In a recent project, I had the need to get an array of all of the pages on a site that were using a particular page template. It turns out that this is really just an extension of any other type of meta query I could run, but you need to know that the meta field storing the info for the page template is in _wp_page_template.
I found a few examples of this using WP Query, but decided to write a quick little function using the get_pages function instead because it seemed cleaner for this use case then having to cleanup WP Query.
The function looks like this:
function get_page_by_template($template = '') {
$args = array(
'meta_key' => '_wp_page_template',
'meta_value' => $template
);
return get_pages($args);
}
In my case, using get_pages instead of the WP_Query class make sense because of what I’ve trying to find, but I’d recommend checking out this article on the difference between WP_Query, get_posts, and get_pages for further reading on when you might want to use a specific strategy.