JSON-RPC Async Request How-to?

Remoting SDK
1

Hi there,

what would be your recommendation to implement the async calls on the RO Services via json-rpc? Is there some built-in feature for that?

Thank you!

Best regards

2

You can use _Async/_AsyncEx services - they are designed for async calls

3

If I execute this request

{
	"version": "1.1",
	"method": "HelloWorldService_Async.Invoke_GetHelloWorld",
	"params": {}
}

I am getting an error

{
    "version": "1.1",
    "error": {
        "name": "JsonRPCError",
        "code": "1",
        "message": "Class factory for interface HelloWorldService_Async not found"
    }
}

What class factory should I take?

How can I check if an answer is received? Colud you write the JSON-RPC request for that?

Thanks!

4

pls review sample: json_async.zip (108.1 KB)

Untitled
Untitled.png891×551 50 KB

5

thanks for the sample. There is no problem to call the async service in a delphi application. How do I call the service async in a REST tool, e.g. in Postman?

6

you can’t call service method in async mode directly.

if you like to launch something async from 3rd party client like Postman, you have to add new special methods:

  • one method will launch something in background thread
  • [optionally] second method will check state of execution, i.e. completed or still running
  • [optionally] third method will return result of execution, if it is required
7

okay, that is what I wanted to hear. Thank you for your time and help!

8

I am trying to implement an async approach

function TService.Invoke_ServiceMethod(const AValue: string): string;
var
  TokenID: string;
begin
  TokenID := GUIDToString(Session.SessionID);

  Session.Values[AValue] := 'Some Session Value';

  FLongTask := TTask.Create(
   procedure()
  var
    anonSession: TROSession;
  begin
      anonSession := Session;
      Sleep(10000);
       anonSession.Values['hello'] := 'world';
        fClassFactory.TimeoutSession(ClientID);
    end);
  FLongTask.Start;

  Result := TokenID;
end;


initialization
  fClassFactory := TROPerClientClassFactory.Create(__ServiceName, Create_Service, TRORTTIInvoker, 691200);

finalization
  UnRegisterClassFactory((fClassFactory as IROClassFactory));
  fClassFactory := nil;
  1. What do you think about this approach?
  2. Do you have a recommendation for a better solution?
  3. Why does Session.Values[AValue] := ‘Some Session Value’ work? And anonSession.Values[‘hello’] := ‘world’ does’nt work! :frowning:

Thank you!!!

9

this one may not work correctly because, your session can be expired already.

You can try another code. this one will allow also call methods from another service, like

  sid := Session.SessionID;
  FLongTask := TTask.Create(
    procedure()
    var
      service: TSessionTypesService;
      instance: IUnknown;
      objactivation:IROObjectActivation;
    begin
      Sleep(10000);
      Service := TService.Create(nil);
      instance := Service as IUnknown;
      if Supports(Service, IROObjectActivation, objactivation) then begin
        objactivation.OnActivate(sid, nil);
        objactivation := nil;
      end;
      Service.Session.Values['hello'] := 'world';
      if Supports(instance, IROObjectActivation, objactivation) then begin
        objactivation.OnDeactivate(sid);
        objactivation := nil;
      end;
      instance := nil;
    end
    );
    FLongTask.Start;