Make IChatClient/IEmbeddingGenerator.GetService non-generic (#5608)

src/Libraries/Microsoft.Extensions.AI.Abstractions/ChatCompletion/ChatClientExtensions.cs

@@ -11,6 +11,22 @@ namespace Microsoft.Extensions.AI;
 /// <summary>Provides a collection of static methods for extending <see cref="IChatClient"/> instances.</summary>
 public static class ChatClientExtensions
 {
+    /// <summary>Asks the <see cref="IChatClient"/> for an object of type <typeparamref name="TService"/>.</summary>
+    /// <typeparam name="TService">The type of the object to be retrieved.</typeparam>
+    /// <param name="client">The client.</param>
+    /// <param name="serviceKey">An optional key that may be used to help identify the target service.</param>
+    /// <returns>The found object, otherwise <see langword="null"/>.</returns>
+    /// <remarks>
+    /// The purpose of this method is to allow for the retrieval of strongly-typed services that may be provided by the <see cref="IChatClient"/>,
+    /// including itself or any services it might be wrapping.
+    /// </remarks>
+    public static TService? GetService<TService>(this IChatClient client, object? serviceKey = null)
+    {
+        _ = Throw.IfNull(client);
+
+        return (TService?)client.GetService(typeof(TService), serviceKey);
+    }
+
     /// <summary>Sends a user chat text message to the model and returns the response messages.</summary>
     /// <param name="client">The chat client.</param>
     /// <param name="chatMessage">The text content for the chat message to send.</param>

src/Libraries/Microsoft.Extensions.AI.Abstractions/ChatCompletion/DelegatingChatClient.cs

@@ -63,12 +63,13 @@ public class DelegatingChatClient : IChatClient
     }
 
     /// <inheritdoc />
-    public virtual TService? GetService<TService>(object? key = null)
-        where TService : class
+    public virtual object? GetService(Type serviceType, object? serviceKey = null)
     {
-#pragma warning disable S3060 // "is" should not be used with "this"
-        // If the key is non-null, we don't know what it means so pass through to the inner service
-        return key is null && this is TService service ? service : InnerClient.GetService<TService>(key);
-#pragma warning restore S3060
+        _ = Throw.IfNull(serviceType);
+
+        // If the key is non-null, we don't know what it means so pass through to the inner service.
+        return
+            serviceKey is null && serviceType.IsInstanceOfType(this) ? this :
+            InnerClient.GetService(serviceType, serviceKey);
     }
 }

src/Libraries/Microsoft.Extensions.AI.Abstractions/ChatCompletion/IChatClient.cs

@@ -56,14 +56,13 @@ public interface IChatClient : IDisposable
     /// <summary>Gets metadata that describes the <see cref="IChatClient"/>.</summary>
     ChatClientMetadata Metadata { get; }
 
-    /// <summary>Asks the <see cref="IChatClient"/> for an object of type <typeparamref name="TService"/>.</summary>
-    /// <typeparam name="TService">The type of the object to be retrieved.</typeparam>
-    /// <param name="key">An optional key that may be used to help identify the target service.</param>
+    /// <summary>Asks the <see cref="IChatClient"/> for an object of the specified type <paramref name="serviceType"/>.</summary>
+    /// <param name="serviceType">The type of object being requested.</param>
+    /// <param name="serviceKey">An optional key that may be used to help identify the target service.</param>
     /// <returns>The found object, otherwise <see langword="null"/>.</returns>
     /// <remarks>
     /// The purpose of this method is to allow for the retrieval of strongly-typed services that may be provided by the <see cref="IChatClient"/>,
     /// including itself or any services it might be wrapping.
     /// </remarks>
-    TService? GetService<TService>(object? key = null)
-        where TService : class;
+    object? GetService(Type serviceType, object? serviceKey = null);
 }

src/Libraries/Microsoft.Extensions.AI.Abstractions/Embeddings/DelegatingEmbeddingGenerator.cs

@@ -59,12 +59,13 @@ public class DelegatingEmbeddingGenerator<TInput, TEmbedding> : IEmbeddingGenera
         InnerGenerator.GenerateAsync(values, options, cancellationToken);
 
