Feature/network interface

[wssgcg1213]

Close #172

• 判断是否为 Kraken 内部发起的请求, 以及区分 contextId
• interceptor 需要传入 Kraken widget 实例参数
• 测试通过

[wssgcg1213]

DEMO

class CustomHttpClientInterceptor implements HttpClientInterceptor {
  DateTime _startTime;
  DateTime _endTime;

  @override
  Future<HttpClientRequest> beforeRequest(HttpClientRequest request) {
    request.headers.set('x-foo', 'bar');
    print('beforeRequest, request headers: ${request.headers}');
    if (request.uri.path == '/posts/1') {
      _startTime = DateTime.now();
    }
    return null;
  }

  @override
  Future<HttpClientResponse> afterResponse(HttpClientRequest request, HttpClientResponse response) {
    print('afterResponse, response headers: ${response.headers}');
    if (request.uri.path == '/posts/1') {
      _endTime = DateTime.now();
      print('/posts/1 cost: ${_endTime.millisecondsSinceEpoch - _startTime.millisecondsSinceEpoch}ms');
    }
    return null;
  }

  @override
  Future<HttpClientResponse> shouldInterceptRequest(HttpClientRequest request) async {
    if (request.uri.path == '/posts/1') {
      // Direct output string, transform to stream.
      String replaced = '{ "foo": "bar" }';
      Uint8List data = Uint8List.fromList(replaced.codeUnits);
      Stream<Uint8List> stream = Stream<Uint8List>.value(data);
      return SimpleHttpClientResponse('text/html', 'utf8', stream, responseHeaders: { 'x-kraken': 'hey', 'a': '1' });
    }
    return null;
  }
}


void main() {
  runApp(Kraken(
    viewportWidth: viewportSize.width - queryData.padding.horizontal,
    viewportHeight: viewportSize.height - appBar.preferredSize.height - queryData.padding.vertical,
    // bundlePath: 'assets/bundle.js',
    // bundleURL: 'https://kraken.oss-cn-hangzhou.aliyuncs.com/demo/richtext.js',
    bundleContent: '''
      fetch('https://jsonplaceholder.typicode.com/posts/1')
        .then(function(response) {
          return response.json();
        })
        .then(function(data) {
          // This is the object from API.
          console.log('LOG:', data);
        })
        .catch(err => {
          console.error('error:', err);
        });
    ''',
    httpClientInterceptor: CustomHttpClientInterceptor(),
  ));
}

===>