Empowering Express with Node modules

Express does not come packed with a huge bunch of built-in libraries to perform tasks that are beyond a basic website. Express is very minimal. But that does not mean that it is not capable of performing complex tasks.

You have a huge collection of Node modules on the npm registry that can be easily plugged in to your app and used for performing all sorts of tasks in the app.

In Chapter 1, What is Express?, we were introduced to Node modules, and we learned how to write them. We also found out that they can be used to modularly extend the power and capability of Express.

You could write your own Node modules to accomplish many things, but anything you are trying to achieve, probably there is an excellent open source Node module out there already. You just need to find the right module, install it, and use it in your app.

Let's find out how we can install and use a Node module from the NPM registry. We will install a .ini file parsing module named iniparser and use it in our app:

$ npm install iniparser
npm WARN package.json application-name@0.0.1 No README.md file found!
npm http GET https://registry.npmjs.org/iniparser
npm http 304 https://registry.npmjs.org/iniparser
iniparser@1.0.5 node_modules/iniparser

The module has been installed successfully. Create config.ini in the app directory with the following content:

title = My Awesome App
port = 3000
message = You are awesome!

You might have guessed it already, we are going to use this as the configuration file for our app.

Now edit app.js to include the module and use it in our app:

var http = require('http');
var express = require('express');
var app = express();
// Load the iniparser module
var iniparser = require('iniparser');
// Read the ini file and populate the content on the config object
var config = iniparser.parseSync('./config.ini');

app.set('view engine', 'jade');
app.set('views', './views');

app.use(express.static('./public'));
app.use(express.responseTime());
app.use(app.router);
app.use(express.errorHandler());

app.get('/', function(req, res) {
  // Pass two config variables to the view
  res.render('index', {title:config.title, message:config.message});
});

http.createServer(app).listen(config.port, function() {
  console.log('App started on port ' + config.port);
});

While we are at it, we'd like to increase the complexity of the view a little bit more, so go ahead and edit index.jade too:

html
  head
    title #{title}
    script(src='javascripts/main.js')
    link(rel='stylesheet', href='stylesheets/style.css')
  body
    #content
      img(src='images/logo.png')
      p WELCOME
      p #{message}
      #smile

Restart the app and load it in the browser to see the "drastic" changes:

So, you see Express does not come with the inherent ability to parse .ini files, but has the extensibility to be able to do almost anything with the correct Node module, because of which we can parse .ini files and use one in our app.