mORMot Open Source

fenix

Member

Registered: 2015-08-02

Posts: 3

RttiInstanceType.GetMethod is generated exception

Hello,

I am testing mormot (mORMotNightlyBuild 2015-08-01).
If apply the RttiInstanceType.GetMethod to execute the method is generated exception of more 30% of the requisitions when executed with more of instance.

  //... The class name and method are sent via parameters. Ctxt.InputString['NameClasseController'] ...
  RttiInstanceType := Contexto.FindType('CfopController.TCfopController') as TRttiInstanceType;
  return := TExtjsVO(RttiInstanceType.GetMethod('Consult').Invoke(RttiInstanceType.MetaclassType, MyParameters).AsObject);
 //... 

But if execute without the RttiInstanceType is not generated exception.

  return := TExtjsVO(TCfopController.Consult('id=1', '1', True));

Please This is a problem in rtti or mormot?

Thanks

Last edited by fenix (2015-08-02 15:52:13)

ab

Administrator

From: France

Registered: 2010-06-21

Posts: 14,660

Website

Re: RttiInstanceType.GetMethod is generated exception

I do not understand what your code is doing.
Sounds to me like RTTI abuse.
If you have the type information, transtype the instance to its final type, using "as" or "is", and call the Consult method.
Use class types, and not RTTI here.

I guess there is no problem in mORMot or in RTTI, but in how you are using the RTTI.

fenix

Member

Registered: 2015-08-02

Posts: 3

Re: RttiInstanceType.GetMethod is generated exception

Thanks for your reply.

I do not know what the class and the method will depend on the parameter.
http://localhost:777/restSF/ObjectJson/?NameClassController=CfopController.TCfopController&NameMethod=Consult&Parameters=id=1|1|True

procedure TServiceServer.ObjectJson(Ctxt: TSQLRestServerURIContext);
var
  Context: TRttiContext;
  RttiInstanceType: TRttiInstanceType;
  parameters: TArrayParameters;
  pNameClassController: String;
  pNameMethod: String;
  pParameters: String;
  return: TExtjsVO;
begin
  try
    if UrlDecodeNeedParameters(Ctxt.Parameters, 'NameClassController') then
    begin
      pNameClassController := Ctxt.InputString['NameClassController'];
      pNameMethod := Ctxt.InputString['NameMethod'];
      pParameters := Ctxt.InputString['Parameters'];
    end;
    Parameters := MountParameters(pParameters);
    RttiInstanceType := Context.FindType(pNameClassController) as TRttiInstanceType;
    return := TExtjsVO(RttiInstanceType.GetMethod(pNameMethod).Invoke(RttiInstanceType.MetaclassType, Parameters).AsObject);
    if Assigned(return ) then
    begin
      Ctxt.Returns(ObjectToJson(return , []));
      FreeAndNil(return);
    end;
    Ctxt.success;
  finally
    Contexto.Free;
  end;
  //
end;

There are several classes (TPersistent) and through the rtti will perform to called the Class/Method according with parameters.
Now, can you understand?

The following detailed example.

class function TCfopController.Consult(pFilter, pPage: String; pComplete: Boolean): TExtjsVO;
var
  objReturn TExtjsVO;
begin
  objReturn := TExtjsVO.Create;
  objReturn.success := true;
  objReturn.total := 1;
  objReturn.rows := 'It is Okay, worked. [TCfoController]';
  result := objReturn;
end;

Other exemple
http://localhost:777/restSF/ObjectJson/?NameClassController=CustomerController.TCustomerController&NameMethod=Consult&Parameters=id=1|1|True

class function TCustomerController.Consult(pFilter, pPage: String; pComplete: Boolean): TExtjsVO;
var
  objReturn TExtjsVO;
begin
  objReturn := TExtjsVO.Create;
  objReturn.success := true;
  objReturn.total := 1;
  objReturn.rows := 'It is Okay, worked. [TCustomerController]';
  result := objReturn;
end;

The code works perfectly with the consumption of a client, but when testo with two clients (threads) on, begin to occur error.

What can I change to no longer the error occurs?

ab

Administrator

From: France

Registered: 2010-06-21

Posts: 14,660

Website

Re: RttiInstanceType.GetMethod is generated exception

By default, method-based services are re-entrant, so it is up to your code to be thread safe.

I guess the way you are using RTTI is not thread-safe.
You should add some critical sections.

See http://synopse.info/files/html/Synopse% … ml#TITL_25

And IMHO not (ab)use of RTTI as such.
Consider defining a list of classes, inheriting from a parent class, to execute methods.
Or even better use interfaces.

fenix

Member

Registered: 2015-08-02

Posts: 3

Re: RttiInstanceType.GetMethod is generated exception

Okay, thanks.

If I use interface, could I use restful?
I tried receive via TSQLRestServerURIContext, but not allow.
I need receive the data via POST/PUT (Ctxt.Call.InBody), but I do not found how do.
Could you give me some tip of how do?
Please, sorry me by my english.

Last edited by fenix (2015-08-03 13:23:08)