python select.py模块 rs,ws,es=select.select(inputs,[],[],1)

# encoding: utf-8
# module select
# from (pre-generated)
# by generator 1.145
"""
This module supports asynchronous I/O on multiple file descriptors.

*** IMPORTANT NOTICE ***
On Windows and OpenVMS, only sockets are supported; on Unix, all file descriptors.
"""
# no imports

# functions

def select(rlist, wlist, xlist, timeout=None): # real signature unknown; restored from __doc__
    """
    select(rlist, wlist, xlist[, timeout]) -> (rlist, wlist, xlist)
    
    Wait until one or more file descriptors are ready for some kind of I/O.
    The first three arguments are sequences of file descriptors to be waited for:
    rlist -- wait until ready for reading
    wlist -- wait until ready for writing
    xlist -- wait for an ``exceptional condition''
    If only one kind of condition is required, pass [] for the other lists.
    A file descriptor is either a socket or file object, or a small integer
    gotten from a fileno() method call on one of those.
    
    The optional 4th argument specifies a timeout in seconds; it may be
    a floating point number to specify fractions of seconds.  If it is absent
    or None, the call will never time out.
    
    The return value is a tuple of three lists corresponding to the first three
    arguments; each contains the subset of the corresponding file descriptors
    that are ready.
    
    *** IMPORTANT NOTICE ***
    On Windows and OpenVMS, only sockets are supported; on Unix, all file
    descriptors can be used.
    """
    pass

# classes

class error(Exception):
    # no doc
    def __init__(self, *args, **kwargs): # real signature unknown
        pass

    __weakref__ = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
    """list of weak references to the object (if defined)"""

1. #select的原型为(rlist,wlist,xlist[,timeout]),

2. # 其中rlist是等待读取的对象，

3. # wlist是等待写入的对象，

4. # xlist是等待异常的对象，

5. rs,ws,es=select.select(inputs,[],[],1)

#1、select函数阻塞进程，直到inputs中的套接字被触发（在此例中，套接字接收到客户端发来的握手信号，从而变得可读，满足select函数的“可读”条件），rs返回被触发的套接字（服务器套接字）；  

redis websocket select结合推送消息

@get('/websocket', apply=[websocket])
def main(environ, start_response):
    channel = rd.pubsub()
    uid = environ.get('QUERY_STRING').split("=")[1]
    channel.subscribe(uid)
    rd_fd = channel.connection._sock.fileno()

    while True:
        data = select.select([rd_fd], [], [], 4.0)
        for fd in data[0]:
            if fd == rd_fd:
                msg = channel.parse_response()
                ws = environ["wsgi.websocket"]
                if msg[0] == 'message':
                    ws.send(msg[2])

参考：https://blog.csdn.net/vito21/article/details/53319306

https://blog.csdn.net/Coder_py/article/details/76187946