gae 배포 이후 react axios 문제

강의 내용대로 react 합쳐서 gae로 올렸는데 이런 오류가 발생합니다. 뭐가 문제인지 감이 안 잡혀여쭤봅니다.

파일 구성

blog-manager에서 gcloud app deploy 했습니당


server.js

const express = require('express');
const app = express();
const path = require('path');

app.use(express.urlencoded({extended: true}))

const MongoClient = require('mongodb').MongoClient;
app.set('veiw engine','ejs')
const methodOverride = require('method-override');
app.use(methodOverride('_method'));
require('dotenv').config()

app.use(express.json());
var cors = require('cors');
app.use(cors());

var db;

const url = process.env.DB_URL;

MongoClient.connect(url,function(err,clinet){

if(err) return console.log(err)

 db = clinet.db('blog-manager');
 
 app.listen(process.env.PORT, function(){
 console.log(process.env.PORT)
 })
});

app.use(express.static(path.join(__dirname, '/blog-manager/build/')));

app.get('/',function(req, res){
 res.sendFile(__dirname + '/blog-manager/build/index.html')
})

// /add로 db에 때려 넣기

app.post('/add',function(req,res){

 db.collection('count').findOne({name: 'dataNum'}, (err, result)=>{
 console.log(result.totalPost)
var totalPost = result.totalPost;
var keywords = req.body.keywords.replace(" ").split(',');
 
 db.collection('data').insertOne({_id : totalPost+1, title: req.body.title, keywords: keywords, writer: req.body.id}, ()=>{
 console.log('저장완료');
 db.collection('count').updateOne({name:'dataNum'},{ $inc: {totalPost:1}},(err, result)=>{
if(err) return console.log(err);
 console.log('data 증가 성공');
 db.collection('user').updateOne({id: req.body.id},{ $push: {data: totalPost+1}})
 res.redirect('/myPage/'+req.body.id); //res는 하나만 써야함.
 })
 })
 })
})

app.get('/list',(req,res)=>{
 db.collection('data').find().toArray((err,result)=>{
if(err) return err
 res.send(result)
 })
})

// app.get('/list/:id',(req,res)=>{
// var list = [];
// db.collection('user').findOne({id: req.params.id}, (err, result)=>{
// try {
// db.collection("data").find({ _id: result.data[i] }).toArray(
// (err, resultData) => {
// console.log("result: " + resultData[0])
// list.push(resultData[0])
// }
// )

// } catch (err) {
// console.log(err);
// }
// })
// })

app.delete('/list',(req, res)=>{
 db.collection('data').deleteOne({_id: parseInt(req.body._id)},(err,result)=>{
 console.log('삭제함')
 res.status(200);
 })
})

app.post('/register',(req, res)=>{
 db.collection('user').insertOne({id: req.body.id, pw: req.body.pw, data: []},(err,result)=>{
 console.log('등록함')
 res.redirect("/login")
 })
})

const passport = require('passport');
const LocalStrategy = require('passport-local').Strategy;
const session = require('express-session');

app.use(session({secret : '비밀코드', resave : true, saveUninitialized: false}));
app.use(passport.initialize());
app.use(passport.session());

app.post('/login', passport.authenticate('local',{
failureRedirect: '/login'
}),(req, res)=>{
 res.redirect('/')
})

const isLogin = (req, res, next) => {
if (req.user){
next()
 } else {
 res.send(false)
 }
}

app.get('/user',isLogin,(req, res)=>{
 res.send(req.user)
})

passport.use(new LocalStrategy({
usernameField: 'id',
passwordField: 'pw',
session: true,
passReqToCallback: false,
 }, (id, pw, done) => {
//console.log(입력한아이디, 입력한비번);
 db.collection('user').findOne({ id: id }, function (err, result) {
if (err) return done(err)
 
if (!result) return done(null, false, { message: '존재하지않는 아이디요' })
if (pw == result.pw) {
return done(null, result)
 } else {
return done(null, false, { message: '비번틀렸어요' })
 }
 })
 }));

// 세션등록하기

passport.serializeUser((user, done)=>{
done(null, user.id)
})

passport.deserializeUser((id, done)=>{
 db.collection('user').findOne({id:id}, (err, result)=>{
done(null, result)
 })
})

app.get('*', function (req, res) {
 res.sendFile(path.join(__dirname, '/blog-manager/build/index.html'));
 });
// /list db에서 가져오는