httpclient.py 文件源码

def __new__(cls, io_loop=None, max_clients=10,
                max_simultaneous_connections=None):
        # There is one client per IOLoop since they share curl instances
        io_loop = io_loop or ioloop.IOLoop.instance()
        if io_loop in cls._ASYNC_CLIENTS:
            return cls._ASYNC_CLIENTS[io_loop]
        else:
            instance = super(AsyncHTTPClient, cls).__new__(cls)
            instance.io_loop = io_loop
            instance._multi = pycurl.CurlMulti()
            instance._curls = [_curl_create(max_simultaneous_connections)
                               for i in xrange(max_clients)]
            instance._free_list = instance._curls[:]
            instance._requests = collections.deque()
            instance._fds = {}
            instance._events = {}
            instance._added_perform_callback = False
            instance._timeout = None
            instance._closed = False
            cls._ASYNC_CLIENTS[io_loop] = instance
            return instance