primedia/xtop

# UrlChecker: Check the status of a given URL by passing a Proc that
# calls the URL and performs some test on the result. A checker must
# return :ok for green and :error for red. Any other result or a timeout
# causes the status line ot be yellow.
module Xtop
  class UrlChecker
    TIMEOUT = 15
    INTERVAL = 0.5

    def self.check(view, checkers={})
      checker_threads = {}

      checkers.each do |url, checker|
        checker_threads[url] = Thread.new do
          case checker.call
          when :ok
            view.update_status(url, "green")
          when :error
            view.update_status(url, "red")
          else
            view.update_status(url, "yellow")
          end
        end

        Thread.new do
          time_elapsed = 0.0
          while true
            sleep(0.1)
            time_elapsed += INTERVAL

            if checker_threads[url].status == false # thread has exited
              break

            elsif time_elapsed > TIMEOUT
              view.update_status(url, "yellow")
              Thread.kill(checker_threads[url])
              break
            end
          end
        end
      end
    end
  end
end