Using GetOrFetchObject never seems to invalidate objects

[TheAngryByrd]

Using thee GetOrFetchObject for operations that write to disk, it never seem to invalidate using the absolute expiration.

[anaisbetts]

How are you testing that it's not invalidating?

[TheAngryByrd]

Maybe I'm just using it wrong?

I have a project here: https://github.com/TheAngryByrd/GetOrFetchProblem/

If you notice in the Mainpage.xaml.cs, the OnNavigatedTo demostrates what i'm trying to do.

I call :

  var value = await BlobCache.LocalMachine.GetOrFetchObject("key", () => GetThing(), DateTimeOffset.Now.AddSeconds(10));

and it will write out the console when GetThing() gets called and when it returns a value.

Now if you stop the app, wait 10 seconds and open it back up, it never seems to call GetThing() again.

[anaisbetts]

I think I know what's happening. You're killing the app via the Stop button, and you're using the deprecated backend (i.e. not SQLite3) - when you do this (and you don't Dispose BlobCache on shutdown), Akavache doesn't flush the metadata so it loses the expiration.

[anaisbetts]

Here's the 411:

https://github.com/github/Akavache/blob/master/Akavache/PersistentBlobCache.cs#L104

We need at least 30sec of idle time before we'll attempt to flush the cache. If you make a bunch of writes then immediately kill it and you don't shutdown the blob cache properly, you'll see this. The way to shut it down is:

BlobCache.LocalMachine.Dispose();
await BlobCache.Shutdown;

[TheAngryByrd]

Ok awesome. I'll make sure to do that.

Or maybe I'll move to using sqllite.

Thanks!