google image search proxy for hi-res movie posters

config.ru

require 'movies'
run Sinatra::Application

movies.rb

require 'sinatra'
require 'json'
require 'open-uri'
require 'cgi'

get '/:title/:size' do
  
  props = {
    :ratio => 26.5 / 40.0,
    :size => params[:size],
    :q => '%s+movie+poster' % [CGI.escape(params[:title])]
  }
  
  # return google search results
  open('http://ajax.googleapis.com/ajax/services/search/images?v=1.0&q=%s&rsz=8&imgsz=%s' % [props[:q], props[:size]]) do |r|
    
    # get all images
    imgs = JSON.parse(r.read)['responseData']['results']
    
    # filter vertical images only
    imgs = imgs.select { |i|
      r = i['width'].to_f / i['height'].to_f
      r < 1
    }
    
    # make sure the image has an appropriate ratio
    if(props[:ratio])
      ratio_threshold = props[:ratio] * 0.1
      imgs = imgs.select { |i|
        r = i['width'].to_f / i['height'].to_f
        (r > (props[:ratio] - ratio_threshold)) && (r < (props[:ratio] + ratio_threshold))
      }
    end
    
    # load and proxy image
    open(imgs[0]['url']) do |i|
      content_type i.content_type
      i.read
    end
    
  end
  
end