Hacker Please: Initial Work on useless.io

base.rb

module Useless
  class Base
    def call(env)
      [200, {'Content-Type' => 'text/plain'}, ['useless.io: The Useless Platform']]
    end
  end
end

config.ru

require File.dirname(__FILE__) + '/lib/useless'
run Useless

Gemfile

source :rubygems

gem 'rack'

group :test do
  gem 'rspec'
end

group :development do
  gem 'heroku'
end

spec_helper.rb

require File.dirname(__FILE__) + '/../lib/useless'
require 'rack/mock'

street_art.rb

module Useless
  class StreetArt
    def call(env)
      [200, {'Content-Type' => 'text/plain'}, ['useless.io: The Useless Platform / Street Art API']]
    end
  end
end

subdomain_map.rb

module Useless
  # `SubdomainMap` is Rack middleware that delegates to other Rack apps based
  # upon subdomain. It takes two arguments upon initialization:
  #
  # * `base`, the app to be called if there is no subdomain.
  # * `map`, a hash that maps subdomain strings to apps.
  class SubdomainMap
    def initialize(base, map = {})
      @base = base
      @map = map
    end

    def call(env)
      # If the `SERVER_NAME` environment variable has a subdomain
      if env['SERVER_NAME'] =~ /(.*?)\.(?:.*)\..*/
        subdomain = $1
      end

      if subdomain
        # and we can find a corresponding app,
        if app = @map[subdomain]
          # call it and return the result.
          app.call(env)

        # Otherwise, return 403 Forbidden.
        else
          [403, {"Content-Type" => "text/plain"}, []]
        end

      # If there is no subdomain,
      else
        # call the base app and return the result.
        @base.call(env)
      end
    end
  end
end

subdomain_map_spec.rb

require File.dirname(__FILE__) + '/../../spec_helper'

describe Useless::SubdomainMap do
  def map
    default_app = lambda do |env|
      [200, {'Content-Type' => 'text/plain'}, ['Default App']]
    end

    api_app = lambda do |env|
      [200, {'Content-Type' => 'text/plain'}, ['API App']]
    end

    Useless::SubdomainMap.new default_app, 'subdomain' => api_app
  end

  it 'should call the default app if no subdomain is specified' do
    res = Rack::MockRequest.new(map).get('http://useless.info')
    res.should be_ok
    res.body.should == 'Default App'
  end

  it 'should call the appropriate API app if a subdomain is specified' do
    res = Rack::MockRequest.new(map).get('http://subdomain.useless.info')
    res.should be_ok
    res.body.should == 'API App'
  end

  it 'should return a 403 Forbidden if the specified subdomain is not mapped' do
    res = Rack::MockRequest.new(map).get('http://nonexistant.useless.info')
    res.should be_forbidden
  end
end

useless.v1.rb

$:.unshift File.dirname(__FILE__)

module Useless
  def self.call(env)
    [200, {'Content-Type' => 'text/plain'}, ['useless.io: The Useless Platform']]
  end
end

useless.v2.rb

$:.unshift File.dirname(__FILE__)

module Useless
  autoload :Base, 'useless/base'
  autoload :StreetArt, 'useless/street_art'

  autoload :SubdomainMap, 'useless/middleware/subdomain_map'

  def self.call(env)
    map = SubdomainMap.new Base.new,
      'street-art' => StreetArt.new
    map.call(env)
  end
end