Run a function on all posts

Question

I have a function where I am counting letters in a title and adding that _product_meta_title key, everything is working fine when I am adding a new product but I have 500 products that don't have this key. So I need to run my function on all posts once.

function save_post_title_length_meta( $post_id, $post, $update ) {

/*
 * In production code, $slug should be set only once in the plugin,
 * preferably as a class property, rather than in each function that needs it.
 */
$post_type = get_post_type($post_id);

$title = get_post_field( 'post_name', $post_id );

$title_length = strlen( $title );


// If this isn't a 'product' post, don't update it.
if ( "product" != $post_type ) return;

// - Update the post's metadata.

if ( $title ) {
    update_post_meta( $post_id, '_product_title_length', $title_length );
}}

I am using this action to run my function

add_action( 'save_post', 'save_post_title_length_meta', 10, 3 );

How to run it so it will affect all my existing post on wp load, init? Any recommendations on where to start?

Thanks

Answer 1

Rather than hooking into init or wp_load, here is a snippet you can drop into functions.php or on a theme file. I put it behind a $_GET so that you can only hit it once and when you are ready. Something like https://domain.com/page/?update_post_meta

// Hide it from the public
if(isset($_GET['update_post_meta'])){

  // Let's query all of the product post_type.
  $product_args = array(
    'post_type' => 'product',
    'posts_per_page' => -1
  );
  $product_query = new WP_Query($product_args);

  while( $product_query->have_posts()): $product_query->the_post();

    $title_length = strlen($post->post_name);

    // - Update the post's metadata.
    if ( $post->post_name ) {
      update_post_meta( $post->ID, '_product_title_length', $title_length );
    }

  endwhile; 

}

If you want to run this on specific posts you have not edited already, you can update the $product_args array to have a date range in it.

Hope this helps!!