DI with cyclic dependency with custom HTTP and ConfigService
I'm trying to implement a ConfigService to retrieve the right configuration for the right environment in the project. I'm currently encountering a cyclic dependancy
(index):28 Error: (SystemJS) Provider parse errors:
Cannot instantiate cyclic dependency! Http: in NgModule AppModule
Error: Provider parse errors:
I've explored the code and there is the problem, in my opinion:
CustomHttp
constructor(backend: XHRBackend, options: RequestOptions, public spinnerService: SpinnerService, public exceptionService: ExceptionService, public configService: ConfigService)
ExceptionService
constructor(private _notificationService: NotificationService, private _spinnerService: SpinnerService, private _configService: ConfigService, private _router: Router)
ConfigService
constructor(private http: Http) {}
As you can see, I've a cyclic dependancies illustrated in this diagram (without any good convention):
My question now is, how to fix it? I've heard of Injector
but I'm not sure I can really use it in this context.
Thanks in advance for your answer.
DI can't resolve cyclic dependencies. A workaround is to inject the injector and acquire the instance imperatively:
@Injectable()
class ConfigService {
private http: Http;
constructor(injector:Injector) {
setTimeout(() => this.http = injector.get(Http);
}
}