WordPress: WooCommerce Product Attributes - Bulk Modifier ( from custom meta attributes to taxonomy attributes)

woo-product-attributes-bulk-modifier.php

<?php
/**
 * Plugin Name:   WooPAM: Woo Product Attributes Modifier
 * Description:   Bulk update 'custom meta product attributes' to 'taxonomy product attributes' in WooCommerce. Supports the GET variables, like: woopam_mode=run&woopam_from_attribute_meta=colour&woopam_to_attribute_tax=pa_colour&woopam_keep_attribute_meta&woopam_posts_per_page=10&woopam_paged=0&woopam_post_type=product&woopam_post_status=any. WARNING: Backup DB first!!!
 * Plugin Author: birgire
 * Author URI:    https://github.com/birgire
 * Plugin URI:	  https://gist.github.com/birgire/0ed300ae4436fcaf508c
 * Version:       1.0.0
 * License:       GPL2+
 * Text Domain:   woopam
 * Requires PHP:  5.4
 */
 
 /*
  *---------
  * Support:
  *---------
  * If this helped your project and saved you some time, you can support the developement here:
  *
  * https://www.buymeacoffee.com/birgire
  *
  * Thanks.
  *
  *---------------
  * Usage Example: 
  *---------------
  *
  *     To change all custom product meta attributes "color" to "pa_color" products taxonomy (where pa_ is a WooCommerce auto-added prefix),  we can run:
  * 
  *         https://example.com/?woopam_mode=run&woopam_from_attribute_meta=color&woopam_to_attribute_tax=pa_color&woopam_keep_attribute_meta=1&woopam_posts_per_page=100&woopam_paged=0&woopam_post_type=product&woopam_post_status=any
  *
  *     REMEMBER: Create the product taxonomy beforehand here (without pa_ prefixing it yourself):
  *
  *        https://example.com/wp-admin/edit.php?post_type=product&page=product_attributes
  *
  *     WARNING: Remember to backup your database first!!!
  * 
  *-----------
  * CHANGELOG:
  *-----------
  *
  * 2021-12-13 v1.0.0 Overhaul (Work: 5 hours)
  * 
  *------
  * TODO:
  *------
  *
  * - Split into more smaller functions.
  * - Add tests.
  * - Add more documentation.
  * - Look into UI.
  */
  
add_action( 'template_redirect', function() {

	// Activate product attribute modification (only available for admins).
	if ( ! current_user_can( 'manage_options' ) || 'run' !== filter_input( INPUT_GET, 'woopam_mode' ) ) {
		return;
	}

	// User input.
	$keep_attribute_meta = filter_input( INPUT_GET, 'woopam_keep_attribute_meta', FILTER_VALIDATE_BOOLEAN );
	$from_attribute_meta = filter_input( INPUT_GET, 'woopam_from_attribute_meta', FILTER_SANITIZE_STRING );
	$to_attribute_tax    = filter_input( INPUT_GET, 'woopam_to_attribute_tax', FILTER_SANITIZE_STRING );
	$post_type           = filter_input( INPUT_GET, 'woopam_post_type', FILTER_SANITIZE_STRING );
	$post_status         = filter_input( INPUT_GET, 'woopam_post_status', FILTER_SANITIZE_STRING );
	$posts_per_page      = filter_input( INPUT_GET, 'woopam_posts_per_page', FILTER_SANITIZE_NUMBER_INT );
	$paged 	             = filter_input( INPUT_GET, 'woopam_paged', FILTER_SANITIZE_NUMBER_INT );

	// Default values.
	if ( empty( $posts_per_page ) ) {
		$posts_per_page = 10;
	}

	if ( empty( $paged ) ) {
		$paged = 1;
	}

	if ( empty( $post_type ) ) {
		$post_type = 'product';
	}

	if ( empty( $keep_attribute_meta ) ) {
		$keep_attribute_meta = false;
	}

	if ( empty( $post_status ) ) {
		$post_status = 'any';
	}
	
	if ( empty( $from_attribute_meta ) || empty( $to_attribute_tax ) ) {
		wp_die( esc_html__( 'Oh, rembember that the "from_attribute_meta" and "to_attribute_tax" variable must be set!', 'woopam' ) );
	}
	
	$meta_key = '_product_attributes';

	// Fetch products with product attributes:
	$args = array(
		'post_type'      => sanitize_key( $post_type ), 
		'fields'         => 'ids', 
		'posts_per_page' => (int) $posts_per_page,
		'paged'		 => absint ( $paged ),
		'meta_key'       => $meta_key,
		'post_status'    => sanitize_key( $post_status ),
	);
	$post_ids = get_posts( $args );
	
	$total = 0;
	$total_modified = 0;

	$msg = esc_html__( "Bulk update 'custom meta product attributes' to 'taxonomy product attributes'", 'woopam' );

	printf( 
		'<h1>%s</h1>%s<ul>',
		$msg,
		esc_html__( 'START', 'woopam' )
	);

	foreach ( (array) $post_ids as $post_id ) {		

		$total++;

		$meta                 = get_post_meta( $post_id, $meta_key, true );
		$product_needs_update = false;

		foreach ( (array) $meta as $key => $terms ) {

			// Locate our meta attribute.
			if ( $from_attribute_meta === $terms['name'] ) {
				$product_needs_update = true;
				$tmp                  = explode( '|', $terms['value'] );			
				$product_terms        = array();
				
				foreach ( (array) $tmp as $term ) {
					$product_terms[] = $term;
				}

				// Remove the product meta attribute:
				if ( ! $keep_attribute_meta ) {
					unset( $meta[$key] );		
				}
				
