在Angular 2应用程序开始使用AoT之前从数据库加载配置

所以我创建了一个ConfigurationService来从后端获取数据,我试图在启动应用程序之前使用根模块中的app_initializer来调用配置服务.我已经设法在几个月前创建的角度应用程序中做了这个(角度RC4),并且这次尝试以同样的方式执行此操作.

app.module.ts – 首先尝试

import { NgModule,APP_INITIALIZER } from '@angular/core';
import { AppComponent } from './app.component';
import { RouterModule } from '@angular/router';
import { HttpModule } from '@angular/http';   

import { ConfigurationService } from "./shared/services/configuration.service";

@NgModule({
    imports: [
        ...
    ],declarations: [
        ...   
    ],providers: [
        {
            provide: APP_INITIALIZER,useFactory: (config: ConfigurationService) => () => config.loadConfiguration(),deps: [ConfigurationService]
        },ConfigurationService        
    ],bootstrap: [AppComponent]
})

export class AppModule { }

这导致以下错误：

Error encountered resolving symbol values statically. Function calls are not supported. Consider replacing the function or lambda with a reference to an exported function

我认为这与我正在使用的AoT编译器有关.我用工厂替换了lambda表达式.

app.module.ts – 第二次尝试

import { NgModule,APP_INITIALIZER } from '@angular/core';
import { AppComponent } from './app.component';
import { RouterModule } from '@angular/router';
import { HttpModule } from '@angular/http';   

import { ConfigurationService } from "./shared/services/configuration.service";
import { ConfigurationServiceFactory } from "./shared/services/configuration.service.factory";

@NgModule({
    imports: [
        ...
    ],useFactory: ConfigurationServiceFactory,bootstrap: [AppComponent]
})

export class AppModule { }

configuration.service.factory.ts

import { ConfigurationService } from "./configuration.service";

export function ConfigurationServiceFactory(configurationService: ConfigurationService) {  
    return configurationService.loadConfiguration()
        .then(currentUser => {
                configurationService.currentUser = currentUser;                
            }
        );    
}

这实际上是使用配置服务从后端获取数据,但是在启动应用程序之前不等待承诺解析.当用户在主页(可供所有人访问)启动时,它可以工作,然后导航到受非管理员用户限制的组件.但是当用户刷新受限制的页面时,OnInit(我确定用户是否具有访问权限)会在加载配置之前触发.在我的情况下,导致用户被拒绝访问他们应该访问的页面.

configuration.service.ts

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

import { CurrentUser } from "../models/currentuser.model";

@Injectable()
export class ConfigurationService {
    public apiUrl: string = "api/";
    public currentUser: CurrentUser;

    constructor(private http:Http) {}

    /**
    * Get configuration from database
    */
    public loadConfiguration(): Promise<CurrentUser> {
        return this.http.get(this.apiUrl + "application/GetDataForCurrentUser")
            .toPromise()
            .then(this.extractData)
            .catch(this.handleError);
    }       
}

组件实现

import { Component,OnInit } from '@angular/core';
import { MessageService } from '../shared/message/message.service'
import { ConfigurationService } from "../shared/services/configuration.service";

@Component({    
    selector: 'simple',templateUrl: 'simple.component.html'
})
export class SimpleComponent implements OnInit{ 
    constructor(private messageService: MessageService,private configurationService: ConfigurationService) {

    }
    ngOnInit() {                      
        if (!this.configurationService.isAdmin()) {            
            this.messageService.addMessage("Access denied","danger");
        }
    }
}

我现在全都没有想法了,我找了一个解决方案,但只是找到了推荐lambda选项的人,这对我不起作用.