     /// <inheritdoc />
-    public virtual TService? GetService<TService>(object? key = null)
-        where TService : class
+    public virtual object? GetService(Type serviceType, object? serviceKey = null)
     {
-#pragma warning disable S3060 // "is" should not be used with "this"
-        // If the key is non-null, we don't know what it means so pass through to the inner service
-        return key is null && this is TService service ? service : InnerGenerator.GetService<TService>(key);
-#pragma warning restore S3060
+        _ = Throw.IfNull(serviceType);
+
+        // If the key is non-null, we don't know what it means so pass through to the inner service.
+        return
+            serviceKey is null && serviceType.IsInstanceOfType(this) ? this :
+            InnerGenerator.GetService(serviceType, serviceKey);
     }
 }

src/Libraries/Microsoft.Extensions.AI.Abstractions/Embeddings/EmbeddingGeneratorExtensions.cs

@@ -15,6 +15,43 @@ namespace Microsoft.Extensions.AI;
 /// <summary>Provides a collection of static methods for extending <see cref="IEmbeddingGenerator{TInput,TEmbedding}"/> instances.</summary>
 public static class EmbeddingGeneratorExtensions
 {
+    /// <summary>Asks the <see cref="IEmbeddingGenerator{TInput,TEmbedding}"/> for an object of type <typeparamref name="TService"/>.</summary>
+    /// <typeparam name="TInput">The type from which embeddings will be generated.</typeparam>
+    /// <typeparam name="TEmbedding">The numeric type of the embedding data.</typeparam>
+    /// <typeparam name="TService">The type of the object to be retrieved.</typeparam>
+    /// <param name="generator">The generator.</param>
+    /// <param name="serviceKey">An optional key that may be used to help identify the target service.</param>
+    /// <returns>The found object, otherwise <see langword="null"/>.</returns>
+    /// <remarks>
+    /// The purpose of this method is to allow for the retrieval of strongly-typed services that may be provided by the
+    /// <see cref="IEmbeddingGenerator{TInput,TEmbedding}"/>, including itself or any services it might be wrapping.
+    /// </remarks>
+    public static TService? GetService<TInput, TEmbedding, TService>(this IEmbeddingGenerator<TInput, TEmbedding> generator, object? serviceKey = null)
+        where TEmbedding : Embedding
+    {
+        _ = Throw.IfNull(generator);
+
+        return (TService?)generator.GetService(typeof(TService), serviceKey);
+    }
+
+    // The following overload exists purely to work around the lack of partial generic type inference.
+    // Given an IEmbeddingGenerator<TInput, TEmbedding> generator, to call GetService with TService, you still need
+    // to re-specify both TInput and TEmbedding, e.g. generator.GetService<string, Embedding<float>, TService>.
+    // The case of string/Embedding<float> is by far the most common case today, so this overload exists as an
+    // accelerator to allow it to be written simply as generator.GetService<TService>.
+
+    /// <summary>Asks the <see cref="IEmbeddingGenerator{TInput, TEmbedding}"/> for an object of type <typeparamref name="TService"/>.</summary>
+    /// <typeparam name="TService">The type of the object to be retrieved.</typeparam>
+    /// <param name="generator">The generator.</param>
+    /// <param name="serviceKey">An optional key that may be used to help identify the target service.</param>
+    /// <returns>The found object, otherwise <see langword="null"/>.</returns>
+    /// <remarks>
+    /// The purpose of this method is to allow for the retrieval of strongly-typed services that may be provided by the
+    /// <see cref="IEmbeddingGenerator{TInput,TEmbedding}"/>, including itself or any services it might be wrapping.
+    /// </remarks>
+    public static TService? GetService<TService>(this IEmbeddingGenerator<string, Embedding<float>> generator, object? serviceKey = null) =>
+        GetService<string, Embedding<float>, TService>(generator, serviceKey);
+
     /// <summary>Generates an embedding vector from the specified <paramref name="value"/>.</summary>
     /// <typeparam name="TInput">The type from which embeddings will be generated.</typeparam>
     /// <typeparam name="TEmbedding">The numeric type of the embedding data.</typeparam>

src/Libraries/Microsoft.Extensions.AI.Abstractions/Embeddings/IEmbeddingGenerator.cs

@@ -40,14 +40,13 @@ public interface IEmbeddingGenerator<TInput, TEmbedding> : IDisposable
     /// <summary>Gets metadata that describes the <see cref="IEmbeddingGenerator{TInput, TEmbedding}"/>.</summary>
     EmbeddingGeneratorMetadata Metadata { get; }
 
