将超时设置为python套接字连接recv方法

Question

我正在尝试编写一个简单的http服务器。我希望它对Connection: keep-alive标头起作用，所以我想确保connection.recv()会超时。我尝试了socket.settimeout(timeout)方法，但是即使收到数据，它也会在timeout时间后关闭连接。我想要的是这样的：

while True:
    try:
        #start to wait for timeout seconds
        request = conn.recv(256, timeout)
        process()
        #if there is no keep-alive header end the operation
        if "keep-alive" not in request:
            conn.close()
            break
        else:
            #if there was a keep alive header start getting the data
            continue
    except:
        #this means timeout seconds passed after recv() was called
        conn.close()
        break

做这件事的最好方法是什么？