public HttpResponseMessage Operations([FromBody] IEnumerable <string> woids, string op)
        {
            var messages = new List <ErrorMessage>();

            if (op == WorkflowOperation.Delete.ToString())
            {
                foreach (var o in woids)
                {
                    var resp = TasksService.DeleteWorkflow(new ControlWorkflowRequest
                    {
                        WorkflowOid = o
                    });

                    if (resp.Message != "OK")
                    {
                        messages.Add(new ErrorMessage {
                            Id = o, Message = resp.Message
                        });
                    }
                }
            }
            if (op == WorkflowOperation.Restart.ToString())
            {
                foreach (var o in woids)
                {
                    var resp = TasksService.ReStartWorkflow(new ReStartWorkflowRequest
                    {
                        OldWorkflowId = o
                    });

                    if (resp.Message != "OK")
                    {
                        messages.Add(new ErrorMessage {
                            Id = o, Message = resp.Message
                        });
                    }
                }
            }
            if (op == WorkflowOperation.Terminate.ToString())
            {
                foreach (var o in woids)
                {
                    var resp = TasksService.CancelWorkflow(new ControlWorkflowRequest
                    {
                        WorkflowOid = o
                    });

                    if (resp.Message != "OK")
                    {
                        messages.Add(new ErrorMessage {
                            Id = o, Message = resp.Message
                        });
                    }
                }
            }

            var json = JsonConvert.SerializeObject(
                messages,
                Formatting.Indented,
                new JsonSerializerSettings {
                ContractResolver = new CamelCasePropertyNamesContractResolver()
            });

            var result = Request.CreateResponse(HttpStatusCode.OK);

            result.Content = new StringContent(json, Encoding.UTF8, "text/plain");
            return(result);
        }