Checklist for WebHub applications that should eventually/sometimes run as a Windows service

1. In the DPR, make sure that MultiTypeApp is the first unit listed in the uses clause and that Forms is not listed at all.
2. This step applies if and only if you want to compile with packages, and in particular with the WebHub RT (Run Time) package. In that case, you must edit your DPR and add an extra unit to the uses clause. The unit to add is: MultiTypeAppSvc and you do have PAS source for that in your webhub\lib folder. If you fail to include that unit, you will not be able to install your service.
3. Use a TtpProject component. The easiest way to do this is to use the WebHub new-project wizard to initially create your project.
4. Check Project > Options and make sure that you do NOT have the compiler directive PREVENTSVCMGR because that prevents the Windows service manager from being compiled into your application.
5. In Project > Options > Version, add a custom version string named ServiceName and set it equal to something reasonable for your application.
6. Use Project > Build to rebuild your project such that any changes to compiler directives are taken into consideration.
7. Remember that you have to install your service before it can be started and stopped.

   mywhapp.exe -install
   net start myservicename
   net stop myservicename
   

8. You can also start your application as a normal Windows app, e.g.

   start mywhapp.exe /ID=showcase
   

9. To remove the service, call

   mywhapp.exe -uninstall
   

10. If you want to prevent the service from running due to a fatal error condition detected during startup, call Application.PreventRun.

Customizing the TService object in Delphi

In a Delphi service application which does NOT use MultiTypeApp, you can use the Delphi Object Inspector to set properties of the TService, such as the startup mode and the dependencies. When working with the generic MultiTypeApp unit plus tpAppService.pas, the syntax is a bit more tricky (because we leave you the option of NOT compiling as a service).

Nevertheless, you can still customize all the properties of the TService. To do this, put code into the datamodule which contains TtpProject, in the OnCreate event handler. Here is an example:

// example contributed by Vseslav
// uses SvcMgr
procedure TDMSampleForWHProject.DataModuleCreate(Sender: TObject);
var
  Service: TService;
  i:integer;
begin
  for i := 0 to SvcMgr.Application.ComponentCount - 1 do
    if SvcMgr.Application.Components[i] is TService then
      begin
        Service := TService(SvcMgr.Application.Components[i]);
        // ok to set properties now
//        Service.Dependencies
      end;
end;