A First Look at node.js and Express

With all the hype coming to server-side Javascript lately, especially around Node, I was feeling the need to give it a try to see how it goes. Also, getting back to work after three full weeks of unwired holidays was hard enough to worth deserving some playtime with cool and fun technologies.

Node is described as an Evented I/O Framework for Google’s V8 JavaScript Engine. Think of it as a toolkit to produce high-performance distributed, event-driven and scalable non-blocking network servers. Okay, whatever the way I want to describe the project, it’s buzzword-bingo™. Let’s say it’s mainly about catching events and react accordingly, to make load distribution and parallel processing easier and more effective.

Installing Node

Installation on my Mac went smoothly and took nearly two minutes by compiling it from the sources; here’s how I did (there might be easier or better ways, I don’t really care):

$ mkdir tmp
$ git clone http://github.com/ry/node.git
$ cd node
$ ./configure && make && sudo make install

You now have access to the node executable available on your system.

A simple example of a Node HTTP server (put the code below in a test.js file):

var http = require('http');

var server = http.createServer(function(req, res) {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.write('Hello World');
  res.end();
});

server.listen(3000, "127.0.0.1");

Then launch the created webserver using the command line:

$ node test.js

And point your browser at http://127.0.0.1:3000 to get printed Hello World. Neat, huh?

Introducing Express, a Web Framework on top of Node

Express is a Web framework built on top of Node, HTTP and Connect, allowing easy creation of full-fledged Web applications. It has routing, handles environments as well as several template engines and much more.

Installation is as easy as Node’s one, so here we go:

$ git clone http://github.com/visionmedia/express.git
$ cd express
$ git submodule update --init
$ sudo make install && sudo make install-support

That’s it. You can now write your own test application, eg. in a new hello.js file:

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

app.get('/', function(req, res){
    res.send('Hello World');
});

app.get('/hello/:name', function(req, res){
    res.send('Hello ' + req.param('name') + '!');
});

app.listen(3000, "127.0.0.1");

console.log('Server running at http://127.0.0.1:3000/');

Launch your webapp server by the command line:

$ node hello.js

Express and will create a Node server listening to the local port 3000, so head your favorite browser to http://127.0.0.1:3000/ then http://127.0.0.1:3000/hello/niko to get the picture of what the above code does. Those familiar with Web framework such as rails, django or symfony won’t be much disturbed.

Express also ships with an express executable which provides useful commands. To create a new hello application skeleton, just run:

$ express hello
  create : hello
  create : hello/app.js
  create : hello/logs
  create : hello/public/javascripts
  create : hello/pids
  create : hello/public/stylesheets
  create : hello/public/stylesheets/style.less
  create : hello/public/images
  create : hello/views/partials
  create : hello/views/layout.jade
  create : hello/views/index.jade
  create : hello/test
  create : hello/test/app.test.js

Above command just created an hello project directory where you can cd into and launch the server by its default front controller app.js:

$ cd hello
$ node app.js
Express server listening on port 3000

Note that the generated project skeleton implies using Jade as a template engine and the Less CSS syntax, while one might want to use something else, which is perfectly possible by configuring the project differently.

Next steps documentation will be provided by official Express documentation.

Of course, Express might not be as full-featured as older well-established Web frameworks, but for simple needs it can be pretty easy to setup and deploy, and — probably equally importantly — fun to play with and learn.

Conclusion

As you can see, installing and using Node and Express is quite straightforward, even if you have to dig into the deeper Web to find docs, when they exist. Javascript is a great, agile and well-known language, and taking part of it server-side definitely makes sense if you want my opinion.

Let’s see how this will evolve in the future, as there are not as many backend-oriented libs in JavaScript as there are in other languages like python, ruby or php yet. But more and more node modules are appearing day after day, such as Mongoose or Socket.IO, which I’ll definitely be playing with as soon as possible.

Thanks for your attention, have fun, take care and don’t break the Web.