Get field always retruns null in wp_insert_post hook.

• RajatDas

• January 25, 2022 at 3:45 am

I was wondering if there was a way to set a thumbnail when creating a post. With a hard-coded image url in the wp_insert_post hook, I was able to set the thumbnail.

The custom field (of type text) does not work when passed as a URL. The issue occurs with or without the post_id.

get_field('device_image_url') returns the url when used inside a single post.

function set_post_thumbnail_when_created( $post_id, $post, $update ) {
	require_once( ABSPATH . 'wp-admin/includes/media.php' );
	require_once( ABSPATH . 'wp-admin/includes/file.php' );
	require_once( ABSPATH . 'wp-admin/includes/image.php' );
	if ( wp_is_post_revision( $post_id ) ) {
		return;
	}
	if ( ! $update ) {
		//$url  = "https://fdn2.gsmarena.com/vv/bigpic/xiaomi-poco-m4-pro-5g.jpg";
		$url  = get_field( "device_image_url" );
		$desc = "image description";
		
		$image = media_sideload_image( $url, $post_id, $desc, 'id' );
		set_post_thumbnail( $post_id, $image );
	}
}

add_action( 'wp_insert_post', 'set_post_thumbnail_when_created', 10, 3 );

I’d appreciate your help with this.

• John Huebner

• January 25, 2022 at 2:04 pm

When getting a field during the save process you must supply the post ID to get the value from or it will not return a value.

$url  = get_field( "device_image_url", $post_id );