套接字IO错误“对XMLHttpRequest的访问被CORS策略阻止”

Question

我的应用程序最近收到一个错误

“在'https://my-service-domain/socket.io/?EIO=3

当我连接到 socket.io。我还没有找到这个问题的解决方案，我将详细描述如下图所示，是否有人遇到过此错误。

服务器配置：

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

app.use(function(req, res, next) {
  res.header("Access-Control-Allow-Origin", "*");
  res.header("Access-Control-Allow-Headers", "X-Requested-With");
  res.header("Access-Control-Allow-Headers", "Content-Type");
  res.header("Access-Control-Allow-Methods", "PUT, GET, POST, DELETE, OPTIONS");
  next();
});
var http = require('http');
var server = http.createServer(app);
var io = require('socket.io').listen(server, {log:false, origins:'*:*'});

客户端配置:

var socket = io('https://my-service-domain', {transports: ['polling']});
socket.on(channel_id, function(data){
     // some code
});

我试图切换webocket连接选项var ocket=io（'https：//my-service-dom'，{transport：['webocket']}），我得到了错误

"WebSocket连接到'wss：//my-service-field/socket.io/?EIO=3

Answer 1

如果您使用的是HTTPS协议，请尝试使用以下代码段：

var http = require('https');

Answer 2

它是100%工作的。我花了2个小时在其中，终于找到了答案。只需将代码替换为此代码...

const express = require("express")
var app = express();
var server = app.listen(4000);
var io = require('socket.io')(server, {
    cors: {
      origin: '*',
    }
});

Answer 3

If you are using Socket.IO v3, you need to explicitly enable Cross-Origin Resource Sharing (CORS).
const io = require("socket.io")(httpServer, {
  cors: {
    origin: "http://localhost:8080",
    methods: ["GET", "POST"]
  }
});

httpServer.listen(3000);