class UrlEncode

class UrlEncode extends ProcessPluginBase {
    
    /**
     * {@inheritdoc}
     */
    public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
        // Only apply to a full URL.
        if (is_string($value) && strpos($value, '://') > 0) {
            // URL encode everything after the hostname.
            $parsed_url = parse_url($value);
            // Fail on seriously malformed URLs.
            if ($parsed_url === FALSE) {
                throw new MigrateException("Value '{$value}' is not a valid URL");
            }
            // Iterate over specific pieces of the URL raw URL encoding each one.
            $url_parts_to_encode = [
                'path',
                'query',
                'fragment',
            ];
            foreach ($parsed_url as $parsed_url_key => $parsed_url_value) {
                if (in_array($parsed_url_key, $url_parts_to_encode)) {
                    // urlencode() would convert spaces to + signs.
                    $urlencoded_parsed_url_value = rawurlencode($parsed_url_value);
                    // Restore special characters depending on which part of the URL this is.
                    switch ($parsed_url_key) {
                        case 'query':
                            $urlencoded_parsed_url_value = str_replace('%26', '&', $urlencoded_parsed_url_value);
                            break;
                        case 'path':
                            $urlencoded_parsed_url_value = str_replace('%2F', '/', $urlencoded_parsed_url_value);
                            break;
                    }
                    $parsed_url[$parsed_url_key] = $urlencoded_parsed_url_value;
                }
            }
            $value = (string) Uri::fromParts($parsed_url);
        }
        return $value;
    }

}