-    /// <summary>Asks the <see cref="IEmbeddingGenerator{TInput, TEmbedding}"/> for an object of type <typeparamref name="TService"/>.</summary>
-    /// <typeparam name="TService">The type of the object to be retrieved.</typeparam>
-    /// <param name="key">An optional key that may be used to help identify the target service.</param>
+    /// <summary>Asks the <see cref="IEmbeddingGenerator{TInput, TEmbedding}"/> for an object of the specified type <paramref name="serviceType"/>.</summary>
+    /// <param name="serviceType">The type of object being requested.</param>
+    /// <param name="serviceKey">An optional key that may be used to help identify the target service.</param>
     /// <returns>The found object, otherwise <see langword="null"/>.</returns>
     /// <remarks>
-    /// The purpose of this method is to allow for the retrieval of strongly-typed services that may be provided by the <see cref="IEmbeddingGenerator{TInput, TEmbedding}"/>,
-    /// including itself or any services it might be wrapping.
+    /// The purpose of this method is to allow for the retrieval of strongly-typed services that may be provided by the
+    /// <see cref="IEmbeddingGenerator{TInput, TEmbedding}"/>, including itself or any services it might be wrapping.
     /// </remarks>
-    TService? GetService<TService>(object? key = null)
-        where TService : class;
+    object? GetService(Type serviceType, object? serviceKey = null);
 }

src/Libraries/Microsoft.Extensions.AI.AzureAIInference/AzureAIInferenceChatClient.cs

@@ -57,10 +57,16 @@ public sealed class AzureAIInferenceChatClient : IChatClient
     public ChatClientMetadata Metadata { get; }
 
     /// <inheritdoc />
-    public TService? GetService<TService>(object? key = null)
-        where TService : class =>
-        typeof(TService) == typeof(ChatCompletionsClient) ? (TService?)(object?)_chatCompletionsClient :
-        this as TService;
+    public object? GetService(Type serviceType, object? serviceKey = null)
+    {
+        _ = Throw.IfNull(serviceType);
+
+        return
+            serviceKey is not null ? null :
+            serviceType == typeof(ChatCompletionsClient) ? _chatCompletionsClient :
+            serviceType.IsInstanceOfType(this) ? this :
+            null;
+    }
 
     /// <inheritdoc />
     public async Task<ChatCompletion> CompleteAsync(

src/Libraries/Microsoft.Extensions.AI.AzureAIInference/AzureAIInferenceEmbeddingGenerator.cs

@@ -70,10 +70,16 @@ public sealed class AzureAIInferenceEmbeddingGenerator :
     public EmbeddingGeneratorMetadata Metadata { get; }
 
     /// <inheritdoc />
-    public TService? GetService<TService>(object? key = null)
-        where TService : class =>
-        typeof(TService) == typeof(EmbeddingsClient) ? (TService)(object)_embeddingsClient :
-        this as TService;
+    public object? GetService(Type serviceType, object? serviceKey = null)
+    {
+        _ = Throw.IfNull(serviceType);
+
+        return
+            serviceKey is not null ? null :
+            serviceType == typeof(EmbeddingsClient) ? _embeddingsClient :
+            serviceType.IsInstanceOfType(this) ? this :
+            null;
+    }
 
     /// <inheritdoc />
     public async Task<GeneratedEmbeddings<Embedding<float>>> GenerateAsync(

src/Libraries/Microsoft.Extensions.AI.Ollama/OllamaChatClient.cs

@@ -166,9 +166,14 @@ public sealed class OllamaChatClient : IChatClient
     }
 
     /// <inheritdoc />
-    public TService? GetService<TService>(object? key = null)
-        where TService : class
-        => key is null ? this as TService : null;
+    public object? GetService(Type serviceType, object? serviceKey = null)
+    {
+        _ = Throw.IfNull(serviceType);
+
+        return
+            serviceKey is null && serviceType.IsInstanceOfType(this) ? this :
+            null;
+    }
 
     /// <inheritdoc />
     public void Dispose()

src/Libraries/Microsoft.Extensions.AI.Ollama/OllamaEmbeddingGenerator.cs

@@ -57,9 +57,14 @@ public sealed class OllamaEmbeddingGenerator : IEmbeddingGenerator<string, Embed
     public EmbeddingGeneratorMetadata Metadata { get; }
 
