问如何在heroku上流式传输响应rails应用程序

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module Streameable
  extend ActiveSupport::Concern
  include ActionController::Live

  def send_stream(filename:, disposition: 'attachment', type: nil)
    response.headers['Content-Type'] =
      (type.is_a?(Symbol) ? Mime[type].to_s : type) ||
      Mime::Type.lookup_by_extension(File.extname(filename).downcase.delete('.')) ||
      'application/octet-stream'

    response.headers['Content-Disposition'] =
      ActionDispatch::Http::ContentDisposition.format(disposition: disposition, filename: filename)  # for Rails 5, use content_disposition gem

    # extra: needed for streaming correctly
    response.headers['Last-Modified'] = Time.now.httpdate

    yield response.stream
  ensure
    response.stream.close
  end
end

class ExporterController < ApplicationController
  include Streameable

  def index
    respond_to do |format|
      format.html # index.html
      format.js   # index.js
      format.csv do
        send_stream(attachment_opts) do |stream|
          stream.write "email_address,updated_at\n"

          50.times.each do |i|
            line = "user_#{i}@acme.com,#{Time.zone.now}\n"
            stream.write line
            puts line
            sleep 1  # force slow response for testing respose > 30''
          end
        end
      end
    end
  end

  private

  def attachment_opts
    {
      filename: "data_#{Time.zone.now.to_i}.csv",
      disposition: 'attachment',
      type: 'text/csv'
    }
  end
end

$ curl -i  http://localhost:3000/exporter.csv