node.js / Express / Connect / Socket.io的关系

Question

I'm confused. The main question I have is, when to use pure node.js, when shall I use a framework/MVC like "express" or "connect".

I know that "express" is just adding a bunch of functionality to "connect", but what is it really good for? Lets say, I want all my HTTP stuff do against an "Apache" server and only do some partial stuff with node.js (like WebSocket connections, CouchDB, etc.).

Would it make sense in this scenario to use "express" or "connect" for some reason?

As far as I know, Socket.IO also handles HTTP requests as a fallback, so would it be just enough to use Socket.IO for those needs ?

What else is the big advantage using Express/Connect ?

Answer 1

Express (or Connect) is an application framework for HTTP web applications. It's the entry point of your application. It provides some very common functionnalities such as :

• HTTP Server
• URL Routing
• Request args
• Sessions

It also allows other functionnalities to be easily used (they are called middleware) such as Authentication handling, templating.

If you just want to implement a pub/sub service through SocketIO, without any pages or other API, just use the Socket.io library (S.io homepage example) :

var io = require('socket.io').listen(80);

io.sockets.on('connection', function (socket) {
    socket.emit('news', { hello: 'world' });
    socket.on('my other event', function (data) {
        console.log(data);
    });
});

If you want to use Socket.io within a more complexe application, serving pages and API, you can (must ?) integrate it with Express (see How To Use )

Answer 2

Hi I have been using Expressjs for some time now and find it particularly useful for the Jade templating engine it provides by default. Jade is a new templating language and though I admit it takes some time to get familiar with it, its pretty useful. You can write conditionals, mixins, pass variables to your pages, use partials etc. It just makes client side html really easy. Also expressjs sets up your view, javascript, stylesheets directory structure... If followed properly catching responses and rendering html pages are a matter of couple of line of codes. As discussed above, the http middlewear is a lot easier to implement..