per feedback on #53255, try non-generic primary API

src/Caching/Caching/src/DistributedCacheServiceExtensions.cs

@@ -22,7 +22,7 @@ public static IServiceCollection AddTypedDistributedCache(this IServiceCollectio
         services.AddDistributedMemoryCache(); // we need a backend; use in-proc by default
         services.TryAddSingleton(typeof(ICacheSerializer<string>), typeof(StringSerializer));
         services.TryAddSingleton(typeof(ICacheSerializer<>), typeof(DefaultJsonSerializer<>));
-        services.AddSingleton(typeof(IDistributedCache<>), typeof(DistributedCache<>));
+        services.AddSingleton(typeof(IAdvancedDistributedCache), typeof(DistributedCache));
         return services;
     }
 }

src/Caching/Caching/src/DistributedCacheT.cs

@@ -1,44 +1,48 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System;
 using System.Buffers;
 using Microsoft.AspNetCore.OutputCaching;
 using Microsoft.Extensions.Options;
 
 namespace Microsoft.Extensions.Caching.Distributed;
-internal sealed class DistributedCache<T> : IDistributedCache<T>
+internal sealed class DistributedCache : IAdvancedDistributedCache
 {
-    private readonly ICacheSerializer<T> _serializer;
+    private readonly IServiceProvider _services;
     private readonly IDistributedCache _backend;
     private readonly IBufferDistributedCache? _bufferBackend;
 
-    public DistributedCache(IOptions<TypedDistributedCacheOptions> options, ICacheSerializer<T> serializer, IDistributedCache backend)
+    public DistributedCache(IOptions<TypedDistributedCacheOptions> options, IServiceProvider services, IDistributedCache backend)
     {
-        _serializer = serializer;
+        _services = services;
         _backend = backend;
         _bufferBackend = backend as IBufferDistributedCache; // do the type test once only
         _ = options;
     }
 
-    // for the simple usage scenario (no TState), pack the original callback as the "state", and use a wrapper function that just unrolls and invokes from the state
-    static readonly Func<Func<CancellationToken, ValueTask<T>>, CancellationToken, ValueTask<T>> _wrapped = static (callback, ct) => callback(ct);
-    public ValueTask<T> GetAsync(string key, Func<CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options = null, CancellationToken cancellationToken = default)
-        => GetAsync(key, callback, _wrapped, options, cancellationToken);
+    static class WrappedCallbackCache<T>
+    {
+        // for the simple usage scenario (no TState), pack the original callback as the "state", and use a wrapper function that just unrolls and invokes from the state
+        public static readonly Func<Func<CancellationToken, ValueTask<T>>, CancellationToken, ValueTask<T>> Instance = static (callback, ct) => callback(ct);
+
+    }
+    public ValueTask<T> GetAsync<T>(string key, Func<CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options = null, CancellationToken cancellationToken = default)
+        => GetAsync(key, callback, WrappedCallbackCache<T>.Instance, options, cancellationToken);
 
-    public ValueTask<T> GetAsync<TState>(string key, TState state, Func<TState, CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options = null, CancellationToken cancellationToken = default)
+    public ValueTask<T> GetAsync<TState, T>(string key, TState state, Func<TState, CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options = null, CancellationToken cancellationToken = default)
     {
         ArgumentException.ThrowIfNullOrWhiteSpace(key);
         ArgumentNullException.ThrowIfNull(callback);
 
         return _bufferBackend is not null
             ? GetBufferedBackendAsync(key, state, callback, options, cancellationToken)
             : GetLegacyBackendAsync(key, state, callback, options, cancellationToken);
-
     }
 
-    ValueTask IDistributedCache<T>.RefreshAsync(string key, CancellationToken cancellationToken) => new(_backend.RefreshAsync(key, cancellationToken));
+    ValueTask IAdvancedDistributedCache.RefreshAsync(string key, CancellationToken cancellationToken) => new(_backend.RefreshAsync(key, cancellationToken));
 
-    private ValueTask<T> GetBufferedBackendAsync<TState>(string key, TState state, Func<TState, CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options, CancellationToken cancellationToken)
+    private ValueTask<T> GetBufferedBackendAsync<TState, T>(string key, TState state, Func<TState, CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options, CancellationToken cancellationToken)
     {
         var buffer = new RecyclableArrayBufferWriter<byte>();
         var pendingGet = _bufferBackend!.TryGetAsync(key, buffer, cancellationToken);
@@ -51,22 +55,22 @@ private ValueTask<T> GetBufferedBackendAsync<TState>(string key, TState state, F
         // fast path; backend available immediately
         if (pendingGet.GetAwaiter().GetResult())
         {
-            var result = _serializer.Deserialize(new(buffer.GetCommittedMemory()));
+            var result = GetSerializer<T>().Deserialize(new(buffer.GetCommittedMemory()));
             buffer.Dispose();
             return new(result);
         }
 
