An Introduction to Geddy

This was the fifth in a series of posts leading up to Node.js Knockout on how to use node.js. This post was written by geddy author and Node.js Knockout judge Matthew Eernisse.

Geddy is a modular, full-service web framework for Node.js, similar to Merb, Rails, Pylons, or Django.

Geddy provides a lot of great features:

• Flexible, robust router with easy RESTful routing (router docs)
• Intelligent content-negotiation (content-negotiation docs)
• Models and validations(model docs)
• Simple, intuitive views with partials support
• Generator utility for easy creation of apps and scaffolding

Installation

There are a few different ways of getting Geddy.

Download the current release, geddy-v0.1.1.tar.gz (2010-08-06)

$ ~/work$ curl -O http://geddyjs.org/dist/geddy-v0.1.1.tar.gz
$ ~/work$ tar -xvzf geddy-v0.1.1.tar.gz
$ ~/work$ cd geddy-v0.1.1
$ ~/work$ make && sudo make install

Or, get the latest Geddy code from GitHub and install it:

$ ~/work$ git clone git://github.com/mde/geddy.git
$ ~/work$ cd geddy
$ ~/work$ make && sudo make install

Geddy can also now be installed with NPM:

$ npm install geddy

If you want to use a database, you'll need database bindings for Node (The Geddy GitHub wiki has docs for setting up SQLite or Postgres). CouchDB does not require database bindings.

NOTE: For Postgres, your database user must have the ability to create databases and tables.

Create an app

Create your Geddy app:

$ ~/work$ geddy-gen app bytor
Created app bytor.

Check if your app runs:

$ ~/work/bytor$ geddy
Geddy worker (pid 5206) running at port 4000 (development mode)

Go to http://localhost:4000/— you should see the following:

“Attention all planets of the Solar Federation”

Geddy has some startup options you can see by doing geddy -h or geddy --help.

RESTful routes

Create a resource-based route with a model stub using geddy-gen resource [model_name]:

$ ~/work/bytor$ geddy-gen resource snow_dog
[ADDED] ./app/models/snow_dog.js
[ADDED] ./app/controllers/snow_dogs.js
resources snow_dogs route added to ./config/router.js
Updated inflections map.
Created view templates.

Geddy's pluralization code isn't that smart yet — if you want a special plural, add it with a comma after the model name (e.g. geddy-gen resource foo,fooes).

There is a nice wiki doc for Geddy's router.

Test your RESTful routes:

$ ~/work/bytor$ geddy
Geddy worker (pid 5206) running at port 4000 (development mode)

Go to [http://localhost:4000/snow_dogs.html][]. You should see the following:

Params

• extension: html
• controller: SnowDogs
• action: index
• method: GET

This is just printing out the contents of the params object in the action.

Now go to [http://localhost:4000/snow_dogs.json][]. You should see the following:

{"params":{"method":"GET","controller":"SnowDogs","action":"index","format":"json"}}

This is Geddy's content-negotiation at work. Geddy tries to do the right thing based on the formats your controller supports, and what the client wants.

There is more detailed info on Geddy's content-negotiation in the wiki doc.

Model properties, etc.

Kill the server (Ctrl+c), and change your model as desired.

$ ~/work/bytor$ vi app/models/snow_dog.js

Add some properties, validations, methods:

var SnowDog = function () {

  this.property('login', 'string', {required: true});
  this.property('password', 'string', {required: true});
  this.property('lastName', 'string');
  this.property('firstName', 'string');

  this.validatesPresent('login');
  this.validatesFormat('login', /[a-z]+/, {message: 'Subdivisions!'});
  this.validatesLength('login', {min: 3});

  // Uncomment the below to validate password confirmation
  // Use with the name of the other field to compare with
  // this.validatesConfirmed('password', 'confirmPassword');

  // Use with any function that returns a Boolean
  this.validatesWithFunction('password', function (s) {
      return s.length > 0;
  });

  // Can define methods for instances like this
  this.someMethod = function () {
    // Do some stuff
  };

};

exports.SnowDog = SnowDog;

The wiki doc on models has more detailed info.

DB config

Turn on database support. Edit your development config file:

$ ~/work/bytor$ vi config/environments/development.js

Set the appropriate values in config.database. See the wiki doc on sample DB configs for examples.

Create the database.

(Remember, with Postgres, your database user has to have enough privileges to create a database.)

$ ~/work/bytor$ geddy-gen db:create
Creating DB for development.js...

Scaffold

Generate your scaffold from the model file you just edited:

$ ~/work/bytor$ geddy-gen scaffold snow_dog
Created client-side model JavaScript files.
Created controller and views for snow_dog.

Fire up the server again:

$ ~/work/bytor$ geddy
Geddy worker (pid 5206) running at port 4000 (development mode)

Go to [http://localhost:4000/snow_dogs.html][], and start creating, editing, removing items.

That’s pretty much it.

The query API for Geddy's models is still pretty limited — it supports only find-by-id and find-by-type. You can take a look at the code in your controller for a closer look at the API.

Get involved

You can help out with Geddy by filing bug reports on GitHub here:

http://github.com/mde/geddy/issues

If you have questions, problems, or feature ideas, you can shoot an e-mail to the mailing list here:

http://groups.google.com/group/geddy

And of course, you can always fork Geddy on GitHub, make improvements, and send a pull request.