Running Node.js on a server

Node.js is a little different to how you're used to using PHP, in that it doesn't replace PHP but PHP and Apache.

Your Node.js program is responsible for accepting every request and deciding how you respond to it. It isn't just something you can "access on the pages when needed", it serves the pages itself.

For example, instead of serving an index.php containing code to run when you visit http://example.com/, your Node.js server would contain code to run when you visit http://example.com, and decide how to handle the path /:

index.php

<?php
echo 'Hello world';

server.js

var http = require('http');
http.createServer(function(req, res) {
  if(req.url === '/') {
    res.end('Hello world');
  } else {
    res.statusCode = 404;
    res.end(req.url + ' not found');
  }
}).listen(3000);

Node.js is typically used with Apache or Nginx or [insert server here] as a reverse proxy, to forward external requests on to an internal Node.js server.

If all this sounds a little daunting, and you're thinking "why can't I just embed Node.js in pages like PHP", there's always PNP. However, it's probably not suitable for production usage, and at that point you might as not be using Node.js, as you won't have access to any asynchronous APIs, which includes pretty much everything.

I'd recommend the Node.js for PHP Developers blog series, which serves as a great introduction to the major concepts of Node.js.