I need to run a function when a particular post or page is loaded. Is there any hook that lets me check whether a post is being displayed during page load ?

  • public or admin side/facing?
    – kaiser
    Commented Oct 16, 2012 at 10:48
  • 1
    For front end. Basically I want it to trigger only when a particular single custom post type is displayed. Commented Oct 16, 2012 at 10:52

3 Answers 3


You can use the wp hook and check the global $wp_query object or any conditional.

add_action( 'wp', 'wpse69369_special_thingy' );
function wpse69369_special_thingy()
    if (
        'special_cpt' === get_post_type()
        AND is_singular()
        return print "Yo World!";

    return printf(
        '<p>Nothing to see here! Check the object!<br /></p><pre>%s</pre>',
        var_export( $GLOBALS['wp_query'], true )

See: wp in codex.wordpress.org and wp in developer.wordpress.org

  • can you please tell me when does 'wp' hook run? Commented Oct 16, 2012 at 11:07
  • A) It runs before after_setup_theme and setup_theme, so it's only accessible for plugins B) inside WP :: main(), which is called from within wp-settings.php.
    – kaiser
    Commented Oct 16, 2012 at 11:19
  • 1
    @kaiser Doesn't the wp hook fire after the after_setup_theme hook and right before template_redirect therefore making wp accessible by themes as well as plugins? (just to clarify?)
    – Adam
    Commented Oct 17, 2012 at 6:18

Use template_redirect which is the action hook that fires before rendering the template;

add_action('template_redirect', 'hooker');
function hooker(){
    //I load just before selecting and rendering the template to screen
  • @PoulomiNag No problem, glad you found your answer above. Though I think one small note is that wp runs after the after_theme_setup hook, so its not just accessible by plugins, making it safe to use in themes.
    – Adam
    Commented Oct 17, 2012 at 6:21
  • I just checked and yes ; wp runs after after_theme_setup. But I need it for my plugin. So wp as well as template_redirect both work fine for me. Wish I could accept two answers here! :) Commented Oct 17, 2012 at 7:33
  • That's ok, not necessary to accept both, just wanted to clarify the order in which they fire. Making sure I'm not going crazy you know. Good luck with your plugin...
    – Adam
    Commented Oct 17, 2012 at 7:42
  • 4
    +1 for function name pun
    – MJHd
    Commented Feb 28, 2020 at 21:56

I've quite often used the following to load in custom meta boxes on pages (rather than custom posts).


    function how_we_do_it_meta() {

        if ( $_SERVER['SCRIPT_NAME'] == '/wp-admin/post.php' ) {

            $post_id = $_GET['post'] ? $_GET['post'] : $_POST['post_ID'];
            $template_file = get_post_meta($post_id,'_wp_page_template',TRUE);

            if ($template_file == 'page-how-we-do-it.php') {

                add_meta_box('how_we_do_it_who-meta', 'Who we work with...', 'how_we_do_it_who', 'page', 'normal', 'high');

                add_action('save_post', 'save_how_we_do_it_meta');

  • 1
    Thanks Darronz. But I need some hook to work at the front end during a page load. Any ideas? Commented Oct 16, 2012 at 7:07
  • If you changed the above to add_action('init', // etc) then it'll work on the page load rather than only in the admin section.
    – darronz
    Commented Oct 16, 2012 at 7:19
  • 2
    @darronz And then you need to check ! is_admin() inside, because the init hook runs on both sides.
    – kaiser
    Commented Oct 16, 2012 at 11:20

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