Steps towards RESTful Piano, semantics provided with RDF... next logic step!

love.rb

# Instructions
# ============
#
# Put some files with no extension in /data and see the server
# read them (in stdout).
#
# > gem 'piano'
# > gem 'addressable'
# > gem 'mime-types'

require "piano"
require "addressable/uri"
require "addressable/template"
require "mime/types"

module Piano
  class Resource
    TEMPLATES = [
      Addressable::Template.new( "http://{host}/{identifier}{-prefix|.|type}" ),
      Addressable::Template.new( "http://{host}/{identifier}" ),
      Addressable::Template.new( "{identifier}{-prefix|.|type}" ),
      Addressable::Template.new( "{identifier}" )
    ]
    
    attr_accessor :identifier, :type, :content, :uri
    
    def initialize identifier
      parse identifier
      
      # Esto es una lectura elemental del contenido. Deberia hacerse en 
      # un criterio relacionado con, sea el formato pedido en la extension
      # o sea el formato pedido en el Accept
      if File.exist? "#{Base.data}/#{@identifier}"
        @content = File.read "#{Base.data}/#{@identifier}"
      end
    end
    
    def parse identifier
      @uri = Addressable::URI.parse identifier
      extracted = nil
      Resource::TEMPLATES.each do |template|
        extracted = template.extract @uri
        break unless extracted.nil?
      end
      raise "The URI templates for Resource are broken, please check them" if extracted.nil?

      @identifier = extracted["identifier"]
      
      # MIME type is the best
      if extracted.has_key? "type" 
        
        # Load from extension...
        mimes = MIME::Types.type_for extracted["type"]
        # ...or from MIME in URI
        mimes = MIME::Types[extracted["type"]] if mimes.empty?
        @type = mimes.first

        # Total fallback: plain URI type, MIME or whatever
        @type = extracted["type"] if @type.nil?
      end
    end
    
    def to_s
      "#{@identifier} [#{@type}]: #{@content}"
    end
  end
  
  class Base
    enable :sessions
    
    helpers do
      # Returns nil if no flash message was setted
      # otherwise returns the message
      def flash?  
        session[:flash]
      end
      
      # Sets the flash message or returns it in a non-destructive manner
      def flash data = nil
        if data
          session[:flash] = data
        else
          session[:flash]
        end
      end      

      # Destructively returns the flash message
      def flash!
        flash_text = session[:flash]
        session.delete :flash
        return flash_text
      end      

      def resource name = nil
        if name
          @resource = Resource.new name
        else
          @resource
        end
      end
    end
    
    before "*" do
      resource request.path[1..-1]
      puts resource
    end
  end
end

puts Piano::Base.data

Piano::Base.play!