Setting services

Singleton services for easy data manipulation

Overview

Service is a singleton class instance which able to be used by any class using injection.

Defining class as a service

For setting class as a service the class must be decorated with the @Injectable() decorator, this will set the class as singleton.

@Injectable()
class MyService{
    public listeners:number = 0;

    public incListeners(){
        this.listeners++;
    }

    public decListeners(){
        this.listeners--;
    }
}

The service need to be set on the module services array:

@ServerModule({
    services: [MyService]
})
export class MyModule{
    constructor(){}
}

later we will be able to inject the service instance.

Variable binding - Injection

• @Inject(MyService) private myService:MyService

• @Inject("MyService") private myService:MyService

• constructor(private myService:MyService)

Retrieve value from the "container"

The InversifyJS container is handling and storing singleton objects. The container is stored on the server instance, each request and the ServerContainerService

Retrieve the container object

We are able to retrieve the singleton class instance using the following methods:

• <HttpServer>server.container

• req.container

• ServerContainerService.getContainerById(serverInstanceId) - Using the HttpServer object instanceId.

Retrieve service instance

After retrieving the container we able to get the service instance as following:

• private myService:MyService = container.get(MyService)

Or

• private myService:MyService = container.get("MyService")