recursive.ru

class RecMiddleware
  def initialize(app=nil)
  end

  def call(env)
    env['QUERY_STRING'] ||= "5"

    if env['QUERY_STRING'].to_i <= 1
      [
        200,
        {
          'Content-Length' => "1",
          'Content-Type' => 'text/html',
        },
        ["1"]
      ]
    else
      factor = env['QUERY_STRING'].to_i
      status, headers, body = RecMiddleware.new.call(env.merge('QUERY_STRING' => (factor - 1).to_s))
      new_body = (factor * body[0].to_i).to_s
      [status, headers.merge('Content-Length' => new_body.length.to_s), [new_body]]
    end
  end
end

use RecMiddleware

run lambda{|*args| 'this never gets called' }