在 Firebase Cloud Function 中启用 Cors

Question

我已经编写了一些云函数并部署了它们，现在我正在尝试使用我的 Angular 应用程序访问这些 API，但出现此错误

从源“ http://localhost:4200 ”访问 XMLHttpRequest at 'xxxxxxxxxxxxxxxxxxxxxxxx'已被 CORS 策略阻止：对预检请求的响应未通过访问控制检查：不存在“Access-Control-Allow-Origin”标头在请求的资源上。

我知道我必须在我的云功能中启用 cors，但我以前从未这样做过，所以如果你们能告诉我如何做到这一点会很棒吗？我确实检查了这个线程，但我有点困惑我需要在哪里初始化 cors，我是否也需要安装它的依赖项，我需要在我的云功能中在哪里启用它？这是我的云功能

const functions = require('firebase-functions');


const admin = require("firebase-admin");

const bodyParser = require("body-parser");


admin.initializeApp();

const db = admin.firestore();

const usersCollection = db.collection("users");

exports.addUser = functions.https.onRequest((req, res) => {
    if (req.body.username != null && req.body.firstname != null && req.body.lastname != null && req.body.addr1 != null && req.body.addr2 != null || req.body.username != undefined && req.body.firstname != undefined && req.body.lastname != undefined && req.body.addr1 != undefined && req.body.addr2 != undefined ) {
        let docId = Math.floor(Math.random() * (99999 - 00000));
        let newUser = {
            "username": req.body.name,
            "firstname": req.body.firstname,
            "lastname": req.body.lastname,
            "addr1": req.body.addr1,
            "addr2": req.body.addr2,
        }
        usersCollection.add(newUser).then(snapshot => {
            res.send(200, {
                "message": "User was successfully created"
            })
        });


    } else {
        res.send(400, {
            "message": "All fields are required"
        })
    }
});

Answer 1

有两种方法可以解决这个问题

1. 使用外部库处理OPTIONS调用

科尔斯

2. OPTIONS手动处理呼叫

获取请求方法来自 headers

检查方法是否 OPTIONS

使用200状态码解析 API 。

 exports.addUser = functions.https.onRequest((req, res) => {

res.set('Access-Control-Allow-Origin', '*');
res.set('Access-Control-Allow-Methods', 'GET, PUT, POST, OPTIONS');
res.set('Access-Control-Allow-Headers', '*');

 if (req.method === 'OPTIONS') {
   res.end();
}

else{
        if (req.body.username != null && req.body.firstname != null && req.body.lastname != null && req.body.addr1 != null && req.body.addr2 != null || req.body.username != undefined && req.body.firstname != undefined && req.body.lastname != undefined && req.body.addr1 != undefined && req.body.addr2 != undefined ) {
            let docId = Math.floor(Math.random() * (99999 - 00000));
            let newUser = {
                "username": req.body.name,
                "firstname": req.body.firstname,
                "lastname": req.body.lastname,
                "addr1": req.body.addr1,
                "addr2": req.body.addr2,
            }
            usersCollection.add(newUser).then(snapshot => {
                res.send(200, {
                    "message": "User was successfully created"
                })
            });


        } else {
            res.send(400, {
                "message": "All fields are required"
            })
        }
}
    });