Hi folks. I need to retrive information from coroutine context (ktor logged user) in an implementat...

# coroutines

[Ivan]

Hi folks. I need to retrive information from coroutine context (ktor logged user) in an implementation of a function from an abstract java class provided by an external library. I can't implement this function as a suspend function and so i can't access to the coroutine context. Do you have any suggestion?

[Niklas Gürtler]

Does your function need to suspend?

[Ivan]

No, it doesn't.

I need to implement this java abstract class from my kotlin/ktor project:

@FunctionalInterface
public interface CurrentUserProvider {


  Object currentUser();
}

But i can declase currentUser as suspend function, and this function is called from library as an internal callback

[Niklas Gürtler]

@FunctionalInterface
class MyCurrentUserProvider (val coroScope : CoroutineScope) : CurrentUserProvider () {
  
  fun currentUser() : java.lang.Object () {
    coroScope.whatever ()
  }
}

[Ivan]

I already try this solution but coroutine context thet can i pass to MyCurrentUserProvider is different from coroutine context that ktor use on http call and not contain the user info.

I need to find a way to retrive the correct coroutine context directly from currentUser function.

[Niklas Gürtler]

does ktor call currentUser directly? Or does ktor call something in your app, which then calls something in the Java lib, which then calls currentUser?

[Ivan]

the second one

[Niklas Gürtler]

so then can't your app determine the ktor context _bef_ore you call the external library, pass it to your CurrentUserProvider implementation, and then do the call?

[Ivan]

exactly, i think that the only way is to save user information in currentThread in some way when ktor call start and retrieve it from currentUser

[Niklas Gürtler]

why in currentThread? Why not simply in a member variable of your CurrentUserProvider implementation?

[Ivan]

CurrentUserProvider is a singleton, shared for all call

[Niklas Gürtler]

what about passing a lambda that captures the currentContext variable instead of a CurrentUserProvider implementation?

[tateisu]

https://discuss.kotlinlang.org/t/get-current-coroutinecontext-inside-a-regular-function/11568/2

[tateisu]

You need to pass it explicitly to your function as parameter or receiver.

[tateisu]

Technically, it would be even possible to expose coroutineContext as a ThreadLocal.