subscribeToSSE static method

Stream<SSEModel> subscribeToSSE(String url, String token)

Implementation

static Stream<SSEModel> subscribeToSSE(String url, String token) {
  //Regex to be used
  var lineRegex = RegExp(r'^([^:]*)(?::)?(?: )?(.*)?$');
  //Creating a instance of the SSEModel
  var currentSSEModel = SSEModel(data: '', id: '', event: '');
  // ignore: close_sinks
  StreamController<SSEModel> streamController = new StreamController();
  print("--SUBSCRIBING TO SSE---");
  while (true) {
    try {
      _client = http.Client();
      var request = new http.Request("GET", Uri.parse(url));
      //Adding headers to the request
      request.headers["Cache-Control"] = "no-cache";
      request.headers["Accept"] = "text/event-stream";
      request.headers["Cookie"] = token;
      Future<http.StreamedResponse> response = _client.send(request);

      //Listening to the response as a stream
      response.asStream().listen((data) {
        //Applying transforms and listening to it
        data.stream
          ..transform(Utf8Decoder())
              .transform(LineSplitter())
              .listen((dataLine) {
            if (dataLine.isEmpty) {
              //This means that the complete event set has been read.
              //We then add the event to the stream
              streamController.add(currentSSEModel);
              currentSSEModel = SSEModel(data: '', id: '', event: '');
              return;
            }
            //Get the match of each line through the regex
            Match match = lineRegex.firstMatch(dataLine)!;
            var field = match.group(1);
            if (field!.isEmpty) {
              return;
            }
            var value = '';
            if (field == 'data') {
              //If the field is data, we get the data through the substring
              value = dataLine.substring(
                5,
              );
            } else {
              value = match.group(2) ?? '';
            }
            switch (field) {
              case 'event':
                currentSSEModel.event = value;
                break;
              case 'data':
                currentSSEModel.data =
                    (currentSSEModel.data ?? '') + value + '\n';
                break;
              case 'id':
                currentSSEModel.id = value;
                break;
              case 'retry':
                break;
            }
          });
      });
    } catch (e) {
      print('---ERROR---');
      print(e);
      streamController.add(SSEModel(data: '', id: '', event: ''));
    }

    Future.delayed(Duration(seconds: 1), () {});
    return streamController.stream;
  }
}