Finding out which Wordpress template is used for a page from admin page

Question

I'm trying to retrieve the filename/path of template used on the 'Edit Page'-page in the Dashboard.

Similar to what wp-includes/template-loader.php (source) does on the front end: finding out which template to render.

Unfortunately, expressions like is_front_page() - which Wordpress' template-loader.php uses to find out if it should use get_front_page_template() - don't work correctly on the admin page. Which is to be expected because those expression use the global $wp_query object, and not the current query.

What I've tried so far:

Running a post loop inside the admin page

$args = array(
    'p' => get_the_ID(),
    'post_type' => 'any'
);

$query = new \WP_Query($args);

if ( $query->have_posts() ) : while ( $query->have_posts() ) : $query->the_post(); ?>

    <?= the_title(); ?><br>
    Is front page: <?= is_front_page() ? 'true' : 'false' ?>

<?php endwhile; endif; ?>

Displays:

Home

Is front page: false

Using get_post_meta

<?= get_post_meta(get_the_ID(), '_wp_page_template', true); ?>

Displays:

default

...which would be the same for front-page.php on Home and page.php on another default page, so this doesn't help me.

In short

What I'm trying to get is front-page.php when I'm editing my 'Home' page. Or custom-template.php when I'm editing some page with the custom template selected. Or about-page.php when I'm editing a page called 'About'. How to get the correct filename or path?

Answer 1

If your specific problem is with the home page, you could use a combination of get_page_template() and comparing the edited page's ID with get_option('page_on_front') (see WordPress option reference). There's also an option, show_on_front, which indicates whether the front page shows posts or a static page.

Maybe this helps? I don't know if there are other edge cases where a different template will be used...

Answer 2

Use get_page_template():

<?php echo realpath(get_page_template()); ?> 

It outputs something like /foo/bar/baz/wp-content/themes/your-theme/{page-template}.php

You can choose not to use realpath() and just get the template name.