Retrieving grandparent

[jacmaes 211]

I'm working on a photographer's site. My tree is organized as such:

Home

--Photography

----Abstractions
------Photo 1 (photo on its own page; template: portfolio_image)
------Photo 2
----Animals
----Signs
----etc.

--Places:

----United States (template: country)
------New Jersey (template: state)
--------Newark (template:city)
--------Ringwood
--------etc.
------New York
 

In each photo's page (e.g. "Photo 1"), I have a page reference field name "city" where I can select the city (e.g. "Newark").

Now in "Places", I'm trying to retrieve all the photos in each country, for example all pics taken in the United States. I need to find the grandparent of "city", i.e. the country where that city belongs to,  but "city.has_parent=$country" or "city.parent.parent=$country" don't work:

<?php
$foreach ($page->children as $country):
	$photos_by_country = $pages->find("template=portfolio_image, city.has_parent=$country");

	foreach ($photos_by_country as $photos):
		echo $photos->title;
	endforeach;

endforeach;
?>

 

What's the selector for "the grandparent of the city field" is…? Thanks for your help.

[bernhard 3,292]

Dont know if that's the best option, but you could use two selectors:

$cities = $pages->findIDs("template=city, parent=yourcity");
$photos = $pages->find([
  'template' => 'photo',
  'city' => $cities,
]);

Another option would be a saveReady hook that populates the country on each photo save. And I'm quite sure there are even better solutions  

[jacmaes 211]

Thanks a lot @bernhard. You put me on the right track. I just changed "parent=yourcity" to "has_parent=$country". For posterity, here are the two selectors in my case:

 

$cities = $pages->findIDs("template=city, has_parent=$country");
$photos = $pages->find([
      'template' => 'portfolio_image',
      'city' => $cities,
    ]);

 

[bernhard 3,292]

You could also use sub-selectors: https://processwire.com/docs/selectors/#sub-selectors

[jacmaes 211]

That's why I tried first, but has_parent does not seem to work as a sub-selector.

[bernhard 3,292]

$photos = $pages->find("template=portfolio_image, city=[template=city, has_parent=$country]");

This does not work?

[jacmaes 211]

I've tried and double-checked, but no, for some reason, "has_parent" does not seem to work in this case, even if I manually replace $country with a valid parent id.  "Parent" does work as expected, but it's of no use here. A bug, or a limitation with "has_parent" maybe?