跨源请求被阻止：同源策略不允许读取远程资源（原因：CORS 请求未成功）

Question

如何在node.js中为socket.io v2.2.0设置cors？（ngx-socket-io：3.4.0）。

尝试如下设置但无法建立连接：

var http = require('http');
var {app,io} = require('../router/nexusservices.router');
var wfwsdk = require('wfw-sdk');
var Service = wfwsdk.getServiceConfigurations('nexusservices');

if (Service) {
 var port = normalizePort(Service.port);
 
  // fix Cross-Origin Request Blocked issue
 app.use(function (req, res, next) {
     res.header("Access-Control-Allow-Origin", "*");
     res.header("Access-Control-Allow-Headers", "*");
     res.header("Access-Control-Allow-Methods", "*");
     if (req.method === "OPTIONS") {
        return res.status(200).end();
     }
     next();
 });

 app.set('port', port);
 /**
 * Create HTTP server.
 */
 var server = http.createServer(app);

 server.listen(port);
 server.on('error', onError);
 server.on('listening', onListening);
  
 io.attach(server);
 io.set('origins', '*:*'); //////// not working