javascript - 使用 angular2 和 typescript 进行谷歌登录 - 从哪里获得 gapi？

Question

我正在尝试通过以下问题使用 angular2 的 google 登录:Google Sign-In for Websites and Angular 2 using Typescript

但是我得到一个错误:

ORIGINAL EXCEPTION: ReferenceError: gapi is not defined
ORIGINAL STACKTRACE:
ReferenceError: gapi is not defined
    at LoginAppComponent.ngAfterViewInit (http://localhost:3000/app/login.component.js:33:9)
    at DebugAppView._View_AppComponent0.detectChangesInternal (AppComponent.template.js:46:68)
    at DebugAppView.AppView.detectChanges (http://localhost:3000/node_modules/@angular/core//bundles/core.umd.js:12143:18)
    at DebugAppView.detectChanges (http://localhost:3000/node_modules/@angular/core//bundles/core.umd.js:12247:48)
    at DebugAppView.AppView.detectViewChildrenChanges (http://localhost:3000/node_modules/@angular/core//bundles/core.umd.js:12169:23)
    at DebugAppView.AppView.detectChangesInternal (http://localhost:3000/node_modules/@angular/core//bundles/core.umd.js:12154:18)
    at DebugAppView.AppView.detectChanges (http://localhost:3000/node_modules/@angular/core//bundles/core.umd.js:12143:18)
    at DebugAppView.detectChanges (http://localhost:3000/node_modules/@angular/core//bundles/core.umd.js:12247:48)
    at ViewRef_.detectChanges (http://localhost:3000/node_modules/@angular/core//bundles/core.umd.js:10397:69)
    at eval (http://localhost:3000/node_modules/@angular/core//bundles/core.umd.js:9911:88)

显然 gapi 没有定义 - 我可以理解，因为我似乎只声明了一个空变量。

我目前的代码如下:

import {Component, NgZone} from "@angular/core";

declare var gapi: any;

@Component({
    selector: "login",
    templateUrl: "templates/login-template.html"
})
export class LoginAppComponent {
  googleLoginButtonId = "google-login-button";
  userAuthToken = null;
  userDisplayName = "empty";

  constructor(private _zone: NgZone) {
    console.log(this);
  }

  // Angular hook that allows for interaction with elements inserted by the
  // rendering of a view.
  ngAfterViewInit() {
    // Converts the Google login button stub to an actual button.
    gapi.signin2.render(
      this.googleLoginButtonId,
      {
        "onSuccess": this.onGoogleLoginSuccess,
        "scope": "profile",
        "theme": "dark"
      });
  }

  // Triggered after a user successfully logs in using the Google external
  // login provider.
  onGoogleLoginSuccess = (loggedInUser) => {
    this._zone.run(() => {
        this.userAuthToken = loggedInUser.getAuthResponse().id_token;
        this.userDisplayName = loggedInUser.getBasicProfile().getName();
    });
}
}

模板加载正常，只是 gapi 位。

所以我的问题是:我错过了什么？我需要如何定义 gapi 才能工作？

这是我的主要 app.component 代码:

import { Component } from '@angular/core';
import { LoginAppComponent } from './login.component'

@Component({
  selector: 'my-app',
  template: `<script src="https://apis.google.com/js/platform.js?onload=onLoadCallback" async defer></script>
            <script>
            window.onLoadCallback = function(){
              gapi.auth2.init({
                  client_id: 'filler_text_for_client_id.apps.googleusercontent.com'
                });
            }
            </script>
             <h1>Angular2 P.O.C.</h1>
             <login></login>`,
  directives: [LoginAppComponent]
})
export class AppComponent { }

Answer 1

您是否包含了 Google 平台 API 脚本？

<script src="https://apis.google.com/js/platform.js"></script>

参见 this question有关如何在执行代码之前等待 GAPI 脚本加载的说明。