loadData method

@override FutureOr<Map<String, dynamic>> loadData()

Implementation

@override
FutureOr<Map<String, dynamic>> loadData() async {
  String content;
  try {
    final uri = Uri.base.resolve(url);
    final request = await _httpClient.getUrl(uri);
    headers.forEach((k, v) {
      request.headers.add(k, v);
    });
    final response = await request.close();
    if (response.statusCode != HttpStatus.ok) {
      await response.drain([]);
      throw GeoJsonLoadException(
          "Error requesting GeoJSON from $url: HTTP ${response.statusCode}");
    }
    content = await response.transform(utf8.decoder).join();
  } on Exception catch (e) {
    if (e is GeoJsonLoadException) rethrow;
    throw GeoJsonLoadException("Error downloading GeoJSON from $url: $e");
  }

  dynamic data;
  try {
    data = json.decode(content);
  } on Exception catch (e) {
    throw GeoJsonLoadException("Error parsing GeoJSON: $e");
  }

  _validateGeoJson(data);
  return data;
}