Howdy! :wave: I'm working to create user sessions...

# koin

[Seri]

Howdy! 👋

I'm working to create user sessions with Koin scopes! My simple proof-of-concept project has a few issues that I'm seeking help with. Thank you for taking a look!

🧵

[Seri]

I'm looking to scope various resources under the idea of a UserSession. When a session is closed, all of those resources should be cleaned up. When one is opened, they should be recreated. I believe this is a good way to create the scopes for this purpose:

val sessionModule = module {
    single<SessionManager> {
        SessionManager()
    }

    scope<AuthenticatedSession> {
        scopedOf(::AuthenticatedSession)
    }
}

[Seri]

The scopes can be applied to viewmodels and resources like so:

val androidModule = module {
    scope<AuthenticatedSession> {
        viewModel<AuthenticatedViewModel> {
            AuthenticatedViewModel(session = get())
        }
    }

    viewModel<UnauthenticatedViewModel> {
        UnauthenticatedViewModel(sessionManager = get())
    }
}

[Seri]

And finally, the session classes themselves:

SessionManager.kt

class SessionManager {
    var session: AuthenticatedSession? = null

    fun login() {
        session?.logout()
        session = AuthenticatedSession()
    }

    fun logout() {
        session?.logout()
        session = null
    }
}

AuthenticatedSession.kt

class AuthenticatedSession : KoinScopeComponent {
    override val scope: Scope by lazy { createScope(this) }

    val userId = Random.nextInt().toString()
    val logger = getKoin().logger

    init {
        <http://logger.info|logger.info>("AuthenticatedSession created: $userId")
    }

    fun logout() {
        <http://logger.info|logger.info>("AuthenticatedSession close: $userId")
        scope.close()
    }
}

[Seri]

Issue #1
When I call SessionManager.login() from a viewmodel, two sessions with different ID's appear to be created.

2024-09-13 12:33:20.677  9004-9004  [Koin]                  dev.seri.kointests.android           I  AuthenticatedSession close: -1128270103
2024-09-13 12:33:20.679  9004-9004  [Koin]                  dev.seri.kointests.android           I  AuthenticatedSession created: 1187421452

[Seri]

Issue #2
I can only create a ViewModel from an instance of a Scope. This API appears to be missing a Scope.koinViewModel method, similar to the plain koinViewModel. When I inject this way, I appear to be recreating several instances of the ViewModel, rather than reusing the same one.

authenticatedViewModel: AuthenticatedViewModel = session.get<AuthenticatedViewModel>()

[Seri]

Figured it out!

Solution #1
• The duplicate session was being initialized from the scopedOf(::AuthenticatedSession) in my sessionModule. This definition is unnecessary, and ended up created a new scope-of-a-scope field.
Solution #2
• When using koinViewModel() to create a scoped viewModel, simply pass in the scope to resolve from.

[Seri]

I've published my prototype project for managing User Session scopes here! https://github.com/Serisium/KoinSession