Otto - 0.3

Auto-define your rack-apps in plain-text.

Overview

Apps built with Otto have three, basic parts: a rackup file, a ruby file, and a routes file. If you've built a Rack app before, then you've seen a rackup file before. The ruby file is your actual app and the routes file is what Otto uses to map URI paths to a Ruby class and method.

A barebones app directory looks something like this:

$ cd myapp
$ ls
config.ru app.rb routes

See the examples/ directory for a working app.

Routes

The routes file is just a plain-text file which defines the end points of your application. Each route has three parts:

  • HTTP verb (GET, POST, PUT, DELETE or HEAD)
  • URI path
  • Ruby class and method to call

Here is an example:

GET   /                         App#index
POST  /                         App#receive_feedback
GET   /redirect                 App#redirect
GET   /robots.txt               App#robots_text
GET   /product/:prodid          App#display_product

# You can also define these handlers when no 
# route can be found or there's a server error. (optional) 
GET   /404                      App#not_found
GET   /500                      App#server_error

App

There is nothing special about the Ruby class. The only requirement is that the first two arguments to initialize be a Rack::Request object and a Rack::Response object. Otherwise, you can do anything you want. You're free to use any templating engine, any database mapper, etc. There is no magic.

class App
  attr_reader :req, :res

  # Otto creates an instance of this class for every request
  # and passess the Rack::Request and Rack::Response objects.
  def initialize req, res
    @req, @res = req, res
  end

  def index
    res.header['Content-Type'] = "text/html; charset=utf-8"
    lines = [
      '<img src="/img/otto.jpg" /><br/><br/>',
      'Send feedback:<br/>',
      '<form method="post"><input name="msg" /><input type="submit" /></form>',
      '<a href="/product/100">A product example</a>'
    ]
    res.body = lines.join($/)
  end

  def receive_feedback
    res.body = req.params.inspect
  end

  def redirect
    res.redirect '/robots.txt'
  end

  def robots_text
    res.header['Content-Type'] = "text/plain"
    rules = 'User-agent: *', 'Disallow: /private'
    res.body = rules.join($/)
  end

  def display_product
    res.header['Content-Type'] = "application/json; charset=utf-8"
    prodid = req.params[:prodid]
    res.body = '{"product":%s,"msg":"Hint: try another value"}' % [prodid]
  end

  def not_found
    res.status = 404
    res.body = "Item not found!"
  end

  def server_error
    res.status = 500
    res.body = "There was a server error!"
  end
end

Rackup

There is also nothing special about the rackup file. It just builds a Rack app using your routes file. 

require 'otto'
require 'app'

app = Otto.new("./routes")

map('/') { 
  run app
}

See the examples/ directory for a working app.

Installation

Get it in one of the following ways:

$ gem install otto
$ sudo gem install otto
$ git clone git://github.com/delano/otto.git

You can also download via tarball or zip.

More Information

In the wild

Services that use Otto:

Credits

License

See LICENSE.txt