Example with Polly.CacheAsync with ResultTtl strategy needed

I’ve tried to create a CachePolicy using the ResultTtl strategy. It happens that I have to use IAsyncCacheProvider<TResult> to make it possible, at least against Polly 5.9.0

Unfortunatly I cannot find out how to create such provider. My best guess was to use IDistributedCache provider and a serializer but currently the package doesn’t look present on nuget https://www.nuget.org/packages/polly.caching.serialization.json

Could someone guide me further on this?

[AndreaCuneo]

I tried the following code with polly 5.9.0 but I get the following error compiling.

#if NETSTANDARD2_0
        Polly.Caching.MemoryCache.MemoryCacheProvider _memoryCacheProvider
           = new Polly.Caching.MemoryCache.MemoryCacheProvider(new Microsoft.Extensions.Caching.Memory.MemoryCache(new Microsoft.Extensions.Caching.Memory.MemoryCacheOptions()));
#else 
        Polly.Caching.MemoryCache.MemoryCacheProvider _memoryCacheProvider
           = new Polly.Caching.MemoryCache.MemoryCacheProvider(System.Runtime.Caching.MemoryCache.Default);
#endif

var cachePolicy = Policy.CacheAsync<(string AccessToken, DateTimeOffset ExpiresOn)>(_memoryCacheProvider, new ResultTtl<(string AccessToken, DateTimeOffset ExpiresOn)>(r => new Ttl(r.ExpiresOn - DateTimeOffset.Now, false)));

Argument 2: cannot convert from ‘Polly.Caching.ResultTtl<(string AccessToken, System.DateTimeOffset ExpiresOn)>’ to ‘System.TimeSpan’

And makes sense as there is no overload that accept ITtlStrategy<TResult> and a plain IAsyncCacheProvider. It requires IAsyncCacheProvider<TResult> but I do not find how to make one. If I update to Polly v6, there is a version clashing where Polly.Caching.MemoryCache.MemoryCacheProvider doesn’t implement Polly.Caching.IAsyncCacheProvider from v6 and requires v5.9

Am I doing something wrong?

[reisenberger]

I confirm that AsyncFor<> solves. I couldn’t find that, or I missed it completly, from every doc page I looked at

Documentation now added: https://github.com/App-vNext/Polly.Caching.MemoryCache#note . Thanks for highlighting this issue!