http_request.dart

/// HttpRequest:
/// Dart の基本の Request クラスを HttpRequestProtocol で拡張したもの
class HttpRequest extends Request {
  final HttpRequestProtocol service;

  HttpRequest(this.service)
    : super(
        service.method.value,
        Uri.parse('${service.baseUrl}${service.path}${service.queryParameters}')
    );
  
  @override
  Map<String, String> get headers => this.service.headers;

  @override
  String get body => json.encode(this.service.parameters);

  @override
  Uint8List get bodyBytes {
    if (service.contentEncoding == ContentEncoding.url) {
      final queryParameters = Uri(queryParameters: service.parameters);
      List<int> bodyBytes = utf8.encode(queryParameters.query);

      return bodyBytes;
    } else {
      final encodedBody = Utf8Codec().encode(body);
      return Uint8List.fromList(encodedBody);
    }
  }

  @override
  MediaType get _contentType {
    var contentType = headers['content-type'];
    if (contentType == null) return null;
    return new MediaType.parse(contentType);
  }
}