Hook runs twice

[feniks502]

Hello!

The only hook into 'trash' in a module runs twice, by itself, as it seems.

The following code outputs:

• Session: Hooked 1 times on abcd
• Session: Hooked 2 times on abcd

on the admin side when one page is deleted from it's delete tab.

And it's no matter 'addHookBefore', 'addHookaAfter' or 'addHook' method is used.

Why?!

private $i = 0;

public function init() {

	$this->pages->addHookBefore('trash', $this, 'test');

}

public function test($event) {

	$page = $event->arguments('page');

	$this->i++;
	$this->message("Hooked {$this->i} times on {$page->title}");

}

[Sebii]

Hi,

I could reproduce this in current dev 3.0.16. .   Pages::trash seems to be executed twice.
Is this still up to date for you? Maybe anyone else has a hint on what is wrong with it?

Greetings

[feniks502]

Hi,

I could reproduce this in current dev 3.0.16. .   Pages::trash seems to be executed twice.

Is this still up to date for you? Maybe anyone else has a hint on what is wrong with it?

Greetings

I had found nothing about this.

Just updated my installation to dev 3.0.17 and still have two messages instead of one.

It is critical for me, because  I have write current amount of 'Pages' within the structure like 'Parent(1) -> Parent(1.1) + Parent(1.2) +Parent(1.3) , ... -> Pages' to the 'Parent(1)' each time it is changed, so I don't know any other way, than hook into 'save', 'trash', 'delete', 'move' methods.

Particularly, concerning the 'trash' or 'delete' methods, I have to hook into them before execution to find '$page->parent->parent', to which data will be written (as you see after that it is impossible), but with 'trash' method my 'beforeHook' saves '$page->parent->parent' to a module class property correctly, and then it is get overwritten immediately, so it looks like 'addHookBefore' adds hook before and after.

[adrian]

Try Soma's suggestion about using Pages::trashed

https://processwire.com/talk/topic/5918-function-getting-run-twice/

[Sebii]

Hi thanks for that hint. I can only try it out later.

For feniks, this might not help as I understood, as he needs the page before it is trashed, but maybe it could work if you change your hook method (test above) with a check if the page is trashed? If there are really two different calls like Soma suggested, it should be one before actually trashed and in the second call of the modified page before save(?).
Maybe you get to try it out before me:

$page = $event->arguments('page');
if($page->isTrash()) return; //should only happen on the second call(?)

However I did not fully understand your use-case fully. Depending on what you want, it might be much easier to just count the children where you need them in Parent(1) or if you know the parent(s) you want the count for, you could also do it easier I guess:

// e.g. just:
$page->numChildren;
// in the template, or outside e.g:
$pages->count("has_parent=/locationOf/Parent");

Hope this helps.

[Niku]

I ran into this same issue with triggers 'trash' and 'restore'. I was trying to do stuff before page is trashed/restored. I saw weird behavior but it took a good while until I understood triggers were being triggered multiple times per request.

My use case: I need to communicate with REST API when page changes. Running triggers multiple times is an issue as it leads to unexpected results. I had to go around the issue with class properties, but I don't think that should be the case. I assumed addHookBefore('Pages::restore'...) would be run once.

[MarkE]

I know it's a long time since the last post, but this still seems to be an issue in 3.0.123. It's easily avoided by setting a flag to prevent repeats (see below), but is it a bug or a side-effect of some intended behaviour?

wire()->addHookBefore('Pages::trash', function ($event) {
    $p = $event->arguments(0);
    if ($this->skip != $p->id) {
        $this->skip = $p->id;

 

[Robin S]

For anyone wanting to trace how it is that Pages::trash is called twice...

Pages::trash (first call) calls PagesTrash::trash, and when the "save" argument is true (as it is when trashing via the admin) then Pages:save is called, which calls PagesEditor::save.

And if that saved page is in the trash then Pages::trash is called (second call) with the "save" argument false.

As to whether this second Pages::trash call is necessary and correct, I don't know.

Best thing is to hook Pages::trashed as suggested above - this method only fires if the page is successfully trashed, which is probably what is wanted in most cases.

[MarkE]

1 hour ago, Robin S said:

(second call) with the "save" argument false.

Aha! So a better way to avoid the hook being called twice would be to test for the 'save' argument.

1 hour ago, Robin S said:

Best thing is to hook Pages::trashed as suggested above

In my case I can't use the trashed hook as I need to access the parent of the page being trashed, which is too late if it has been trashed.

[MarkE]

26 minutes ago, MarkE said:

test for the 'save' argument.

Except that, in the 'before' hook, the test is is_null() because the default 'true' value has not been set. The second time, the argument will be 'false', which is not null ? 

[Robin S]

48 minutes ago, MarkE said:

In my case I can't use the trashed hook as I need to access the parent of the page being trashed, which is too late if it has been trashed.

Yeah, makes me wonder if it would have been better if the Pages::trashed method was called immediately before saving the trashed page rather than after. Maybe Ryan has a good reason for doing it that way.

I still think it's better to hook after Pages::trashed if you want to know for sure which pages are trashed because when hooking Pages::trash there are still instances where the trashing can fail. For example, there might be another Pages::trash hook in a module that deliberately prevents trashing of particular pages.

If you hook Pages::trashed you can parse the parent page ID (and some other info) from the name of the page in the trash:

$pages->addHookAfter('trashed', function(HookEvent $event) {
	$page = $event->arguments(0);
	$pages = $event->object;
	/* @var PagesTrash $trasher */
	$trasher = $pages->trasher();
	$name_info = $trasher->parseTrashPageName($page->name);
	if(!empty($name_info['parent_id'])) {
		$parent = $pages($name_info['parent_id']);
		// ...
	}
});