				// Add it again as product taxonomy attribute:
				$meta["{$to_attribute_tax}"] = array( 
					'name'         => "{$to_attribute_tax}",
					'value' 	   => '',
					'position'     => $terms['position'], 
					'is_visible'   => $terms['is_visible'], 
					'is_variation' => $terms['is_variation'], 
					'is_taxonomy'  => 1, 
				);	
				
			} // end if
		} // end foreach

		echo '<li>';

		if ( $product_needs_update ) {
		
			// Assign terms to the post (create them if they don't exists).
			$term_taxonomy_ids = wp_set_object_terms( $post_id, $product_terms, $to_attribute_tax, false );
			if ( is_wp_error( $term_taxonomy_ids ) ) {
				$msg = sprintf( 
					esc_html__( 'Error! Terms couldn\'t be set for product id: %d and WP error description: "%s" and product taxonomy slug: "%s"', 'woopam' ),
					(int) $post_id,
					esc_html( $term_taxonomy_ids->get_error_code() ), 
					esc_html( $to_attribute_tax )
				);
				printf( '<strong>%s</strong><br/>', $msg );

			} else {
				update_post_meta( $post_id, $meta_key, $meta );
				$total_modified++;
				$msg = sprintf(
					esc_html__( 'Success! The taxonomy post attributes were set for product id: %d', 'woopam' ),
					(int) $post_id
				);
				printf( '<strong>%s</strong><br/>', $msg );
			}
		} else {
			$msg = sprintf(
				esc_html__( 'Nothing to do here! No product attributes were set for product id: %d', 'woopam' ),
				$post_id
			);
			printf( '%s<br/>', $msg );
		}
		echo '</li>';
		
	} // end foreach post.
	echo '</ul><br/>';

	printf( 
		esc_html__( 'Total products checked: %d', 'woopam' ),
		(int) $total
	);
	
	echo '<br/>';
	
	printf(
		esc_html__( 'Total modified products: %d', 'woopam' ),
		(int) $total_modified
	);
	
	echo '<br/>';
	echo '<br/>';
	
	die( esc_html__( 'END', 'woopam' ) );
} );

To also preserv the variations, I added this code after the row "update_post_meta( $post_id, $meta_key, $meta );":

$args = array(
    'post_type' => 'product_variation',
    'post_status' => 'any',
    'post_parent' => $post_id,
    'fields' => 'ids',
    'posts_per_page' => -1
);
$variations = get_children( $args );
if ( is_array( $variations ) && count( $variations ) > 0 ) {
    foreach ( $variations as $variation_id ) {
        $term = get_post_meta( $variation_id, 'attribute_' . strtolower( $from_attribute_meta ), true );
        delete_post_meta( $variation_id, 'attribute_' . strtolower( $from_attribute_meta ) );
        update_post_meta( $variation_id, 'attribute_' . $to_attribute_tax, strtolower( $term ) );
    }
    $default_attributes = get_post_meta( $post_id, '_default_attributes', true );
    if ( is_array( $default_attributes ) ) {
        foreach ( $default_attributes as $key => $term) {
            if ( $key == strtolower( $from_attribute_meta ) ) {
                unset( $default_attributes[$key] );
                $default_attributes[$to_attribute_tax] = strtolower( $term );
            }
        }
        update_post_meta( $post_id, '_default_attributes',  $default_attributes );
    }
}

Thanks for your feedback @smoovo and @realweb11

Hey @birgire thank you so much for this code!

I've made some adjustments that refine variations handling, since the attribute name get slugified and my terms had some special chars in them I had problems with both the import method and the @realweb11 code above.

Line 105

/* Get only products that shares the target attribute */
'meta_query' => [
    [
        'key' => $meta_key,
        'compare' => 'LIKE',
        'value' => sprintf('"%s"', $from_attribute_meta)
    ]
],

Line 129

/* Selected target attribute by slug to avoid issues with spaces and special characters */
if ( $from_attribute_meta === $key ) {

Line 172

/* Added code from @realweb11 with the correction of the slug for the new term (used sanitize_title instead of strtolower) */
$args = array(
    'post_type' => 'product_variation',
    'post_status' => 'any',
    'post_parent' => $post_id,
    'fields' => 'ids',
    'posts_per_page' => -1
);

$variations = get_children( $args );

if ( is_array( $variations ) && count( $variations ) > 0 ) {
    foreach ( $variations as $variation_id ) {
        $term = get_post_meta( $variation_id, 'attribute_' . strtolower( $from_attribute_meta ), true );
        delete_post_meta( $variation_id, 'attribute_' . strtolower( $from_attribute_meta ) );
        update_post_meta( $variation_id, 'attribute_' . $to_attribute_tax, sanitize_title( $term ) );
    }

    $default_attributes = get_post_meta( $post_id, '_default_attributes', true );

    if ( is_array( $default_attributes ) ) {
        foreach ( $default_attributes as $key => $term) {
            if ( $key == strtolower( $from_attribute_meta ) ) {
                unset( $default_attributes[$key] );
                $default_attributes[$to_attribute_tax] = sanitize_title( $term );
            }
        }
        update_post_meta( $post_id, '_default_attributes',  $default_attributes );
    }
}

Note: With these modifications, it's crucial that the parameter woopam_from_attribute_meta is the slug of the starting attribute.
Thank you again for your gist!

Awesome, thank you for sharing @emmelemme