Stream CSV data in Rails 3.2

export_controller.rb

class ExportController < ApplicationController

  def index
  #suitable for streaming data, no caching http://wiki.nginx.org/X-accel#X-Accel-Buffering
    headers['X-Accel-Buffering'] = 'no'
    headers["Cache-Control"] ||= "no-cache"
    headers.delete("Content-Length")

    headers["Content-Type"] = "text/csv"
    headers["Content-disposition"] = 'attachment; filename="gaga.csv"'

    response.status = 200
    self.response_body = csv_lines
  end

  def csv_lines

    Enumerator.new do |y|
      y << "name, number\n"

      5.times do |i|
        y << "gaga, #{i}\n"
        sleep 2
      end
    end
  end

end