Reply To: Custom fields on woocommerce product variations

• rchipka

• March 17, 2018 at 5:49 am

WooCommerce Product Variations are *all* saved via a single POST request.

To differentiate between product variation fields, WooCommerce names each field field_name[variation_id] so that it is accessible as $_POST['field_name'][$variation_id].

ACF field data is located in $_POST['acf'][...] and can only have one of each field.

ACF’s acf()->input->save_post( $post_id ) method uses $_POST['acf'] data, so it cannot contain fields for another variation.

We need to allow duplicate ACF fields to exist within a single <form> without having them overwrite each other’s value within $_POST['acf'].

We can achieve this by renaming the field name prefix acf[...] to acf_varation[variation_id][...] and then set $_POST['acf'] to $_POST['acf_varation'][$variation_id] when saving.

$GLOBALS['wc_loop_variation_id'] = null;

function is_field_group_for_variation($field_group, $variation_data, $variation_post) {
	return (preg_match( '/Variation/i', $field_group['title'] ) == true);
}

add_action( 'woocommerce_product_after_variable_attributes', function( $loop_index, $variation_data, $variation_post ) {
		$GLOBALS['wc_loop_variation_id'] = $variation_post->ID;

		foreach ( acf_get_field_groups() as $field_group ) {
			if ( is_field_group_for_variation( $field_group, $variation_data, $variation_post ) ) {
				acf_render_fields( $variation_post->ID, acf_get_fields( $field_group ) );
			}
		}

		$GLOBALS['wc_loop_variation_id'] = null;
	}, 10, 3 );

add_action( 'woocommerce_save_product_variation', function( $variation_id, $loop_index ) {
		if ( !isset( $_POST['acf_variation'][$variation_id] ) ) {
			return;
		}

		$_POST['acf'] = $_POST['acf_variation'][$variation_id];

		acf()->input->save_post( $variation_id );
	}, 10, 2 );

add_filter( 'acf/prepare_field', function ( $field ) {
		if ( !$GLOBALS['wc_loop_variation_id'] ) {
			return $field;
		}

		$field['name'] = preg_replace( '/^acf\[/', 'acf_variation[' . $GLOBALS['wc_loop_variation_id'] . '][', $field['name'] );

		return $field;
	}, 10, 1);