Shortening socket timeout using Timeout::timeout(n) does not seem to work for me

Question

I found what I thought should work perfectly at https://stackoverflow.com/questions/517219?tab=oldest#tab-top but, it did not work for me.

I have Ruby 1.9.1 installed on Windows and, when I try the example "is_port_open" test, it does not work. The socket call still takes around 20 seconds to timeout no matter what value I set for the timeout. Any ideas why?

Answer 1

The following code seems to work with ruby 1.9.1 on Windows:

require 'socket'

def is_port_open?(ip, port)
  s = Socket.new(Socket::AF_INET, Socket::SOCK_STREAM, 0)
  sa = Socket.sockaddr_in(port, ip)

  begin
    s.connect_nonblock(sa)
  rescue Errno::EINPROGRESS
    if IO.select(nil, [s], nil, 1)
      begin
        s.connect_nonblock(sa)
      rescue Errno::EISCONN
        return true
      rescue Errno::ECONNREFUSED, Errno::EHOSTUNREACH
        return false
      end
    end
  end

  return false
end

I haven't figured out yet why the original is_port_open?() code doesn't work on Windows with ruby 1.9.1 (it works on other OSes).