I have seen several answers on object destruction order, and all point out that order is not guaranteed. Since I cannot control the order, I would like to invoke a function after all objects have been destroyed.
register_shutdown_function is invoked prior to object destruction, thus not an option. I have looked at tricks like set_error_handler using the object so it is invoked "late", but that is not sufficient.
Some background on the problem, this is a complex CMS with dozens of separate files for routes (view) layer. There is a common boot include, but not a common one run at shutdown. I am using APCu object caching through a common inherited base class, and need to make sure an object is purged. It is possible that for any two instances of the same object created during a page load, one might want to purge itself, and the other might want to cache itself. Obviously purge trumps all else, so I need to call apc_delete on a global set of cache keys to purge one all __destruct()'ion is complete.
我见过几个关于对象销毁订单的答案，并且都指出订单无法保证。 由于我无法控制顺序，我想在所有对象被销毁后调用一个函数。
在对象销毁之前调用register_shutdown_function，因此不是一个选项。 我已经使用该对象查看了set_error_handler这样的技巧，因此它被“迟到”调用，但这还不够。
问题的一些背景，这是一个复杂的CMS ，包含许多用于路径（视图）图层的单独文件。 有一个常见的启动包括，但不是在关机时运行的常见启动。 我通过公共继承的基类使用APCu对象缓存，并且需要确保清除对象。 对于在页面加载期间创建的同一对象的任何两个实例，可能希望清除自身，而另一个可能想要自我缓存。 显然purge胜过其他所有，所以我需要在一组全局缓存键上调用apc_delete来清除一个__destruct（）'离子完成。
As I said in my comment above, the mixed state of multiple object instances sounds like a design flaw. I think you always want all instances of an object to be the latest, or at least not touch the cache if they aren't. I would think your caching and/or object loading layer could handle this.
To answer your underlying question, I wrote a script to test PHP's shutdown sequence:
微信扫一扫<?php /* Adapted from https://evertpot.com/160/ */
ob_start(
function($buffer) {
return $buffer . "output buffer flushed
";
}
);
$empty = function() {
return true;
};
$close = function() {
echo "session close
";
return true;
};
$write = function() {
echo "session write
";
return true;
};
session_set_save_handler($empty, $close, $empty, $write, $empty, $empty);
session_start();
register_shutdown_function(
function() {
echo "register_shutdown_function
";
}
);
class MyClass {
function __destruct() {
echo "object destructor
";
}
}
$myObject = new MyClass;
The output:
register_shutdown_function
object destructor
output buffer flushed
session write
session close
It seems the flush of output buffering and session write/close are 2 places where you know all of your objects have been destroyed. (This also assumes you're not using the newer form of session_set_save_handler that can register itself as a shutdown function.)