Express.js - app.listen vs server.listen [英] Express.js - app.listen vs server.listen

问题描述

这可能是一个非常基本的问题，但我根本就不明白。使用Express.js创建应用程序和启动在端口1234上监听的应用程序有什么区别，例如：

This may be a very basic question but I simply don't get it. What is the difference between creating an app using Express.js and starting the app listening on port 1234 for example:

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

//app.configure, app.use etc

app.listen(1234);

并添加一个http服务器：

and adding an http server:

var express = require('express'), http = require('http');
var app = express();
var server = http.createServer(app);

//app.configure, app.use etc

server.listen(1234);

有什么区别？如果我导航到 http：// localhost：1234 - 我得到相同的输出...

What's the difference? If I navigate to http://localhost:1234 - I get the same output...

推荐答案

如果要重复使用HTTP服务器，例如运行套接字，第二种形式（自己创建一个HTTP服务器，而不是使用Express为您创建一个）。 io 在同一个HTTP服务器实例中：

The second form (creating an HTTP server yourself, instead of having Express create one for you) is useful if you want to reuse the HTTP server, for example to run socket.io within the same HTTP server instance:

var express = require('express');
var app     = express();
var server  = require('http').createServer(app);
var io      = require('socket.io').listen(server);
...
server.listen(1234);

但是， app.listen（）返回HTTP服务器实例，所以有一点重写，你可以实现类似的，而不是自己创建一个HTTP服务器：

However, app.listen() also returns the HTTP server instance, so with a bit of rewriting you can achieve something similar without creating an HTTP server yourself:

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

// app.use/routes/etc...

var server    = app.listen(3033);
var io        = require('socket.io').listen(server);

io.sockets.on('connection', function (socket) {
  ...
});

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