Cloud Functions for Firebase - 无法加载 URL：不存在“Access-Control-Allow-Origin”标头

Question

我有一个 angular 2 应用程序，我通过 http 请求调用 Firebase。 但是，无论何时，当我尝试运行该函数时，都会收到此错误：

XMLHttpRequest cannot load https://us-central1-<my-projectId>.cloudfunctions.net/getUserByEmail?email=user@email.com. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:4200' is therefore not allowed access. The response had HTTP status code 500.
    error_handler.js:54 EXCEPTION: Response with status: 0  for URL: null
    ErrorHandler.handleError @ error_handler.js:54
    next @ application_ref.js:348
    schedulerFn @ async.js:93
    SafeSubscriber.__tryOrUnsub @ Subscriber.js:234
    SafeSubscriber.next @ Subscriber.js:183
    Subscriber._next @ Subscriber.js:125
    Subscriber.next @ Subscriber.js:89
    Subject.next @ Subject.js:55
    EventEmitter.emit @ async.js:79
    NgZone.triggerError @ ng_zone.js:333
    onHandleError @ ng_zone.js:294
    ZoneDelegate.handleError @ zone.js:338
    Zone.runTask @ zone.js:169
    ZoneTask.invoke @ zone.js:420
    Subscriber.js:238 Uncaught Response {_body: ProgressEvent, status: 0, ok: false, statusText: "", headers: Headers…}

这是我的 Cloud Function for Firebase index.js文件：

   const functions = require('firebase-functions');
    const admin = require('firebase-admin');
    admin.initializeApp(functions.config().firebase);
    const cors = require('cors')({origin: true});

    /**
     *  Function to get a user by email
     */
    exports.getUserByEmail = functions.https.onRequest((req, res) => {
      cors(request, response, () => {

// This should return a promise from the getUserByEmail function
response.status(200).send(admin.auth().getUserByEmail(req.query.email))
       })
    });

然后这是我在组件中调用函数的方式（假设 HTTP 请求成功）：

this.http.get('https://us-central1-rosebud-9b0ed.cloudfunctions.net/getUserByEmail', {
       search: "user@email.com"
     }).subscribe(data => {
       console.log('data', data);
     })

似乎无论我尝试什么，我都会遇到同样的问题。 我什至尝试将它部署到我的 firebase 托管 URL，但它仍然给我这个错误。 有谁知道我可以在这里做什么？

提前致谢！

Answer 1

所以我在这里犯了几个关键错误。

1. 在初始化 Firebase 应用之前，请确保需要cors 。
2. 确保参数行进cors()函数。

这是更新后的index.js代码：

  const functions = require('firebase-functions');
    const admin = require('firebase-admin');
    const cors = require('cors')({origin: true});
    admin.initializeApp(functions.config().firebase);


    /**
     *  Function to get a user by email
     */
    exports.getUserByEmail = functions.https.onRequest((request, response) => {
      cors(request, response, () => {

// This should return a promise from the getUserByEmail function
response.status(200).send(admin.auth().getUserByEmail(req.query.email))
       })
    });