url static method

String url(String name, { Map<String, Object?> params = const <String, Object?>{}, Map<String, Object?> query = const <String, Object?>{}, })

the path of the route named name, with its {params} filled in. a param value is url encoded. query is added as the query string. an unknown name or a missing param throws an ArgumentError.

Route.url('users.show', params: <String, Object>{'id': 5});
// /users/5

Implementation

static String url(
  String name, {
  Map<String, Object?> params = const <String, Object?>{},
  Map<String, Object?> query = const <String, Object?>{},
}) {
  RouteData? data = Route()._byName()[name];
  if (data == null) {
    throw ArgumentError.value(name, 'name', 'No route has this name');
  }
  Set<String> used = <String>{};
  List<String> parts = <String>[];
  for (String part in data.path.split('/')) {
    if (!part.startsWith('{') || !part.endsWith('}')) {
      parts.add(part);
      continue;
    }
    bool rest = part.endsWith('*}');
    bool optional = part.endsWith('?}');
    String param = part
        .substring(1, part.length - 1)
        .replaceAll('*', '')
        .replaceAll('?', '');
    Object? value = params[param];
    used.add(param);
    if (value == null) {
      if (optional) continue;
      throw ArgumentError(
        'Route "$name" (${data.path}) needs the param "$param".',
      );
    }
    parts.add(
      rest
          ? '$value'.split('/').map(Uri.encodeComponent).join('/')
          : Uri.encodeComponent('$value'),
    );
  }
  for (String key in params.keys) {
    if (!used.contains(key)) {
      throw ArgumentError(
        'Route "$name" (${data.path}) has no param "$key". '
        'Use query: for the query string.',
      );
    }
  }
  String path = parts.join('/');
  if (path.isEmpty) path = '/';
  if (query.isEmpty) return path;
  Map<String, String> values = <String, String>{
    for (MapEntry<String, Object?> entry in query.entries)
      if (entry.value != null) entry.key: '${entry.value}',
  };
  if (values.isEmpty) return path;
  return '$path?${Uri(queryParameters: values).query}';
}