按照文档在我的 Firebase 函数上给出 CORS 策略错误

Question

我有一个网络应用程序已经使用 Firebase 和 Firestore 进行身份验证。我想从网络应用程序调用我的函数，所以我使用

onCall

，因为函数文档推荐它。

当我在本地主机上运行我的网络应用程序时，我收到此错误：

blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

服务器：

import { onCall, HttpsError } from "firebase-functions/v2/https";
import { onDocumentWritten } from "firebase-functions/v2/firestore";

import * as logger from "firebase-functions/logger";

exports.plusone = onCall({
    cors: true,
}, (request) => {
    const email = request.auth?.token.email;
    const num = request.data.num;

    logger.log(email + " tried to increase his number by one:" + num);

    return {
        finalNum: num + 1,
    }
})

客户：

const functions = getFunctions();
const plusone = httpsCallable(
  functions, 'plusone'
)
plusone().then((result) => {
    console.log(result.data.message)
})

Answer 1

CORS 是一项通过浏览器强制执行的安全功能，已经有相当长一段时间了，只有服务器（在您的情况下是云功能）允许的来源才允许从该客户端（浏览器）发出请求，这就是为什么您会在第一名。

您已经启用了cors，您应该允许您的源向您的云功能发出请求

const { onRequest } = require("firebase-functions/v2/https");

exports.plusone = onRequest(
  { cors: true },
  (req, res) => {
    res.set('Access-Control-Allow-Origin', '*'); // do this for development purpose, when you are in production change that to your origin where you are hosting your webpage
    res.status(200).send("Hello world!");
  }
);