RxmqService) { }

  ngOnInit() {
    this.message$ = this.mq.channel<{message: string}>('demo-a').observe('add.element')
      .pipe(map(event => event.message));
  }

  emitA() {
    this.mq.channel<{message: string}>('demo-a').subject('add.element').next({message: 'Added element to demo-a'});
  }
}

Usege with services

Import NgxRxmqModule in AppModule:

@NgModule({
  imports: [
    ...
    NgxRxmqModule.forRoot([DemoAService, DemoBService]),
    ...
  ],
  providers: [
    DemoAService,
    DemoBService
  ],
  bootstrap: [AppComponent]
})
export class AppModule { }

Services:

@Injectable({
  providedIn: 'root'
})
export class DemoAService implements MQable {

  constructor(private mq: RxmqService) { }

  connect(mq: RxmqService): void {
    mq.channel<{message: string}>('demo-a').observe('add.element')
      .subscribe((event) => {
        console.log('demo-a:add.element', event);
      });
  }

  emit() {
    this.mq.channel<{message: string}>('demo-b').subject('add.element').next({message: 'added element to demo-b'});
  }
}

@Injectable({
  providedIn: 'root'
})
export class DemoBService implements MQable {

  constructor() { }

  connect(mq: RxmqService): void {
    mq.channel<{message: string}>('demo-b').observe('add.element')
      .subscribe((event) => {
        console.log('demo-b:add.element', event);
      });
  }
}

Service DemoAService and DemoBService will be created at startup of application. There is not need to inject this services to component if this services only listen to message queue and act base on event passed to queue eg. side effects, http requests.

For feature modules:

@NgModule({
  imports: [
    ...
    NgxRxmqModule.forFeature([FeatureAService]),
    ...
  ],
  declarations: [FeatureAComponent]
})
export class FeatureAModule { }

Feature service:

@Injectable({
  providedIn: 'root'
})
export class FeatureAService implements MQable {

  constructor() { }

  connect(mq: RxmqService) {
    console.log('FeatureAService.connect', mq);
    mq.channel('demo-a').observe('add.element')
      .subscribe((event) => {
        console.log('Feature A service: demo-a:add.element', event);
      });
  }

}

Feature component:

@Component({
  selector: 'app-feature-a',
  templateUrl: './feature-a.component.html',
  styleUrls: ['./feature-a.component.css']
})
export class FeatureAComponent implements OnInit {

  public readonly form: FormGroup;
  private readonly demoAChanel: Channel<{message: string}>;
  private readonly demoBChanel: Channel<{message: string}>;

  constructor(private formBuilder: FormBuilder, private mq: RxmqService) {
    this.form = formBuilder.group({
      messageDemoA: [''],
      messageDemoB: [''],
    });

    this.demoAChanel = this.mq.channel('demo-a');
    this.demoBChanel = this.mq.channel('demo-b');
  }

  ngOnInit() {
    this.demoAChanel.observe('add.element')
      .pipe(
        map(e => e.message),
        filter((message) => {
          return this.form.get('messageDemoA').value !== message;
        })
      )
      .subscribe((message) => {
        this.form.patchValue({
          messageDemoA: message
        });
      });
  }

  sendDemoA() {
    this.demoAChanel.subject('add.element').next({message: this.form.get('messageDemoA').value});
  }

  sendDemoB() {
    this.demoBChanel.subject('add.element').next({message: this.form.get('messageDemoB').value});
  }
}

Contributors

Daniel Dereziński

Licence

MIT