javascript - Firebase HTTP 函数 CORS 问题

Question

从客户端调用 Firebase http 函数时，我无法使其正常工作。以下是客户端上的错误:

OPTIONS https://us-central1-my-app.cloudfunctions.net/my-func 500 ()

Failed to load https://us-central1-my-app.cloudfunctions.net/my-func: 
Response to preflight request doesn't pass access control check:
No 'Access-Control-Allow-Origin' header is present on the requested resource. 
Origin 'http://localhost:3000' is therefore not allowed access. 
The response had HTTP status code 500.

这是我的函数的样子:

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

exports.func = functions.https.onRequest((req, res) => {
  return cors((req, res, () => {
    res.send("hello");
  }));
});

Firebase 功能日志提供以下信息:

TypeError: Cannot read property 'origin' of undefined
    at /user_code/node_modules/cors/lib/index.js:219:39
    at optionsCallback (/user_code/node_modules/cors/lib/index.js:199:9)
    at corsMiddleware (/user_code/node_modules/cors/lib/index.js:204:7)
    at exports.pay.functions.https.onRequest (/user_code/my-func.js:11:10)

请注意，调用堆栈中的 11:10 是这样的:return cors((req, res, () => {

我发出的请求是在请求正文中发送一个带有单个键:值对的对象。我根据我在 SO 上看到的其他问题添加了 cors 中间件，但没有运气!

编辑:添加请求代码:

function post(url, obj) {
  return new Promise((resolve, reject) => {
    const req = new XMLHttpRequest();
    req.open('POST', url, true);
    req.setRequestHeader("Content-type", "application/json");

    req.onload = function() {
      if(req.status == 200) {
        return resolve(req.response);
      }
      else {
        return reject(Error(req.statusText));
      }
    };

    req.onerror = function() {
      return reject(Error("Network Error"));
    };

    req.send(JSON.stringify(obj));
  });
}

Answer 1

程序员错误，像往常一样:

cors((req, res, () => {
    res.send("hello");
  }));

应该是:

cors(req, res, () => {
    res.send("hello");
  });

在 cors 参数周围有一组额外的括号。