Micropython poll try

polltry.py

try:
    import usocket as socket
    import uselect as select
    import utime as time
    import urandom as random
except ImportError:
    import socket
    import select
    import time
    import random

try:
    import network
    localhost = network.WLAN(network.STA_IF).ifconfig()[0]
except ImportError:
    localhost = '127.0.0.1'

srv_addr = None

POLLFLAGS = (
        (select.POLLIN, 'POLLIN'),
        (select.POLLOUT, 'POLLOUT'),
        (select.POLLHUP, 'POLLHUP'),
        (select.POLLERR, 'POLLERR'),
        )

def pollone(poller, timeout=0):
    r = poller.poll(timeout)

    if r:
        print ('  ' + ' | '.join([f[1] for f in POLLFLAGS if r[0][-1] & f[0]]))
    else:
        print ('  timeout')

def nbtest(addr):
    sock = socket.socket()
    sock.setblocking(False)

    p = select.poll()
    p.register(sock, select.POLLIN | select.POLLOUT)

    print (' - socket')
    pollone(p)

    try:
        sock.connect(addr)
    except OSError:
        pass

    print (' - connecting')
    pollone(p)

    print (' - after sleep')
    time.sleep(1)
    pollone(p)

def srvtest():
    global srv_addr

    sock = socket.socket()
    sock.setblocking(False)

    p = select.poll()
    p.register(sock, select.POLLIN | select.POLLOUT)

    while True:
        srv_addr = socket.getaddrinfo(localhost, random.getrandbits(15) + 32768)[0][-1]
        try:
            sock.bind(srv_addr)
        except OSError:
            pass
        else:
            break

    print ('* server socket bound to port {}'.format(srv_addr[1]))
    pollone(p)

    sock.listen(10)
    print ('* server socket listening')
    pollone(p)

    cl = socket.socket()
    cl.setblocking(False)
    try:
        cl.connect(srv_addr)
    except OSError:
        pass

    print ('* server incomming connection')
    pollone(p, timeout=30000)

def run(oport, cport, uport):
    open_port = socket.getaddrinfo(*oport)[0][-1]
    closed_port = socket.getaddrinfo(*cport)[0][-1]
    unreach_port = socket.getaddrinfo(*uport)[0][-1]

    for d, a in (
            ('open', open_port),
            ('closed', closed_port),
            ('unreach', unreach_port),
            ):
        print ('* {}'.format(d))
        nbtest(a)

    srvtest()

if __name__ == '__main__':
    import sys
    run(
            (sys.argv[1], int(sys.argv[2])),
            (sys.argv[3], int(sys.argv[4])),
            (sys.argv[5], int(sys.argv[6])),
            )

# run this passing 3 (host, port) pairs to run() or to main:
# first is a host/port which is open
# seconf is a host/port which is closed
# third is a host/port which is unreachable (does not send ack/rst)