Ruby #port_open?

port_check.rb

  def port_open?(host, port, timeout = 5)
    addr = Socket.getaddrinfo(host, nil)
    sockaddr = Socket.pack_sockaddr_in(port, addr[0][3])

    Socket.new(Socket.const_get(addr[0][0]), Socket::SOCK_STREAM, 0).tap do |socket|
      socket.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)

      begin
        # Initiate the socket connection in the background. If it doesn't fail
        # immediatelyit will raise an IO::WaitWritable (Errno::EINPROGRESS)
        # indicating the connection is in progress.
        socket.connect_nonblock(sockaddr)

      rescue IO::WaitWritable
        # IO.select will block until the socket is writable or the timeout
        # is exceeded - whichever comes first.
        if IO.select(nil, [socket], nil, timeout)
          begin
            # Verify there is now a good connection
            socket.connect_nonblock(sockaddr)
          rescue Errno::ECONNRESET
            # coz fuck this, i don't care
            return false
          rescue Errno::ECONNREFUSED
            # coz fuck this, i don't care
            return false
          rescue Errno::EISCONN
            # Good news everybody, the socket is connected!
          rescue
            # An unexpected exception was raised - the connection is no good.
            socket.close
            raise
          end
        else
          # IO.select returns nil when the socket is not ready before timeout
          # seconds have elapsed
          socket.close
          return false
        end
      end
    end

    true
  end

# usage
  begin
    port_open?('google.com', 80)
  rescue Errno::ENETUNREACH, Errno::ECONNREFUSED
    false
  end