See how Observable.flatMap makes the world a better place to code! compare this with https://gist.github.com/paritosh64ce/917e70f43e7d160a27b00f36491b87c0

myHttpSvc.ts

import { Http, Headers, RequestOptions } from '@angular/http';
import { Observable } from 'rxjs/Observable';

@Injectable()
export class myHTTPSvc {
  constructor(private http: Http, private upSvc: MyUserProfileService) {}

  get(url) : Observable<any> {
    this.upSvc.getLoggedInUserDetails()
      .flatMap(details => {
        let headerConfig = this.getHeaderConfig(details);
        return this.http.get(url, headerConfig)
          .map(data => data.json());
      });
  }
  
  private getHeaderConfig(loggedInUserDetails: any): RequestOptions {
    let options = new RequestOptions();
    options.headers = new Headers();
    options.headers.append('license', loggedInUserDetails.licenseInfo);
    // or any details you want to push in message header
    return options;
  }