Adding custom fields (post meta) before/during wp_insert_post()

Question

Our code base has a ton of logic that executes as the post is inserted/created. However, some of that logic depends on custom post meta. The only way I know of to add post meta to a new post is like so:

$post_id = wp_insert_post($post_obj);
add_post_meta($post_id, 'key', "value");

However, this means that the post meta is not present when hooks on post insertion happen.

Is there any way to set up or include post meta as part of $post_obj?

I tried making up new properties of the post object with $post_obj->custom_key = 'value' but it didn't seem to actually end up in the database. The only thing I can think of is to hijack an existing property of the post object that I'm not using, like menu_order, and store some information there. That's an ugly hack.

Answer 1

You can hook your function to the wp_insert_post action hook:

add_action( 'wp_insert_post', 'wpse128767_add_meta' );
function wpse128767_add_meta( $post_id ) {
    add_post_meta( $post_id, 'key', 'value' );
}

To make sure your metadata has been added before any other insert hooks run, give it a higher priority:

add_action( 'wp_insert_post', 'wpse128767_add_meta', 1 );

By default add_action() uses a priority of 10; the lower the number, the earlier it runs.

Answer 2

Here is a solution.

//Your args to Gather post data.
$args = array(
    'post_title'    => 'My post',
    'post_content'  => 'This is my post.',
    'post_status'   => 'publish',
    'post_author'   => 1,
);


//Retrieve Id back after new post is made.
$post_id = wp_insert_post( $args, true );

//Check for errors, before updating meta fields
 if (is_wp_error($post_id)):
        $errors = $post_id->get_error_messages();
        foreach ($errors as $error):
            //log errors
            echo $error;
        endforeach;
 else:

   //If updating WP meta
   update_post_meta( $post_id, meta_key1, 'add this');
   update_post_meta( $post_id, meta_key2, 'add something');

   //if updating ACF meta
   //update_field( 'meta_key1', 'add this', $post_id );
   //update_field( 'meta_key2', 'add something', $post_id );
 
 endif;