Monday, August 30, 2010

Setting up Node.js and npm on Mac OSX

Node.js is gaining a lot of speed and is an exciting new development framework. Here's a quick overview of how to get node.js working on OSX along with npm, the package manager for node.

Update: There are now packages available for OSX and Windows if you prefer a one click install for Node.js and NPM. To install from source you probably know what you are doing but this article might help.

Install Homebrew

Homebrew is the package manager that Apple forgot. Written in Ruby it allows you to quickly and easily compile software on your Mac. Instructions for installing Homebrew are in the README so I won't repeat them here. You will need to install Developer Tools for Mac which you are installed as part of Xcode. Xcode is available for free - it is a pretty hefty download but you'll need it.

Install Node.js via homebrew

Once Homebrew is installed you can go ahead and install Node.js

brew install node

Easy! Now create a file called server.js and paste in the example server code

var http = require('http');
http.createServer(function (req, res) {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello World\n');
}).listen(8124, "127.0.0.1");
console.log('Server running at http://127.0.0.1:8124/');

Save the file and from the console run

node server.js

Now you can visit http://127.0.0.1:8124/ with your favourite browser and you are up and running with server side JavaScript.

At this point it is probably a good idea to consult the excellent Node.js documentation. This will help you understand what Node.js is and what it can do.

Installing npm

Node.js is pretty low level so lots of people have created modules for Node. Thankfully there is already a package manager for Node in npm to help you manage these.

For various reasons the package was recently removed from Homebrew so you'll need to install it manually.

curl https://npmjs.org/install.sh | sh

If executing scripts from curl makes you nervous you can download the source and then install:

git clone http://github.com/isaacs/npm.git
cd npm
sudo make install

The install will spit out some advice about paths. I found on my setup everything worked other than having to set NODE_PATH.

NODE_PATH tells Node.js where to look for modules. This means you can do things like

var client = require 'redis-client'

instead of specifying the full path.

To make sure my shell knows where to find Node.js modules I added

export NODE_PATH="/usr/local/lib/node"

to my .bashrc file. As some modules have executables you will also need to add /usr/local/share/npm/bin to your PATH. Here's how mine looks

export PATH="/usr/local/bin:/usr/local/sbin:/usr/local/mysql/bin:/usr/local/share/npm/bin:$PATH"

My full .bashrc file is available here if you need an example. Make sure you reload your shell with

source ~/.bashrc

so the changes are applied.

Installing modules

Now we are set up we can install Node modules using npm. Express is a good place to start - it is a Node framework inspired by Sinatra.

npm install express

This provides a solid base to start developing with Node.js including jade the haml inspired Node tempting engine. There is more excellent documentation available for express too.

That's it - go create!