node.js - socket.IO 【 require('socket.io').listen(80);】不解！找遍所有群也未解决，求高手解答！

Question

官网上有一个这样的示例(http://socket.io/docs/)：

此处，说明是会创建一个http请求，但是我没明白，这个请求创建了之后，要怎么访问呢，我看代码engine.io.js里，有这样一段代码：

     function listen(port, options, fn) {
    if (‘function’ == typeof options) {
    fn = options;
    options = {};
    }

    var server = http.createServer(function (req, res) {
        res.writeHead(501);
        res.end('Not Implemented');
    });

    server.listen(port, fn);

    // create engine server
    var engine = exports.attach(server, options);
    engine.httpServer = server;

    return engine;
    };

创建的一个501请求，但是这样创建的一个，用什么方法可以访问呢？？
还有就是如果才能触发 connection事件呢？？
一直没搞明白这两个问题

按我的理解是，创建了一个HTTP服务，然后通过浏览器去访问，然后再通过客户端的 var socket = io(‘http://localhost’);来建立长链接，然后触发后端的才能触发connection事件。

但是，最上面的代码，不清楚在哪个地方可以触发事件，并且怎么访问建立的HTTP服务！请知道的解答一下，谢谢

Answer 1

According to my understanding, an HTTP service is created, then accessed through the browser, and then the long link is established through the client's var socket = io('http://localhost');, and then the backend is triggered. To trigger the connection event.

This understanding is wrong. The questioner probably thinks that the URL /chat can be accessed directly through the browser. This is wrong. This URL is just a channel of socket.io, not a real URL.

The Socket.io example misses a very important part, that is, the following code. Its function is to return an html page, and the content of the page is the client's index.html.

javascript// 这段代码直接来自 socket.io 的第一个例子：Using with Node http server

var app = require('http').createServer(handler)
var io = require('socket.io')(app);
var fs = require('fs');

app.listen(80);

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);
  });
}

After writing this code, the complete socket.io client/server process can be realized:

1. The client accesses the server / and gets index.html;
2. Call index.html in client io.connect('http://localhost/chat') to create a connection;
3. The server receives the connection event of /chat channel and executes the code of chat.on('connection').

var io = require('socket.io').listen(80); This code is a trap, and a * for beginners. In fact, when using socket.io, you don’t write it like this. Generally, you use one of the three Using with... usages to provide services.