PHP缓冲区ob_flush()与flush() [英] PHP buffer ob_flush() vs. flush()

问题描述

ob_flush()和flush()有什么区别?为什么必须同时调用两者?

What's the difference between ob_flush() and flush() and why must I call both?

ob_flush()参考说:

此函数将发送输出缓冲区的内容(如果有).

This function will send the contents of the output buffer (if any).

flush()参考说:

刷新PHP的写缓冲区以及PHP正在使用的任何后端(CGI，Web服务器等).

Flushes the write buffers of PHP and whatever backend PHP is using (CGI, a web server, etc).

但是，它继续说:

[it]可能无法覆盖您的Web服务器的缓冲方案……

[it] may not be able to override the buffering scheme of your web server…

所以，在我看来，我可以一直使用ob_flush().但是，当我这样做时，会得到奇怪的结果.有人可以简单地解释一下这是怎么回事吗?

So, seems to me that I could just use ob_flush() all of the time. However, I get strange results when I do that. Could someone explain in simple terms what's going on here?

推荐答案

ob_flush发送应用程序启动的缓冲区.任何PHP脚本中都可能有多个嵌套的ob_start(). ob_flush将当前内容传递到上层.

ob_flush sends an application-initiated buffer. There may be multiple nested ob_start()'s in any PHP script. ob_flush passes the current content to the upper layer.

PHP本身(可能会自行决定)是否缓冲输出.这取决于后端.但是通常FastCGI自己有一个套接字缓冲区.因此，还需要调用flush()，以将当前内容发送到Web服务器.

PHP itself might (at its own discretion) buffer output. This depends on the back-end. But usually FastCGI has a socket buffer on its own. Therefore flush() needs to be invoked as well to send the current content to the web server.

现在，Web服务器本身可能实现了另一种缓冲方案(mod_deflate或内容过滤器)，您对此没有影响.但这很少见，因为需要对其进行专门配置.

And now the web server might itself implement another buffering scheme (mod_deflate or content filter), which you have no influence over. But this is seldom, as it needs to be configured specifically.

无论如何，请同时使用两者.

Anyway, use both.

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