example_image_moderation.rb

require 'rubygems'
require 'sinatra'
require 'dm-core'
require 'net/http'
require 'uri'

class ImageModeration
  include DataMapper::Resource
  property :id,           Integer, :serial=>true
  property :image_url,    Text
  property :created_at,   DateTime
  property :results,      Text
  property :offensive,    String
  property :finished_at,  DateTime

  # Send image details to Houdini
  def self.start
    moderation = self.create(:created_at => Time.now, :image_url => image_url)
    data = {
      'image_url' => 'http://images.google.com/images/life_hpp7.jpg',
      'postback_url' => "http://YOUR_DOMAIN.com/image_moderation_results",
      'client_data' => moderation.id}
    url = URI.parse('http://gohoudini.com/moderate_image')
    Net::HTTP.post_form(url, data)
  end
end

# Receive image moderation answer from Houdini
post '/image_moderation_results' do
  moderation = ImageModeration.get(request.POST["client_data"])
  moderation.update_attributes(:results => request.POST, :offensive => request.POST["offensive"], :finished_at => Time.now)
end