javascript - Cors 似乎在我的 Node 服务器上默认启用。我错过了什么吗？

Question

所以我有一个非常基本的 Node 和 Express 服务器，如下所示。没有中间件或任何东西，但我仍然能够记录 axios 对 google.com 的响应。这是否会导致 cors 错误，导致我必须使用中间件或设置服务器来发出跨源请求？对于 CORS 仍然有些不清楚，非常感谢任何澄清。谢谢!

var express = require('express');
var app = express();
var axios = require('axios');

app.on('listening', () => {
    axios.get('https://google.com')
    .then(response => console.log(response.data));
});

app.get('*', function(request, response){
  response.sendfile('./dist/index.html');
});

app.use(function(err, req, res, next) {
  if (err) {
      res.status(500).send(err);
      console.log(err.message);
  }
  next();
});

app.listen(process.env.PORT || 3000, () => {
    app.emit('listening');
    console.log('listening on 3000');
});

Answer 1

CORS 是一个浏览器的东西。它不适用于服务器端代码(在 Node、PHP、Java 等中)。来自 the spec :

This document defines a mechanism to enable client-side cross-origin requests.

及以后

User agents commonly apply same-origin restrictions to network requests. These restrictions prevent a client-side Web application running from one origin from obtaining data retrieved from another origin, and also limit unsafe HTTP requests that can be automatically launched toward destinations that differ from the running application's origin.

(我的重点)