update_post_meta() whenever custom post type is updated

Question

I need the following functionality. Whenever my custom post type is updated or saved I need to overwrite certain custom post metas.

I need to make sure this only affects posts of the post type 'VA_LISTING_PTYPE' and posts that have the have for the 'meta_key' => 'featured-cat' the 'meta_value' => 1

The code I'm using at the moment is the following (not working)

//Remove urls from free listings
function remove_url_free_post( $post_id ) {

$slug = 'VA_LISTING_PTYPE',
    if ( $slug != $_POST['post_type'] ) {
    return;
    }

    $meta_values = get_post_meta( $post_id, 'featured-cat', true );
if ( $meta_values != 1 ) {
    return;
    }

    update_post_meta($post_id, 'website', '');
    update_post_meta($post_id, 'twitter', '');
    update_post_meta($post_id, 'facebook', '');

}
add_action('save_post', 'remove_url_free_post');

I also tried different action hooks like pre_post_update coming from this answer

I just can't seem to get it working. The only really ugly fix that is working for me right now is this one:

//Remove urls from free listings
function remove_url_free_post() {
    //Fetches all the listings that have featured cat which equals free listing for us
    $r = new WP_Query( 
    array( 
        'post_type' => VA_LISTING_PTYPE,
        'no_found_rows' => true,
        'meta_key' => 'featured-cat',
        'meta_value' => 1
    ) );
    if ( $r->have_posts() ) :
    while ( $r->have_posts() ) : $r->the_post();

    //removes the website, twitter and facebook
    $post_id3 = get_the_ID();
    update_post_meta($post_id3, 'website', '');
    update_post_meta($post_id3, 'twitter', '');
    update_post_meta($post_id3, 'facebook', '');

    endwhile;
    endif;
}
//Not ideal at all as called everytime, save_post not working as intended
add_action('wp_footer', 'remove_url_free_post');

Answer 1

You're right to use 'save_post' action hook.

Try this:

<?php

add_action('save_post', 'some_function');

function some_function($post_id)
{
        if(get_post_type($post_id) != "VA_LISTING_PTYPE")
        return;
    $meta_value = get_post_meta( $post_id, 'featured-cat', true );
    if($meta_value != 1)
        return;
    update_post_meta($post_id, 'website', '');
    update_post_meta($post_id, 'twitter', '');
    update_post_meta($post_id, 'facebook', '');
}

if you're on Wordpress 3.7 or higher, you can use it this way:

add_action('save_post_VA_LISTING_PTYPE', 'some_function');

function some_function($post_id)
{
    $meta_value = get_post_meta( $post_id, 'featured-cat', true );
    if($meta_value != 1)
        return;
    update_post_meta($post_id, 'website', '');
    update_post_meta($post_id, 'twitter', '');
    update_post_meta($post_id, 'facebook', '');
}

I hope it work with you.