Is there a simple way of accessing the cache directory path from common kotlin code, without passing...

# multiplatform

[Sam]

Is there a simple way of accessing the cache directory path from common kotlin code, without passing it through from iOS/Android? I want to write some common caching logic that reads and writes from files in the cache directory

[Andrei Salavei]

Does expect/actual implementation help you here?

[Sam]

Yeah so I can write file writing/reading logic using expect/actual implementations easily enough, it's getting hold of the directory path to write to that I'm struggling with

[Andrei Salavei]

But you can use the same approach to implement the expect/actual method that returns cache directory path for each platform. Do you?

[Sam]

That's my current question? Is there a way of accessing those directory paths from within the common module (even if that is in the androidMain & iOSMain source sets?

[Sam]

I think I have a solution on iOS

val paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, true);
val cacheDirectory = paths.first()

[Vidmantas Kerbelis]

Well, if you want to just get the path or something, then expect/actual is your friend here.
If you want to get a File and do something with it in common code. So CRUD operations, or w/e.. Then you probably need something like Okio and use FileSystem to open the appropriate files from the cache.

[Sam]

As I said I know I can use expect/actual to execute platform specific code, the issue actually getting hold of the correct path. The snippet above correctly gets the cache directory on iOS, does anyone know of an android equivilent ?

[Vidmantas Kerbelis]

In most cases for Android it’s just:

context.cacheDir (File), so for the path, it would be cacheDir.absolutePath (or relativePath)

[Sam]

I'm in in common code here though so don't have easy access to a context (I'm building a library and ideally don't want to make the user pass in the context manually on Android).

Context would defo be the way to go in native android

[Vidmantas Kerbelis]

To access the Android resource system you need to have Context, so you must do it on the Android platform’s side sadly

[Sam]

No probs, thanks!

[Jeff Lockhart]

korio has a nice way of handling the Android Context in common code. It embeds the Android Context within the coroutine context, which then can be used by Android actual suspend functions on file systems objects like cacheVfs. You just need to call withAndroidContext(context) from the Android code the calls the common code (example).