Include this in your services directory of your Rails application in order to pull in and parse a hashtag RSS feed from Instagram.

instagrammer.rb

class Instagrammer

  cattr_accessor :config, :url

  class << self
  
    def perform(url, options = {})
      defaults = {:expires_in => 15.minutes }
      self.config = defaults.merge(options)
      self.url = url

      doc = fetch_feed
      
      instagram_images = doc.xpath('//item').map do |i|
        {'title' => i.xpath('title').inner_text,
         'link' => i.xpath('link').inner_text, 
         'description' => i.xpath('description').inner_text,
         'image_url' => i.xpath('//content')[0]['url'],
         'thumbnail_url' => i.xpath('//thumbnail')[0]['url'],
         'author' => i.xpath('//credit').inner_text
        }
      end
      
      instagram_images
    end
    
  end
  
private

  def self.fetch_feed
    unless doc = Nokogiri::HTML(Rails.cache.read(self.url)) and self.config[:cache]
      doc = Nokogiri::HTML(open(self.url))
      doc = doc.remove_namespaces!
      Rails.cache.write(url, doc.to_s, :expires_in => self.config[:expires_in]) if self.config[:cache]
      puts "No cache or expired - grabbed a fresh copy of the feed."
    else
      puts "Hit a cached version of the feed."
    end
    
    doc
  end
  
end