public void SaveRequest(RequestParam requestModel)
{
var allRequest = GetAllRequest()?.ToList();
var existingRequest = allRequest?.FirstOrDefault(node => node.Guid == requestModel.Guid);
allRequest = allRequest ?? new List <RequestParam> {
requestModel
};
if (existingRequest != null)
{
RequestParam.CopyObjectDetails(requestModel, existingRequest);
}
var json = JsonConvert.SerializeObject(allRequest);
File.WriteAllText(fileName, json);
}