强制 netcat 立即发送消息(无缓冲) [英] Force netcat to send messages immediately (without buffering)

问题描述

我正在使用python脚本通过标准print()参数生成数据.然后，脚本的输出应发送到localhost tcp socket 9999.

I'm using a python script to generate data using standard print() arguments. The output from the script should then be sent to localhost tcp socket 9999.

python script.py | nc -lk 9999

在客户端，我正在侦听localhost tcp套接字9999，以验证一切正常.

On the client side I'm listening to localhost tcp socket 9999 to verify everything is working fine.

nc localhost 9999

是的，它正在工作.但是看起来nc在发送消息之前正在缓冲一些消息.结果，我在客户端遇到了巨大的延迟，这对于我的应用程序是不可接受的:我需要尽快获得数据.

And yes, it's working. But it looks like nc is buffering some messages before sending them. As a result, I get huge delays on the client side, which is not acceptable for my application: I need the data asap.

是否可以禁用缓冲区?

我注意到，如果我发送更多消息，则延迟会减少.但是，这并不是我真正的解决方案.

I noticed that if I send more messages, the delay decreases. However, this isn't really a solution for me.

推荐答案

您可以使用 stdbuf 命令:

stdbuf -o0 python script.py | stdbuf -i0 nc -lk 9999

或python的-u Unbuffered选项:

or the -u Unbuffered option for python:

python -u script.py | stdbuf -i0  nc -lk 9999

I/O缓冲是由libc处理的，除非程序自己明确地对其进行处理. stdbuf 影响该行为.进一步阅读 man stdbuf .

I/O buffering is, unless a program explicitly handles it on it's own, handled by the libc. stdbuf influences that behaviour. Further reading man stdbuf.

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