Nodejs+Express使用 cors 中间件解决跨域问题

使用Nodejs+Express框架搭建web服务器，如果需要实现CORS，即Cross-Origin Resource Sharing，跨源资源共享(俗称跨域资源共享)，那么就应该在服务器端引入中间件cors

cors中间件的引入方式如下

const cors = require('cors');                   //allow CORS
app.use(cors());

127.0.0.1:8051服务器代码全文如下

/*----------------------Set up express server----------------------------*/
var express = require('express');               //express package
var app = express();                            //use express package
var jsonFile = require('jsonfile');             //jsonfile package

const cors = require('cors');                   //allow CORS
app.use(cors());

//set up the interprate method of express
app.use(express.json());
//set up the static path as '/public'
app.use('/public', express.static('public'));

//listen 8051 port
var server = app.listen(8051, function () {
    var host = server.address().address
    var port = server.address().port
    console.log("Simulation module server is started, IP address is localhost:%s", port)
})

//go to the main page (index.html)
app.get('/', function (req, res) {
    console.log('收到')
    res.send('收到')
})

这样从127.0.0.1:8050/public/index.html可以正常访问127.0.0.1:8051服务器，返回结果为一个字符串“收到”