Is Page or Subpage WP Function

Derek Herman — Sat, 21 Mar 2009 12:47:13 +0000

Have you ever wanted to know if the page you’re on is a child of a certain page because you needed to know that information in order to add a snippet of code to the sidebar or remove something or whatever you had planned but you tried and just couldn’t figure out a solution that was simple and easy to maintain? Well, here is a piece of code that will do just that. I use this very code all over the place, on pretty much every project I do. The concept is simple. I need to know more than if the is_page(‘portfolio’); I need to know if this is_page_or_sub(‘portfolio’);

This is pretty much the same function as is_page(), it lets you pass in a page ID or slug, your choice, but the only real difference is that it goes beyond a single page and looks for a family relationship. The function will return true for all children and grandchildren of the page id or slug you pass in. For example, you want to show two different sidebars, one for normal content and one for the portfolio section. You would use this function to do that. First, copy and paste this code into your functions.php and then take a look at the usage example below.

EDIT:
You can get an updated version if this function and as a plugin if you got to here.

The Function

//If is page or subpage of $my_page, works with both ID or name.
if (!function_exists('is_page_or_sub')) {
    function is_page_or_sub($my_page) {
        global $post, $wpdb;
	$grand_parent = $wpdb->get_var("SELECT post_parent FROM $wpdb->posts WHERE ID = '".$post->post_parent."' AND post_type = 'page'");
	// If you pass in a string, get the page ID of $my_page to use below
	if (is_numeric($my_page)==false) {
            $my_page = $wpdb->get_var("SELECT ID FROM $wpdb->posts WHERE post_name = '".$my_page."' AND post_type = 'page'");
	}
	// If this is $my_page or the child or grandchild of $my_page return true 
	if ( is_page($my_page) || $post->post_parent == $my_page || $grand_parent == $my_page ) {
	    return true;
	} 
	// Else return false
        return false;
    }
}

Sample Usage

if (is_page_or_sub('portfolio')) { 
    DISPLAY PORTFOLIO SIDEBAR
} else {
    DISPLAY REGULAR SIDEBAR
}

If you have any question feel free to comment below. Have fun taking over the internet one WordPress blog at a time.

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Valen Designs grants you a nonexclusive copyright license to use all programming code examples from which you can generate similar function tailored to your own specific needs.

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Valen Designs » PHP

Is Page or Subpage WP Function

The Function

Sample Usage

Donations

Disclaimer