python的callback函数原理

"""

class C(object):

    a = 'abc'

    def __getattribute__(self, *args, **kwargs):

        print("__getattribute__() is called")

        print args

        if args[0] == 'a':

            return object.__getattribute__(self, *args, **kwargs)

        else:

            print '调用函数foo()'

            return object.__getattribute__(self,'foo')()

    def foo(self):

        return "hello"

if __name__ == '__main__':

    c = C()

    print c.foo

"""

class Callback:

    def __init__(self, instance, function_name):

        self.instance = instance # api.self

        self.function_name = function_name # function

    def action(self, params):

        print self.instance.__getattribute__(self.function_name)

        self.instance.__getattribute__(self.function_name)(params)

class Test:

    def __init__(self):

        self.clb = None

    def register(self, clb):

        self.clb = clb # Callback(self, self.function.__name__)

    def do_test(self):

        params = []

        self.clb.action(params)

class Api(object):

    def __init__(self, test_instance):

        test_instance.register(Callback(self, self.function.__name__))

    def function(self, params):

        print params

        print('function')

t = Test()

a = Api(t)

t.do_test()

import errno

import functools

import tornado.ioloop

import socket

def connection_ready(sock, fd, events):

    while True:

        try:

            connection, address = sock.accept()

        except socket.error as e:

            if e.args[] not in (errno.EWOULDBLOCK, errno.EAGAIN):

                raise

            return

        connection.setblocking()

        handle_connection(connection, address)

if __name__ == '__main__':

    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM, )

    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, )

    sock.setblocking()

    sock.bind(("", port))

    sock.listen()

    io_loop = tornado.ioloop.IOLoop.current()  # IOLoop()

    callback = functools.partial(connection_ready, sock)

    io_loop.add_handler(sock.fileno(), callback, io_loop.READ)

    io_loop.start()