enhancement: async requestInterceptor

[Discountrobot]

The following code snippet will introduce a race condition, should one try to call SomeRESTClient before the _session has been populated, by the createSession request.

@Injectable()
@BaseUrl('https://api.someplace.com')
@DefaultHeaders({
  'Accept': 'application/json',
  'Content-Type': 'application/json'
})
export class SomeRESTClient extends RESTClient {

  private _session: any

  constructor(private _http: Http) {
    super(_http)
    this.setup()
  }

  protected requestInterceptor(req: Request) {
    if (this._session) {
      req.headers.append('Token', this._session.token)
    }
  }

  @POST('/sessions')
  @Produces(MediaType.JSON)
  private createSession( @Body data ): Observable<any> { return null }

  private setup () {
    let api_key = 'xxxx'
    this.createSession({ api_key }).subscribe(session => this._session = session)
  }
}

We should add the possibility to have the requestInterceptor return a promise or similar.

[Paldom]

Could you please give a small example (or simply extend the one above), how would you use the promise if requestInterceptor has support for that?

[zhakhalov]

Hello +1 to feature

Async interceptor could be important for OAuth process, which can has temporary token, needed to update before sending request

Could you also pass Response to responseInterceptor instead of Observable

Here is small example of async interceptor.

@Injectable()
@BaseUrl('https://api.someplace.com')
@DefaultHeaders({
  'Accept': 'application/json',
  'Content-Type': 'application/json'
})
export class SomeRESTClient extends RESTClient {

  constructor(
    @Inject(Http) http: Http
    @Inject(AuthService) private auth: AuthService
  ) {
    super(http)
    this.setup()
  }

  protected requestInterceptor(req: Request): Promise<void> {
    return this.auth
      .token(token => {
        req.headers.append('Autorization', `Bearer ${token}`)
      })
  }

  protected responseInterceptor(res: Response): Promise<void> {
    // do some stuff with raw response
  }
}