Typescript 从服务器获取同步数据

Question

我的方法中的控制流有问题。如何等待来自服务器的数据？是否可以在服务的构造函数中准备数据，并在注入后在所有组件中单例获取？

import { Permission } from '../_models/Permission';
import { Injectable, OnInit } from "@angular/core";
import { AuthService, AppHttpService } from '../_services/index';
import { RequestActionType } from '../_models/RequestActionType';


@Injectable()
export class PermissionService {

    private getUrl: string = "/Permission/GetAllPermissions";
    private permissions: Permission[] = [];

    constructor(private httpService: AppHttpService, private authService: AuthService) {

        this.PreparePermissionData();
    }

    public PreparePermissionData() {
        if (this.authService.loggedIn()) {
            this.httpService.authGet(this.getUrl).then(response => {
                this.permissions = response.Data as Permission[];
            });
        }

Answer 1

import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import {Observable} from 'rxjs/Observable'

 export class MyService {
   private getUrl:string = "/Data/GetData"
   constructor(private http: Http) { }

   public DoSomething(){
     let myData = [];

     this.http.get(this.getUrl).map(res => res.json()).subscribe(data => {
        this.somethingWithData(data)
     });

  } 
  public somethingWithData(data) {
    //do anything here with data
  }
}

Answer 2

是否可以在服务的构造函数中准备数据，并在注入后在所有组件中以单例形式获取数据？