Auto assign author to new posts with wp_insert_post_data

Question

I need to make the default author for all new posts be already selected but leave existing posts unmodified.

So since the default post status is "draft" i thought to only do this if the post is a draft like so:

add_filter( 'wp_insert_post_data' , 'update_author', '99', 2 );

function update_author($data , $postarr) {
if ($postarr['post_status'] == 'draft') {
    $data['post_author'] = 45;
 }
  return $data;
}

But then it never runs, so i tried the other way around. Do it when it isn't "published" but then it runs for all new and existing posts...

add_filter( 'wp_insert_post_data' , 'update_author', '99', 2 );

function update_author($data , $postarr) {      
 if ($postarr['post_status'] != 'published') {       
    $data['post_author'] = 45;
 }
  return $data;
}

What am i missing here?

Answer 1

to know if it's a new post, you juste need to read the value of $postarr["ID"] :

$postType = "post";

add_filter("wp_insert_post_data" . $postType, function ($data, $postarr) {

    if (0 === $postarr["ID"]) { // it's a new post

        $data["post_author"] = 45;

    }


    return $data;


}, 10, 2);