Ruby methods in io/nonblock

io_nonblock_demo.rb

#
# Documenting io/nonblock and how the methods (nonblock?, nonblock=, nonblock{}) there behave
#

# server.rb

require 'socket'

TCPServer.open('localhost', 3030) do |server|
  while client = server.accept
    sleep()
  end
end

# Connect to server in IRB

~$ irb
:001 > require 'socket'
 => true 
:002 > require 'io/nonblock'
 => true 
:003 > s = TCPSocket.new('localhost', 3030)
 => #<TCPSocket:fd 5> 
:004 > s.nonblock?
 => false 
:005 > s.nonblock = 0 # put it into nonblocking mode
 => 0 
:006 > s.nonblock?
 => true 
:007 > s.recv(1)
  # This is blocking, so I expected it to raise an exception, but it waits for data instead
:011 > s.nonblock { |s| s.recv(1) }
  # This hangs too

#
# This is how a similar method works in Python, and it's the behavior I was expecting
# from putting a socket into blocking/nonblocking mode
#

# server.py

import SocketServer
import time

class TCPHandler(SocketServer.BaseRequestHandler):
	def handle(self):
		time.sleep(5000)

if __name__ == "__main__":
	server = SocketServer.TCPServer(('localhost', 3030), TCPHandler)
	server.serve_forever()

# Connect to server in python REPL

~$ python
>>> import socket
>>> s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
>>> s.connect(('localhost', 3030))
>>> s.setblocking(0) # set nonblocking mode on the socket
>>> s.recv(1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
socket.error: [Errno 11] Resource temporarily unavailable
  # So we get an exception like I expected, because there's no immediately available data
>>> s.setblocking(1) # put it back into blocking mode
>>> s.recv(1)
  # hangs and waits for data instead of raising exception, like I expected