     /// <inheritdoc />
-    public TService? GetService<TService>(object? key = null)
-        where TService : class
-        => key is null ? this as TService : null;
+    public object? GetService(Type serviceType, object? serviceKey = null)
+    {
+        _ = Throw.IfNull(serviceType);
+
+        return
+            serviceKey is null && serviceType.IsInstanceOfType(this) ? this :
+            null;
+    }
 
     /// <inheritdoc />
     public void Dispose()

src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIChatClient.cs

@@ -16,6 +16,7 @@ using Microsoft.Shared.Diagnostics;
 using OpenAI;
 using OpenAI.Chat;
 
+#pragma warning disable S1067 // Expressions should not be too complex
 #pragma warning disable S1135 // Track uses of "TODO" tags
 #pragma warning disable S3011 // Reflection should not be used to increase accessibility of classes, methods, or fields
 #pragma warning disable SA1204 // Static elements should appear before instance elements
@@ -85,11 +86,17 @@ public sealed partial class OpenAIChatClient : IChatClient
     public ChatClientMetadata Metadata { get; }
 
     /// <inheritdoc />
-    public TService? GetService<TService>(object? key = null)
-        where TService : class =>
-        typeof(TService) == typeof(OpenAIClient) ? (TService?)(object?)_openAIClient :
-        typeof(TService) == typeof(ChatClient) ? (TService)(object)_chatClient :
-        this as TService;
+    public object? GetService(Type serviceType, object? serviceKey = null)
+    {
+        _ = Throw.IfNull(serviceType);
+
+        return
+            serviceKey is not null ? null :
+            serviceType == typeof(OpenAIClient) ? _openAIClient :
+            serviceType == typeof(ChatClient) ? _chatClient :
+            serviceType.IsInstanceOfType(this) ? this :
+            null;
+    }
 
     /// <inheritdoc />
     public async Task<ChatCompletion> CompleteAsync(

src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIEmbeddingGenerator.cs

@@ -11,6 +11,7 @@ using Microsoft.Shared.Diagnostics;
 using OpenAI;
 using OpenAI.Embeddings;
 
+#pragma warning disable S1067 // Expressions should not be too complex
 #pragma warning disable S3011 // Reflection should not be used to increase accessibility of classes, methods, or fields
 
 namespace Microsoft.Extensions.AI;
@@ -95,12 +96,17 @@ public sealed class OpenAIEmbeddingGenerator : IEmbeddingGenerator<string, Embed
     public EmbeddingGeneratorMetadata Metadata { get; }
 
     /// <inheritdoc />
-    public TService? GetService<TService>(object? key = null)
-        where TService : class
-        =>
-        typeof(TService) == typeof(OpenAIClient) ? (TService?)(object?)_openAIClient :
-        typeof(TService) == typeof(EmbeddingClient) ? (TService)(object)_embeddingClient :
-        this as TService;
+    public object? GetService(Type serviceType, object? serviceKey = null)
+    {
+        _ = Throw.IfNull(serviceType);
+
+        return
+            serviceKey is not null ? null :
+            serviceType == typeof(OpenAIClient) ? _openAIClient :
+            serviceType == typeof(EmbeddingClient) ? _embeddingClient :
+            serviceType.IsInstanceOfType(this) ? this :
+            null;
+    }
 
     /// <inheritdoc />
     public async Task<GeneratedEmbeddings<Embedding<float>>> GenerateAsync(IEnumerable<string> values, EmbeddingGenerationOptions? options = null, CancellationToken cancellationToken = default)

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/ChatCompletion/ChatClientExtensionsTests.cs

@@ -11,6 +11,12 @@ namespace Microsoft.Extensions.AI;
 
 public class ChatClientExtensionsTests
 {
+    [Fact]
+    public void GetService_InvalidArgs_Throws()
+    {
+        Assert.Throws<ArgumentNullException>("client", () => ChatClientExtensions.GetService<object>(null!));
+    }
+
     [Fact]
     public void CompleteAsync_InvalidArgs_Throws()
     {

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/ChatCompletion/DelegatingChatClientTests.cs

@@ -96,6 +96,14 @@ public class DelegatingChatClientTests
         Assert.False(await enumerator.MoveNextAsync());
     }
 
