http.py 文件源码

def expires(delta):
    """
    Outputs an `Expires` header for `delta` from now. 
    `delta` is a `timedelta` object or a number of seconds.
    """
    if isinstance(delta, (int, long)):
        delta = datetime.timedelta(seconds=delta)
    date_obj = datetime.datetime.utcnow() + delta
    web.header('Expires', net.httpdate(date_obj))