connect method

@override Future<void> connect(String? url, TransferFormat transferFormat)

Implementation

@override
Future<void> connect(String? url, TransferFormat transferFormat) async {
  assert(!isStringEmpty(url));

  _url = url;

  _logger?.finest("(LongPolling transport) Connecting");

  if (transferFormat == TransferFormat.Binary) {
    throw new GeneralError(
        "Binary protocols via Long Polling Transport is not supported.");
  }

  final pollOptions = SignalRHttpRequest(
      abortSignal: _pollAbort.signal,
      headers: MessageHeaders(),
      timeout: 100000);

  final token = await _getAccessToken();
  _updateHeaderToken(pollOptions, token);

  // Make initial long polling request
  // Server uses first long polling request to finish initializing connection and it returns without data
  final pollUrl = "$_url&_=${DateTime.now()}";
  _logger?.finest("(LongPolling transport) polling: $pollUrl");
  final response = await _httpClient.get(pollUrl, options: pollOptions);
  if (response.statusCode != 200) {
    _logger?.severe(
        "(LongPolling transport) Unexpected response code: ${response.statusCode}");

    // Mark running as false so that the poll immediately ends and runs the close logic
    _closeError = HttpError(response.statusText ?? "", response.statusCode);
    _running = false;
  } else {
    _running = true;
  }

  _receiving = poll(_url, pollOptions);
}