gistfile1.rb

  def process_text(text, field)
    return if instance_variable_get("@#{field}_processed")
    return if text.blank?
    processed_text = returning(text.dup) do |processed_text|
      text.to_s.scan(/(<img[^>]*src="[^"]*"[^>]*>)/).each do |image| image = image.first
        original_image_content = image.dup
        
        image.to_s.scan(/src="([^"]*)"/).each do |url| url = url.first
          # First pass, import/stage images from user directory into a real asset
          if match = url.match(/^(.*)(\/uploads\/\d*\/.*)$/)
            filename = File.join(RAILS_ROOT, 'public', match[2].gsub(/\?.*$/,''))
            
            file = File.open(filename, 'r')
            puts "Creating asset from #{filename}"
            asset = assets.create :photo => file
            file.close
            
            File.unlink(filename)
            
            image.gsub!(url, asset.photo.url)
          end  
          
          # Second pass, add link to oversized asset version
          next unless match = url.match(/\/\d*\/(\d*)\//)
          if Asset.oversized.find(:first, :conditions => {:id => match[1].to_i})
            # no routes in models makes this semi-painful
            image.gsub!(/^/, "<a target=\"_blank\" href=\"/assets/#{asset.to_param}?dismissable=true\">")
            image.gsub!(/$/, "</a>")
          end
        end
        
        processed_text.gsub!(original_image_content, image) if original_image_content != image
      end
    end
    instance_variable_set("@#{field}_processed", true)
    update_attribute field, processed_text
  end