feat: create request projects for basic CQRS

src/request.dispatcher/ScalarRequestInvoker.cs

@@ -0,0 +1,47 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
+
+namespace Geekeey.Request.Dispatcher;
+
+internal abstract class ScalarRequestInvoker
+{
+	public abstract Task<object?> HandleAsync(object request, IServiceProvider serviceProvider, CancellationToken cancellationToken);
+}
+
+internal abstract class ScalarRequestInvoker<TResponse> : ScalarRequestInvoker
+{
+	public abstract Task<TResponse> HandleAsync(IScalarRequest<TResponse> request, IServiceProvider serviceProvider, CancellationToken cancellationToken);
+}
+
+internal sealed class ScalarRequestInvoker<TRequest, TResponse> : ScalarRequestInvoker<TResponse>
+	where TRequest : IScalarRequest<TResponse>
+{
+	public override async Task<object?> HandleAsync(object request, IServiceProvider serviceProvider, CancellationToken cancellationToken)
+	{
+		return await HandleAsync((IScalarRequest<TResponse>)request, serviceProvider, cancellationToken).ConfigureAwait(false);
+	}
+
+	public override Task<TResponse> HandleAsync(IScalarRequest<TResponse> request, IServiceProvider serviceProvider, CancellationToken cancellationToken)
+	{
+		var options = serviceProvider.GetRequiredService<IOptions<RequestDispatcherOptions>>().Value;
+
+		var pipeline = options.GetRequestBehaviors<IScalarRequestBehavior<TRequest, TResponse>>(serviceProvider)
+			.Reverse()
+			.Aggregate((ScalarHandlerDelegate<TResponse>)Head, Chain);
+
+		return pipeline(request, cancellationToken);
+
+		static ScalarHandlerDelegate<TResponse> Chain(ScalarHandlerDelegate<TResponse> next, IScalarRequestBehavior<TRequest, TResponse> filter)
+		{
+			return (req, ct) => filter.HandleAsync((TRequest)req, next, ct);
+		}
+
+		Task<TResponse> Head(IScalarRequest<TResponse> r, CancellationToken ct)
+		{
+			return options.GetRequestHandlers<IScalarRequestHandler<TRequest, TResponse>>(serviceProvider).First().HandleAsync((TRequest)r, ct);
+		}
+	}
+}