         // fall back to main code-path, but without the pending bytes (we've already checked those)
         return AwaitedBackend(this, key, state, callback, options, cancellationToken, buffer, default);
 
-        static async ValueTask<T> AwaitedBackend(DistributedCache<T> @this, string key, TState state, Func<TState, CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options,
+        static async ValueTask<T> AwaitedBackend(DistributedCache @this, string key, TState state, Func<TState, CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options,
              CancellationToken cancellationToken, RecyclableArrayBufferWriter<byte> buffer, ValueTask<bool> pendingGet)
         {
             using (buffer)
             {
                 if (await pendingGet)
                 {
-                    return @this._serializer.Deserialize(new(buffer.GetCommittedMemory()));
+                    return @this.GetSerializer<T>().Deserialize(new(buffer.GetCommittedMemory()));
                 }
 
                 var value = await callback(state, cancellationToken);
@@ -77,7 +81,7 @@ static async ValueTask<T> AwaitedBackend(DistributedCache<T> @this, string key,
                 else
                 {
                     buffer.Reset();
-                    @this._serializer.Serialize(value, buffer);
+                    @this.GetSerializer<T>().Serialize(value, buffer);
                     await @this._bufferBackend!.SetAsync(key, new(buffer.GetCommittedMemory()), options ?? _defaultOptions, cancellationToken);
                 }
 
@@ -86,7 +90,20 @@ static async ValueTask<T> AwaitedBackend(DistributedCache<T> @this, string key,
         }
     }
 
-    private ValueTask<T> GetLegacyBackendAsync<TState>(string key, TState state, Func<TState,  CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options, CancellationToken cancellationToken)
+    private ICacheSerializer<T> GetSerializer<T>()
+    {
+        var obj = (ICacheSerializer<T>?)_services.GetService(typeof(ICacheSerializer<T>));
+        if (obj is null)
+        {
+            ThrowNoSerializer(typeof(T));
+        }
+        return obj!;
+
+    }
+
+    static void ThrowNoSerializer(Type type) => throw new InvalidOperationException("No serializer registered for " + type.FullName);
+
+    private ValueTask<T> GetLegacyBackendAsync<TState, T>(string key, TState state, Func<TState,  CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options, CancellationToken cancellationToken)
     {
         var pendingBytes = _backend.GetAsync(key, cancellationToken);
         if (!pendingBytes.IsCompletedSuccessfully)
@@ -98,21 +115,21 @@ private ValueTask<T> GetLegacyBackendAsync<TState>(string key, TState state, Fun
         var bytes = pendingBytes.Result;
         if (bytes is not null)
         {
-            return new(_serializer.Deserialize(new ReadOnlySequence<byte>(bytes))!);
+            return new(GetSerializer<T>().Deserialize(new ReadOnlySequence<byte>(bytes))!);
         }
 
         // fall back to main code-path, but without the pending bytes (we've already checked those)
         return AwaitedBackend(this, key, state, callback, options, cancellationToken, null);
 
-        static async ValueTask<T> AwaitedBackend(DistributedCache<T> @this, string key, TState state, Func<TState, CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options,
+        static async ValueTask<T> AwaitedBackend(DistributedCache @this, string key, TState state, Func<TState, CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options,
              CancellationToken cancellationToken, Task<byte[]?>? pendingBytes)
         {
             if (pendingBytes is not null)
             {
                 var bytes = await pendingBytes;
                 if (bytes is not null)
                 {
-                    return @this._serializer.Deserialize(new ReadOnlySequence<byte>(bytes));
+                    return @this.GetSerializer<T>().Deserialize(new ReadOnlySequence<byte>(bytes));
                 }
             }
 
@@ -124,7 +141,7 @@ static async ValueTask<T> AwaitedBackend(DistributedCache<T> @this, string key,
             else
             {
                 using var writer = new RecyclableArrayBufferWriter<byte>();
-                @this._serializer.Serialize(value, writer);
+                @this.GetSerializer<T>().Serialize(value, writer);
                 await @this._backend.SetAsync(key, writer.ToArray(), options ?? _defaultOptions, cancellationToken);
             }
 

src/Caching/Caching/src/IDistributedCacheT.cs

@@ -5,13 +5,13 @@
 
 namespace Microsoft.Extensions.Caching.Distributed;
 
-public interface IDistributedCache<T>
+public interface IAdvancedDistributedCache
 {
     [SuppressMessage("ApiDesign", "RS0026:Do not add multiple public overloads with optional parameters", Justification = "Does not cause ambiguity due to callback signature delta")]
-    ValueTask<T> GetAsync(string key, Func<CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options = null, CancellationToken cancellationToken = default);
+    ValueTask<T> GetAsync<T>(string key, Func<CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options = null, CancellationToken cancellationToken = default);
 
