Question

我有以下代码：

// Service
import { Injectable } from '@angular/core';
import { HttpClient, HttpHeaders } from '@angular/common/http';
import { NbAuthService, NbAuthJWTToken } from '@nebular/auth';

interface PlatformInterface {
  id: number;
  name: string;
}

@Injectable()
export class PlatformService {

  data = [];

  constructor(
    private authService: NbAuthService,
    private http: HttpClient) { }

  getData() {
    console.log(this.authService.getToken()); // This is Observable
    return this.http.get<PlatformInterface[]>(
      'http://app-backend.test/app/platforms',
      {
        headers: new HttpHeaders({
          'Content-Type': 'application/json',
          'Authorization': 'Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJodHRwOlwvXC9ldmVyZ2FtZS1iYWNrZW5kLnRlc3RcL2F1dGhcL3NpZ25pbiIsImlhdCI6MTUzODczNDc2MywiZXhwIjoxNTM4ODIxMTYzLCJuYmYiOjE1Mzg3MzQ3NjMsImp0aSI6InR1SnZLQlFHR0RXRmhGcWciLCJzdWIiOjEsInBydiI6Ijg3ZTBhZjFlZjlmZDE1ODEyZmRlYzk3MTUzYTE0ZTBiMDQ3NTQ2YWEifQ.nwf10QpYweuzukerwvzPBqhGMuwGC8o5yCr0zywCa_A'
        })
      }
    );
  }
}

// Component code
this.service.getData().toPromise().then(res => {
  this.source.load(res);
});

我正在尝试获取令牌并使它看起来像"Bearer " + token。

根据Creating Expression Trees by Using the API，NbAuthService返回该令牌的Observable，但我不知道在侦听Observable之后如何返回该值。

我尝试了不同的方法，但无法掌握Observables的概念。

有人可以帮忙吗？

Answer 1

您要先获取AuthToken，然后再进行第二次调用。为此，您可能需要map响应，然后从响应内部返回实际的Observable。但这会给您Observable<Observable<PlatformInterface[]>>，因此您可以使用flatMap

尝试一下：

import { Injectable } from '@angular/core';
import { HttpClient, HttpHeaders } from '@angular/common/http';
import { NbAuthService, NbAuthJWTToken } from '@nebular/auth';
import { flatMap } from 'rxjs/operators';

interface PlatformInterface {
  id: number;
  name: string;
}

@Injectable()
export class PlatformService {

  data = [];

  constructor(
    private authService: NbAuthService,
    private http: HttpClient
  ) {}

  getData() {

    return this.authService.getToken()
      .pipe(flatMap(token => {
        return this.http.get <PlatformInterface[]>(
          'http://app-backend.test/app/platforms', {
            headers: new HttpHeaders({
              'Content-Type': 'application/json',
              'Authorization': `Bearer ${token}`
            })
          });
      }));
  }
}

获取可观察值

1 个答案: