我在使用 socket.io v1.3.2 时遇到传输错误。这只是对 socket.io 的测试，所以我可以熟悉它。
我有一个文件 app.js(直接取自 socket.io 文档):
var app = require('http').createServer(handler);
var io = require('socket.io')(app);
var fs = require('fs');
app.listen(3000);
function handler (req, res) {
fs.readFile(__dirname + '/index.html',
function (err, data) {
if (err) {
res.writeHead(500);
return res.end('Error loading index.html');
}
res.writeHead(200);
res.end(data);
});
}
io.on('connection', function (socket) {
socket.emit('news', { hello: 'world' });
});
还有一个文件index.html:
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title></title>
<link rel="stylesheet" href="">
</head>
<body>
<h1>Socket Test</h1>
<script src="/socket.io/socket.io.js"></script>
<script>
var socket = io.connect('http://localhost');
socket.on('news', function (data) {
console.log(data);
});
</script>
</body>
</html>
在控制台中，我收到以下错误:
GET http://localhost/socket.io/?EIO=3&transport=polling&t=1422782880286-40
(index):1 XMLHttpRequest cannot load http://localhost/socket.io/?EIO=3&transport=polling&t=1422782880286-40. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:3000' is therefore not allowed access. The response had HTTP status code 404.
socket.io.js:3715 engine.io-client:socket socket error {"type":"TransportError","description":0} +37ms
socket.io.js:1402 socket.io-client:manager connect_error +38ms
socket.io.js:1402 socket.io-client:manager reconnect attempt error +1ms
socket.io.js:1402 socket.io-client:manager will wait 5000ms before reconnect attempt +0ms
socket.io.js:3715 engine.io-client:socket socket close with reason: "transport error" +2ms
socket.io.js:3715 engine.io-client:polling transport not open - deferring close +1ms
socket.io.js:1402 socket.io-client:manager attempting reconnect +5s
socket.io.js:1402 socket.io-client:manager readyState closed +0ms
socket.io.js:1402 socket.io-client:manager opening http://localhost +0ms
socket.io.js:3715 engine.io-client:socket creating transport "polling" +5s
socket.io.js:3715 engine.io-client:polling polling +0ms
socket.io.js:3715 engine.io-client:polling-xhr xhr poll +0ms
socket.io.js:3715 engine.io-client:polling-xhr xhr open GET: http://localhost/socket.io/?EIO=3&transport=polling&t=1422782885332-41 +1ms
socket.io.js:3715 engine.io-client:polling-xhr xhr data null +0ms
socket.io.js:3715 engine.io-client:socket setting transport polling +1ms
socket.io.js:1402 socket.io-client:manager connect attempt will timeout after 20000 +3ms
有谁知道如何解决这个错误。我找到了 this discussion ，但一直无法解决问题。
最佳答案
您的代码与 socket.io 网站上的示例之间的区别在于，socket.io 示例代码正在监听端口 80 并在端口 80 上连接 webSocket。您正在监听端口 3000，但尝试连接端口80，因此连接不起作用。 io.connect('http://localhost'); 没有指定端口号，因此它将使用默认的 http 端口，即端口 80。但是，您的 websocket 服务器没有监听端口 80所以连接失败。
解决此问题的最简单方法是更改客户端中的代码行:
var socket = io.connect('http://localhost');
到这里:
var socket = io.connect();
当您省略 URL 时，默认情况下，它将使用当前网页中的域和端口(这是您想要的)。
关于javascript - Socket.Io 传输轮询错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/28261546/