     [SuppressMessage("ApiDesign", "RS0026:Do not add multiple public overloads with optional parameters", Justification = "Does not cause ambiguity due to callback signature delta")]
-    ValueTask<T> GetAsync<TState>(string key, TState state, Func<TState, CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options = null, CancellationToken cancellationToken = default);
+    ValueTask<T> GetAsync<TState, T>(string key, TState state, Func<TState, CancellationToken, ValueTask<T>> callback, DistributedCacheEntryOptions? options = null, CancellationToken cancellationToken = default);
 
     ValueTask RemoveAsync(string key, CancellationToken cancellationToken = default);
 

src/Caching/Caching/src/PublicAPI.Unshipped.txt

@@ -1,16 +1,16 @@
 #nullable enable
 Microsoft.Extensions.Caching.Distributed.DistributedCacheServiceExtensions
+Microsoft.Extensions.Caching.Distributed.IAdvancedDistributedCache
+Microsoft.Extensions.Caching.Distributed.IAdvancedDistributedCache.GetAsync<T>(string! key, System.Func<System.Threading.CancellationToken, System.Threading.Tasks.ValueTask<T>>! callback, Microsoft.Extensions.Caching.Distributed.DistributedCacheEntryOptions? options = null, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<T>
+Microsoft.Extensions.Caching.Distributed.IAdvancedDistributedCache.GetAsync<TState, T>(string! key, TState state, System.Func<TState, System.Threading.CancellationToken, System.Threading.Tasks.ValueTask<T>>! callback, Microsoft.Extensions.Caching.Distributed.DistributedCacheEntryOptions? options = null, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<T>
+Microsoft.Extensions.Caching.Distributed.IAdvancedDistributedCache.RefreshAsync(string! key, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
+Microsoft.Extensions.Caching.Distributed.IAdvancedDistributedCache.RemoveAsync(string! key, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
 Microsoft.Extensions.Caching.Distributed.IBufferDistributedCache
 Microsoft.Extensions.Caching.Distributed.IBufferDistributedCache.SetAsync(string! key, System.Buffers.ReadOnlySequence<byte> value, Microsoft.Extensions.Caching.Distributed.DistributedCacheEntryOptions! options, System.Threading.CancellationToken cancellationToken) -> System.Threading.Tasks.ValueTask
 Microsoft.Extensions.Caching.Distributed.IBufferDistributedCache.TryGetAsync(string! key, System.Buffers.IBufferWriter<byte>! destination, System.Threading.CancellationToken cancellationToken) -> System.Threading.Tasks.ValueTask<bool>
 Microsoft.Extensions.Caching.Distributed.ICacheSerializer<T>
 Microsoft.Extensions.Caching.Distributed.ICacheSerializer<T>.Deserialize(System.Buffers.ReadOnlySequence<byte> source) -> T
 Microsoft.Extensions.Caching.Distributed.ICacheSerializer<T>.Serialize(T value, System.Buffers.IBufferWriter<byte>! target) -> void
-Microsoft.Extensions.Caching.Distributed.IDistributedCache<T>
-Microsoft.Extensions.Caching.Distributed.IDistributedCache<T>.GetAsync(string! key, System.Func<System.Threading.CancellationToken, System.Threading.Tasks.ValueTask<T>>! callback, Microsoft.Extensions.Caching.Distributed.DistributedCacheEntryOptions? options = null, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<T>
-Microsoft.Extensions.Caching.Distributed.IDistributedCache<T>.GetAsync<TState>(string! key, TState state, System.Func<TState, System.Threading.CancellationToken, System.Threading.Tasks.ValueTask<T>>! callback, Microsoft.Extensions.Caching.Distributed.DistributedCacheEntryOptions? options = null, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<T>
-Microsoft.Extensions.Caching.Distributed.IDistributedCache<T>.RefreshAsync(string! key, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
-Microsoft.Extensions.Caching.Distributed.IDistributedCache<T>.RemoveAsync(string! key, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
 Microsoft.Extensions.Caching.Distributed.IDistributedCacheInvalidation
 Microsoft.Extensions.Caching.Distributed.IDistributedCacheInvalidation.CacheKeyInvalidated -> System.Func<string!, System.Threading.Tasks.ValueTask>!
 Microsoft.Extensions.Caching.Distributed.TypedDistributedCacheOptions

src/Caching/Caching/test/CacheConfigTests.cs

@@ -104,7 +104,7 @@ public async Task StatefulUsage(bool useCustomBackend)
     }
 }
 
-public class SomeService(IDistributedCache<Foo> cache)
+public class SomeService(IAdvancedDistributedCache cache)
 {
     private int _backendCalls;
     public int BackendCalls => _backendCalls;