Future _handleSingleRequest()

in lib/src/server.dart [196:240]
39 lines of code
9 McCabe index (conditional complexity)

  Future _handleSingleRequest(request) async {
    try {
      _validateRequest(request);

      var name = request['method'];
      var method = _methods[name];
      method ??= _tryFallbacks;

      Object? result;
      if (method is ZeroArgumentFunction) {
        if (request.containsKey('params')) {
          throw RpcException.invalidParams('No parameters are allowed for '
              'method "$name".');
        }
        result = await method();
      } else {
        result = await method(Parameters(name, request['params']));
      }

      // A request without an id is a notification, which should not be sent a
      // response, even if one is generated on the server.
      if (!request.containsKey('id')) return null;

      return {'jsonrpc': '2.0', 'result': result, 'id': request['id']};
    } catch (error, stackTrace) {
      if (error is RpcException) {
        if (error.code == error_code.INVALID_REQUEST ||
            request.containsKey('id')) {
          return error.serialize(request);
        } else {
          onUnhandledError?.call(error, stackTrace);
          return null;
        }
      } else if (!request.containsKey('id')) {
        onUnhandledError?.call(error, stackTrace);
        return null;
      }
      final chain = Chain.forTrace(stackTrace);
      return RpcException(error_code.SERVER_ERROR, getErrorMessage(error),
          data: {
            'full': '$error',
            'stack': '$chain',
          }).serialize(request);
    }
  }