Process/iterate through all posts in a post type

wp-process-post-type.php

<?php

/*
This function will loop through all posts matching a filter, allowing you to make some edits to them with PHP.

To begin just visit your site ending with /?FojVDY83

Important: To avoid re-processing the same post infinitely, you need to make sure the meta_query will not match the same post after it has been processed. This is done below by checking if the meta key "status" exists or not.

*/
function rs_FojVDY83_process_posts() {
	$args = array(
		'post_type'      => 'media-request',
		'meta_query'     => array(
			array(
				'key'     => 'status',
				'compare' => 'NOT EXISTS',
			),
		),
		'posts_per_page' => 20,
	);
	
	$query = new WP_Query( $args );
	
	if ( $query->have_posts() ) {
		while( $query->have_posts() ): $query->the_post();
			echo 'Updating post: <a href="' . esc_attr( get_edit_post_link( get_the_ID() ) ) . '" target="_blank">' . get_the_title() . '</a>';
			echo "<br>";
			
			// Change the post title if the "subject" field is set in ACF
			$subject = get_field( 'subject', get_the_ID() );
			
			if ( $subject ) {
				$args = array(
					'ID'         => get_the_ID(),
					'post_title' => $subject,
				);
				wp_update_post( $args );
			}
			
			// Update the custom status field, this also prevents the same post from being processed a second time.
			update_field( 'status', 'Imported', get_the_ID() );
		
		endwhile;
		
		// Reload the page to continue processing while we have results
		?>
		<script type="text/javascript">setTimeout(function () {
				window.location.href = window.location.href;
			}, 500);</script>
		<?php
		
	}else{
		
		// When we've processed everything, just say we're done
		echo 'done';
		
	}
	
	exit;
}

if ( isset( $_REQUEST['FojVDY83'] ) ) {
	add_action( 'init', 'rs_FojVDY83_process_posts' );
}