orbit-basic/app/controllers/gridfs_controller.rb

require 'mongo'

class GridfsController < ActionController::Metal
  
  def serve
    gridfs_path = (params[:path]+'.'+params[:format]).gsub("/gridfs/", "").force_encoding("UTF-8")
    begin
      gridfs_file = Mongo::GridFileSystem.new(Mongoid.database).open(gridfs_path, 'r')
      self.response_body = gridfs_file.read
      self.content_type = gridfs_file.content_type
    rescue
      self.status = :file_not_found
      self.content_type = 'text/plain'
      self.response_body = ''
    end
  end
  
end