Include Custom Comment Fields in Privacy Exports and Erasures

// Comment meta key => label in the export.
$wpide_comment_meta_fields = array(
    'phone'  => 'Phone number',
    'rating' => 'Rating',
);

$wpide_comment_ids_for = function ( $email, $page ) {
    return get_comments( array(
        'author_email' => $email,
        'number'       => 100,
        'paged'        => max( 1, (int) $page ),
        'fields'       => 'ids',
        'status'       => 'all',
        'orderby'      => 'comment_ID',
        'order'        => 'ASC',
    ) );
};

add_filter( 'wp_privacy_personal_data_exporters', function ( $exporters ) use ( $wpide_comment_meta_fields, $wpide_comment_ids_for ) {
    $exporters['wpide-comment-meta'] = array(
        'exporter_friendly_name' => 'Extra comment fields',
        'callback'               => function ( $email, $page = 1 ) use ( $wpide_comment_meta_fields, $wpide_comment_ids_for ) {
            $ids   = $wpide_comment_ids_for( $email, $page );
            $items = array();

            foreach ( $ids as $id ) {
                $data = array();
                foreach ( $wpide_comment_meta_fields as $key => $label ) {
                    $value = get_comment_meta( $id, $key, true );
                    if ( '' !== $value ) {
                        $data[] = array( 'name' => $label, 'value' => is_scalar( $value ) ? (string) $value : wp_json_encode( $value ) );
                    }
                }
                if ( $data ) {
                    $items[] = array( 'group_id' => 'comments', 'group_label' => 'Comments', 'item_id' => 'comment-' . $id, 'data' => $data );
                }
            }

            return array( 'data' => $items, 'done' => count( $ids ) < 100 );
        },
    );

    return $exporters;
} );

add_filter( 'wp_privacy_personal_data_erasers', function ( $erasers ) use ( $wpide_comment_meta_fields, $wpide_comment_ids_for ) {
    $erasers['wpide-comment-meta'] = array(
        'eraser_friendly_name' => 'Extra comment fields',
        'callback'             => function ( $email, $page = 1 ) use ( $wpide_comment_meta_fields, $wpide_comment_ids_for ) {
            $ids     = $wpide_comment_ids_for( $email, $page );
            $removed = false;

            foreach ( $ids as $id ) {
                foreach ( array_keys( $wpide_comment_meta_fields ) as $key ) {
                    $removed = delete_comment_meta( $id, $key ) || $removed;
                }
            }

            return array( 'items_removed' => $removed, 'items_retained' => false, 'messages' => array(), 'done' => count( $ids ) < 100 );
        },
    );

    return $erasers;
} );