PHP nested output cache example-PHP Tutorial-php.cn

PHP nested output cache example

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Release： 2023-03-18 14:48:01

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How does PHP implement nested output caching? This article mainly introduces PHP nested output caching code examples, and uses the ob series functions to solve nested output caching examples. I hope to be helpful.

PHP’s output cache can be nested. Use ob_get_level() to output the nesting level.
The test found that the output results are different under the cli and the browser (PHP5.4).

The manual instructions are as follows:

ob_get_level() will always return 0 inside a destructor. 
This happens because the garbage collection for output buffers has already done before the destructor is called

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It is also very simple to output correctly:

ob_end_clean();
echo ob_get_level(); //0

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Back to the topic:

ob_end_clean();
 
ob_start();
echo &#39;php1&#39;;//此处并不会在页面中输出
$a = ob_get_level();
$b = ob_get_contents();//获得缓存结果,赋予变量
ob_clean();
 
ob_start();
echo &#39;php2&#39;;//此处并不会在页面中输出
$c = ob_get_level();
$d = ob_get_contents();//获得缓存结果,赋予变量
ob_clean();
 
ob_start();
echo &#39;php3&#39;;//此处并不会在页面中输出
$e = ob_get_level();
$f = ob_get_contents();//获得缓存结果,赋予变量
ob_clean();
 
echo &#39;level:&#39;.$a.&#39;,ouput:&#39;.$b.&#39;<br>&#39;;
echo &#39;level:&#39;.$c.&#39;,ouput:&#39;.$d.&#39;<br>&#39;;
echo &#39;level:&#39;.$e.&#39;,ouput:&#39;.$f.&#39;<br>&#39;;

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The results are as follows:

level:1,ouput:php1
level:2,ouput:php2
level:3,ouput:php3

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Of course, when you turn off a certain level of buffering, test as follows:

ob_end_clean();
 
ob_start();
echo &#39;php1&#39;;
$a = ob_get_level();
$b = ob_get_contents();
ob_clean();
 
ob_start();
echo &#39;php2&#39;;
$c = ob_get_level();
$d = ob_get_contents();
ob_end_clean();  //清空缓存并关闭缓存
 
ob_start();
echo &#39;php3&#39;;
$e = ob_get_level();
$f = ob_get_contents();
ob_clean();
 
echo &#39;level:&#39;.$a.&#39;,ouput:&#39;.$b.&#39;<br>&#39;;
echo &#39;level:&#39;.$c.&#39;,ouput:&#39;.$d.&#39;<br>&#39;;
echo &#39;level:&#39;.$e.&#39;,ouput:&#39;.$f.&#39;<br>&#39;;

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The results are as follows:

level:1,ouput:php1
level:2,ouput:php2
level:2,ouput:php3

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