I have a situation with a clean domain project (i....

# ktor

[Rohde Fischer]

I have a situation with a clean domain project (i.e. no ktor, exposed or anything) and an api project, depending on the domain, ktor etc. In my domain I have a data class DomainPrincipal that of course does not (and should not) know of ktor Principal. However, when doing JWT mapping in ktor, I want to map to my domain model 🙂 but as far as I know, I cannot really do that because the data class is (as it should be) final.

So, if not much mistaken, I need to work around this, am I correct in this?

If so am I also correct in that there's basically two ways to work around it:
• Having some kind of composition by data class KtorDomainPrincipal(val domainPrincipal: DomainPrincipal): Principal
• Using the by keyword to make a subclass of principal that basically wraps the methods and fields of my DomainPrincipal
is there any pros or cons that I should know of with the two? I think the first is easier to maintain whereas the second will have a cleaner and nicer interface

[Bruce Hamilton]

Generally just using composition is the way to go, then you can add additional session details in the principal. For accessing the domain object you can always add an extension method like ApplicationCall.principal<KtorDomainPrincipal>.domainObject . I'm not entirely sure why the empty placeholder Principal interface exists, it might be useful for us to remove it from Ktor authentication.