nodejs express服务端跨域的设置

var express = require('express')
var cors = require("cors")
var session = require("express-session")
var bodyParser = require("body-parser");
var whitelist = require("./config/whitelist.json")
var userlist = require("./config/user.json")
var app = express();
console.log('userlist', userlist)
app.use(express.static('./public'))
app.use(cors())
app.use(bodyParser.urlencoded({extended: false}));
app.use(session({
    secret: +new Date()+"abc",
    cookie: {maxAge: 10 * 1000}
}))
app.all('*', function (req, res, next) {
    res.header("Access-Control-Allow-Origin", "http://localhost:8080");
    res.header("Access-Control-Allow-Headers", "Content-Type,Content-Length, Authorization, Accept,X-Requested-With");
    res.header("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS");
    res.header("Access-Control-Allow-Credentials", true);
    res.header("X-Powered-By", ' 3.2.1')
    if (req.method == "OPTIONS") res.send(200);/*让options请求快速返回*/
    else next();
});

app.get("", function (req, res) {
    res.send("home")
})
app.get("/", function (req, res) {
    console.log("It works! version: ", process.env.npm_package_version);
    console.log("req-cookie", req.headers.cookie);
    res.send("It works! version: " + process.env.npm_package_version);
});
// 登录接口
app.post("/login", function (req, res, next) {
    let code, msg, data;
    const {username, password} = req.body;

    if (username && userlist[username] === password) {
        req.session.username = username;
        code = 0;
        msg = "success";
        data = "登录成功"
    } else {
        code = -1;
        msg = "error";
        data = "账号或者密码不正确"
    }
    res.send({code, msg, data})
})

app.get("/identity", function (req, res, next) {
    let code = 0, msg = "", data = {anonymous:true,username:""};
    console.log("req.session", req.session);
    if (req.session && req.session.username) {

        data.anonymous=false;
        data.username=req.session.username;

    } else {
        data.anonymous = true;

    }
    res.send({data, code})
})
app.listen(3003);
console.log("localhost:3003")