SMAppService - How does this work?

Nice! I was one of the last Pascal holdouts on traditional Mac OS. I only moved to C when I joined Apple. I was never happy with that, and that’s one of the reasons why I’m a huge fan of Swift.

Sure. I’m gonna focus on Swift, because that’ll be the most useful to a general audience, but I’ll come back to your specific tools later on.

To add your app as a login item using SMAppService:

1. Import the framework.

2. Create a service for your own app.

3. Call register() on it.

Here’s what that looks like:

import ServiceManagement
 
func registerAppServiceAsLoginItem() throws {
    let service = SMAppService.mainApp
    try service.register()
}

You do this straight from your app; there’s no indirection required.

Indeed, there was no indirection required by SMLoginItemSetEnabled either. I suspect that this indirection was introduced by your tooling.

Speaking of which, do your tools have a mechanism for calling native C code? This is often called a foreign function interface (FFI).

If so, my advice would be to write an Objective-C version of the above code [1], wrap that in a C function, and then call that from your app’s actual code.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

[1] Here’s the C header:

#ifndef SMAppServiceRegister_h
#define SMAppServiceRegister_h
 
extern int registerAppServiceAsLoginItem(void);
 
#endif /* SMAppServiceRegister_h */

And here’s the Objective-C implementation:

#include "SMAppServiceRegister.h"
 
@import ServiceManagement;
 
extern int registerAppServiceAsLoginItem(void) {
    SMAppService * service = [SMAppService mainAppService];
    BOOL success = [service registerAndReturnError:NULL];
    return success;
}

Thank you for the very clear and helpful assist! 😊

I may be able to convert the ObjC calls to Objective Pascal so I could call these functions directly (with some luck and patience). I assume that signing the application is a requirement when testing?

If I cannot get this to work, then I'll use your suggestion - let me tinker for a bit and see what I can get to work 😊 I'll come back here if I have a working solution - as it could be useful for others.

Note: The approach with helper tools seemed rather unnecessarily complicated, so it is nice to hear that I can do this straight in the main application. Things like this make it harder and harder to enjoy developing the little tools I make for fun. 😉

Thanks again for helping! It is very much appreciated.

Got it to work thanks to your tips and suggestions.

1. Created a unit to interact with SMAppService:

unit ServiceManagementAppService;
 
{$mode objfpc}{$H+}
{$modeswitch objectivec1}
{$linkframework ServiceManagement}
 
interface
 
uses Classes, SysUtils, CocoaAll;
 
const
  SMAppServiceStatusNotRegistered	=0;
  SMAppServiceStatusEnabled		=1; 
  SMAppServiceStatusRequiresApproval	=2; 
  SMAppServiceStatusNotFound		=3;
 
  SmAppServiceStatusResult :
    Array [0..3] of string = 
                            ('Not registered',
                              'Enabled',
                              'Requires Approval',
                              'Not found' );  
type
  SMAppServiceStatus = NSInteger;
  
type
  SMAppService = objcclass external (NSObject)
  public
    function  registerAndReturnError(error: NSErrorPtr): objcbool;  message 'registerAndReturnError:';
    function  unregisterAndReturnError(error: NSErrorPtr): objcbool;  message 'unregisterAndReturnError:';
    function  status:SMAppServiceStatus; message 'status';
  end;
 
implementation
 
end.

1. And in my main application for some random testing:

procedure TForm1.Button1Click(Sender: TObject);
var
  appService: SMAppService;
  StatusReturn : SMAppServiceStatus;
  Registered:boolean;
begin
  try
    // Create a service
    appService := SMAppService.new;
 
    // Get current status
    StatusReturn := appService.status;
    ShowMessage('Status: '+IntToStr(Integer(StatusReturn))+LineEnding+ SmAppServiceStatusResult[StatusReturn]);
 
    // Resgister service
    Registered := appService.registerAndReturnError(nil);
    ShowMessage('Registering result: '+BoolToStr(Registered,'Success','Failed'));
 
    // Get current status
    StatusReturn := appService.status;
    ShowMessage('Status: '+IntToStr(Integer(StatusReturn))+LineEnding+ SmAppServiceStatusResult[StatusReturn]);
 
    // Resgister service
    Registered := appService.unregisterAndReturnError(nil);
    ShowMessage('Unregistering result: '+BoolToStr(Registered,'Success','Failed'));
 
    // Get current status
    StatusReturn := appService.status;
    ShowMessage('Status: '+IntToStr(Integer(StatusReturn))+LineEnding+ SmAppServiceStatusResult[StatusReturn]);
  except
    Showmessage('fail');
  end;
end; 

Note:

• while testing it seemed I needed to sign the app bundle of my application
• I haven't tested this yet in the App Store (I know that I need to make the user make this choice)

I hope this is useful to someone and feel free to correct me if I goofed up somehow. 😊

Thanks again!