我正在尝试获得基本的套接字连接。
服务器看起来像这样:
const express = require("express");
const app = express();
const port = 4000;
const server = require("http").createServer(app);
let io = require("socket.io")(server);
app.get("/", (req, res) => res.send("Server up"));
io.on("connection", socket => {
console.log("a user connected");
});
app.get("/", (req, res) => res.send("Hello World!"));
app.listen(port, () => console.log(`Example app listening on port ${port}!`));
React 组件如下所示:
import React, { useState, useEffect } from "react";
import io from "socket.io-client";
const ChatScreen = () => {
const socket = io('localhost:4000');
useEffect(() => {
}, []);
return (
<div className="chatScreen">HI</div>
);
};
export default ChatScreen;
正如我从阅读中得到的,我应该在服务器中收到一个 console.log“用户已连接”。 但我收到这两个错误:
Access to XMLHttpRequest at 'http://localhost:4000/socket.io/?EIO=3&transport=polling&t=N2xxl7i'
from origin 'http://localhost:3000' has been blocked by CORS policy: No 'Access-Control-Allow-
Origin' header is present on the requested resource.
还有
polling-xhr.js:267 GET http://localhost:4000/socket.io/?EIO=3&transport=polling&t=N2xy65_
net::ERR_FAILED
我该怎么做?
最佳答案
在您的 Node js 应用程序中,您可以尝试在 var app =express();
之后添加以下内容:
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();
});
关于node.js - 客户端和服务器端之间的 Socket.io 连接失败(Reacr/Node.js),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/60592030/