+    [Fact]
+    public void GetServiceThrowsForNullType()
+    {
+        using var inner = new TestChatClient();
+        using var delegating = new NoOpDelegatingChatClient(inner);
+        Assert.Throws<ArgumentNullException>("serviceType", () => delegating.GetService(null!));
+    }
+
     [Fact]
     public void GetServiceReturnsSelfIfCompatibleWithRequestAndKeyIsNull()
     {

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Embeddings/DelegatingEmbeddingGeneratorTests.cs

@@ -57,6 +57,14 @@ public class DelegatingEmbeddingGeneratorTests
         Assert.Same(expectedEmbedding, await resultTask);
     }
 
+    [Fact]
+    public void GetServiceThrowsForNullType()
+    {
+        using var inner = new TestEmbeddingGenerator();
+        using var delegating = new NoOpDelegatingEmbeddingGenerator(inner);
+        Assert.Throws<ArgumentNullException>("serviceType", () => delegating.GetService(null!));
+    }
+
     [Fact]
     public void GetServiceReturnsSelfIfCompatibleWithRequestAndKeyIsNull()
     {

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Embeddings/EmbeddingGeneratorExtensionsTests.cs

@@ -10,6 +10,13 @@ namespace Microsoft.Extensions.AI;
 
 public class EmbeddingGeneratorExtensionsTests
 {
+    [Fact]
+    public void GetService_InvalidArgs_Throws()
+    {
+        Assert.Throws<ArgumentNullException>("generator", () => EmbeddingGeneratorExtensions.GetService<object>(null!));
+        Assert.Throws<ArgumentNullException>("generator", () => EmbeddingGeneratorExtensions.GetService<string, Embedding<double>, object>(null!));
+    }
+
     [Fact]
     public async Task GenerateAsync_InvalidArgs_ThrowsAsync()
     {

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/TestChatClient.cs

@@ -26,9 +26,8 @@ public sealed class TestChatClient : IChatClient
     public IAsyncEnumerable<StreamingChatCompletionUpdate> CompleteStreamingAsync(IList<ChatMessage> chatMessages, ChatOptions? options = null, CancellationToken cancellationToken = default)
         => CompleteStreamingAsyncCallback!.Invoke(chatMessages, options, cancellationToken);
 
-    public TService? GetService<TService>(object? key = null)
-        where TService : class
-        => (TService?)GetServiceCallback!(typeof(TService), key);
+    public object? GetService(Type serviceType, object? serviceKey = null)
+        => GetServiceCallback!(serviceType, serviceKey);
 
     void IDisposable.Dispose()
     {

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/TestEmbeddingGenerator.cs

@@ -19,9 +19,8 @@ public sealed class TestEmbeddingGenerator : IEmbeddingGenerator<string, Embeddi
     public Task<GeneratedEmbeddings<Embedding<float>>> GenerateAsync(IEnumerable<string> values, EmbeddingGenerationOptions? options = null, CancellationToken cancellationToken = default)
         => GenerateAsyncCallback!.Invoke(values, options, cancellationToken);
 
-    public TService? GetService<TService>(object? key = null)
-        where TService : class
-        => (TService?)GetServiceCallback!(typeof(TService), key);
+    public object? GetService(Type serviceType, object? serviceKey = null)
+        => GetServiceCallback!(serviceType, serviceKey);
 
     void IDisposable.Dispose()
     {

test/Libraries/Microsoft.Extensions.AI.Integration.Tests/QuantizationEmbeddingGenerator.cs

@@ -29,10 +29,9 @@ internal sealed class QuantizationEmbeddingGenerator :
 
     void IDisposable.Dispose() => _floatService.Dispose();
 
-    public TService? GetService<TService>(object? key = null)
-        where TService : class =>
-        key is null && this is TService ? (TService?)(object)this :
-        _floatService.GetService<TService>(key);
+    public object? GetService(Type serviceType, object? serviceKey = null) =>
+        serviceKey is null && serviceType.IsInstanceOfType(this) ? this :
+        _floatService.GetService(serviceType, serviceKey);
 
     async Task<GeneratedEmbeddings<BinaryEmbedding>> IEmbeddingGenerator<string, BinaryEmbedding>.GenerateAsync(
         IEnumerable<string> values, EmbeddingGenerationOptions? options, CancellationToken cancellationToken)