Controller Inheritance support

[jselesan]

Hi there! It would be nice to support controller inheritance, which can allow create (for example) a CrudController with CRUD methods for a REST API, calling a service to fetch data, and then inherit from that controller for each specific entity type

[MichalLytek]

Prefer composition over inheritance - put your CRUD methods logic into generic services and inject it to the controller.

[jselesan]

Yes @19majkel94, is what I'm doing, but I have to repeat the route handlers on every controller. Not a big deal, but a lot of repeated code.

[ssljivic]

Good point @jselesan

[MichalLytek]

CrudController with CRUD methods for a REST API, calling a service to fetch data, and then inherit from that controller for each specific entity type
I have to repeat the route handlers

So you want something like a generic controller? Or can you show me your current use case and how this feature should looks&works 😉

[jselesan]

I think something like this (may not compile ;))

export abstract class CrudController {
  private _service: CrudService;
  protected setService(service: CrudService) {
    this._service = service;
  }

 @Get("/")
 all() {
   return this.service.getAll();
 }  
 
 /* the other methods are similar */
}

@JsonController("/employees")
export class EmployeesController extends CrudController {
  constructor(private service: EmployeesService) { //EmployeesService should extend CrudService
    this.setService(service);
  }
}

This way, EmployeesController will expose all() method, that can be match to a GET / request

I'm not sure if it is possible, is just an idea :)

[pleerock]

@jselesan code you provided does not look good even if it was implementable. In my experience inheritance in controllers never bring somethings really valuable, its only makes things complex and unpredictable. Controllers should be simple as hell and if you have duplication in logic - simply extract this logic into services - thats correct places for such logic. If you have duplication in decorators and routes - thats not an issue, having duplicated route decorators just makes things more explicit. Really really no need to make things complex (and make life harder for everyone except you) with such patterns.

[MichalLytek]

If you have duplication in decorators and routes - thats not an issue, having duplicated route decorators just makes things more explicit.

+1000 😉

I also have something like @Get("/") all() { return this.service.getAll(); }
in almost every controller but it's not a big deal if you have repeated logic extracted into services.

@jselesan
Imagine that you use the extending pattern to reduce boilerplate. So in some time you can get the inheritance chain that consist of 10 extending controllers and there are difference for every controller. So instead of look into controller mapped to REST API resource path and see what's happening there (like reading a doc) you have to traverse all the way up to see all actions, etc. Good luck with debugging 😉

For easier development I recomend you to create your own template or even snippet for IDE so you can just type the service name and type for import and inject, controller name or path and the base thing will be configured in 30s 😃

[pleerock]

Feel free to continue discussion

[95gabor]

+1