I'm looking for a solution to "clone or copy or associate" custom fields data to custom taxonomies.

example: Custom field "location" should copy data of that posts custom field to Custom Taxonomy "location"

There is a plugin which Converts custom fields to custom taxonomies on demand, http://wordpress.org/extend/plugins/custom-field-taxonomies/ but I would need it's function in cron... automatically on daily basis....

Any solution counts, to adopt this plugin work in cron or a simple code to accomplish this function


1 Answer 1


Here is a simple plugin with the convert function from the plugin you linked and a simple WordPress cron setup to run daily just make sure you change CUSTOM_FIELD_KEY and TAXONOMY_NAME to the actual values

Plugin Name: wpse62432
Plugin URI: http://en.bainternet.info
Description: Answer to http://wordpress.stackexchange.com/questions/62432/copy-clone-associate-custom-field-to-custom-taxonomy
Version: 1.0
Author: bainternet
Author URI: http://en.bainternet.info

function Location_convert( $cf_key, $taxonomy ) {
    global $wpdb;

    $rows = $wpdb->get_results( $wpdb->prepare( "
        SELECT post_id, GROUP_CONCAT( meta_value ) as terms
        FROM $wpdb->postmeta
        WHERE meta_key = %s
        GROUP BY post_id
    ", $cf_key ) );

    foreach ( $rows as $row ) {
        $post_id = $row->post_id;
        $terms = explode( ',', $row->terms );
        $terms = (array) apply_filters( 'cft_terms_pre', $terms, $post_id );

        // Convert raw values to term ids
        foreach ( $terms as $i => $term_name ) {
            $term_name = trim( $term_name );

            if ( empty( $term_name ) )

            $term = get_term_by( 'name', $term_name, $taxonomy, ARRAY_A );

            if ( !$term ) {
                $term = wp_insert_term( $term_name, $taxonomy );

                if ( is_wp_error( $term ) ) {
                    self::$errors[$term_name] = $term->get_error_message();

            $terms[ $i ] = (int) $term['term_id'];

        wp_set_object_terms( $row->post_id, $terms, $taxonomy, true );

    return $wpdb->query( $wpdb->prepare( "DELETE FROM $wpdb->postmeta WHERE meta_key = %s", $cf_key ) );

add_action('location_daily_event', 'do_this_daily');

function location_activation() {
    if ( !wp_next_scheduled( 'location_daily_event' ) ) {
        wp_schedule_event( current_time( 'timestamp' ), 'daily', 'location_daily_event');
add_action('wp', 'location_activation');

function do_this_daily() {
  • Thank you for your quick response! ... Will try it.. can I change "daily" to "hourly".. it would be also easier for testing.. If I need more than one field to be converted, should I just copy/paste the whole code or just the last part "add_action..." and just change the CUSTOM_FIELD_KEY','TAXONOMY_NAME'?
    – Miha
    Aug 20, 2012 at 23:04
  • yes you can change to hourly, as for another field simply add in the do_this_daily function another call to ` location_convert()` with the second field key.
    – Bainternet
    Aug 21, 2012 at 6:24

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