Migrating from Post Meta to Custom Post Types

There are, as it happens, a lot of ways to do this. This is a way that I tested and it works, but it’s not the final way I did things. That said, this does work and, if you’re not on a shared server, is just fine.

The Concept

I have (roughly) 2200 posts in a custom post type (post_type_characters). Each of those posts has a post meta field for actors (lezchars_actor). The content of the post meta is an array of text fields, that looks something like this:

Array(
    [0] => "Caity Lotz",
    [1] => " Jacqueline MacInnes Wood (Arrow 1x01 only)"
)

I wanted to take the post meta and split it into a post for each actor, however I wanted to remove any comments in parenthesis. I also wanted to change the content of lezchars_actor to be the IDs of the new actors pages.

Did I mention I had 2200 posts? And some actors were there multiple times? And I didn’t want to make a lot of duplicate posts.

The Code

If you want to do this with PHP, it’ll look something like this:

<?php
/*
Plugin Name: Post Bulk Update
Description: Change all the actors to Taxonomy
*/

add_action('wp','post_bulk_update_queers');

function post_bulk_update_queers(){
	$char_queery = new WP_Query( array(
		'post_type'              => 'post_type_characters',
		'posts_per_page'         => '3000',
	) );

	if ( $char_queery->have_posts() ) {
		while ( $char_queery->have_posts() ) {
			$char_queery->the_post();
			$the_ID = get_the_ID();

			// Get the post meta for actor:
			$postmeta_actors = get_post_meta( $the_ID, 'lezchars_actor', true );
			if ( !is_array ( $postmeta_actors ) ) {
				$postmeta_actors = array( get_post_meta( $the_ID, 'lezchars_actor', true ) );
			}
			
			if ( !empty( $postmeta_actors ) ) {

				$posts_actors = array();
				// Create posts if needed:
				foreach ( $postmeta_actors as $actor ) {
					// Make sure the ID isn't numeric as that means we did this...
					if ( !is_numeric( $actor ) ) {

						// Remove content in parens...
						$actor = preg_replace( '/\([^)]+\)/', '', $actor );

						$already_post = get_page_by_path( sanitize_title( $actor ), OBJECT, 'post_type_actors' );
						if ( !( $already_post ) ) {
							// Create post object
							$my_post_args = array(
								'post_title'    => wp_strip_all_tags( $actor ),
								'post_status'   => 'publish',
								'post_author'   => 1,
								'post_type'     => 'post_type_actors',
							);
	
							// Insert the post into the database
							$my_post = wp_insert_post( $my_post_args );
							
							// add post to array
							array_push( $posts_actors, $my_post );
						} else {
							array_push( $posts_actors, $already_post->ID );
						}
					}
				}
				
				// Change the post meta to be numbers
				update_post_meta( $the_ID, 'lezchars_actor', $posts_actors );
			}
		}
	}
}

Notes

The reason this really works is this:

$already_post = get_page_by_path( sanitize_title( $actor ), OBJECT, 'post_type_actors' );

That actually checks if the page with the slug already exists and if so, uses it to edit the post meta.

If you don’t have robust hosting, or you have a lot of posts, you’ll need to edit the $char_queery like this:

	$char_queery = new WP_Query( array(
		'post_type'              => 'post_type_characters',
		'posts_per_page'         => '300',
		'offset'                 => '0',
	) );

Run it once, bump the offset from 0 to 300, and repeat until you get through all your posts.

Ipstenu (Mika Epstein)

I’m Mika (aka Ipstenu) and I’m complicated. I’ve been on the net since the days of dedicated terminals and Novation CAT modems and solved Missionaries and Cannibals (or Goats and Cabbages) before I was six, and blog about WordPress and technical/computer things at Half Elf on Tech.

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