feat: create request projects for basic CQRS

src/request.dispatcher/RequestDispatcherBuilderExtensions.cs

@@ -0,0 +1,174 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Reflection;
+using System.Runtime.CompilerServices;
+
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+
+using static Geekeey.Request.Dispatcher.RequestDispatcherOptions;
+
+namespace Geekeey.Request.Dispatcher;
+
+/// <summary>
+/// Provides extension methods for configuring <see cref="IRequestDispatcherBuilder"/>
+/// with additional capabilities such as searching and registering request handlers in assemblies or adding types directly.
+/// </summary>
+public static class RequestDispatcherBuilderExtensions
+{
+	/// <summary>
+	/// Searches for request handler types within the specified assembly and adds them to the request dispatcher
+	/// configuration.
+	/// </summary>
+	/// <remarks>
+	/// Prefer the generated <c>Add&lt;Name&gt;(builder)</c> extensions for assemblies that directly reference
+	/// <c>Geekeey.Request.Dispatcher</c>. This runtime scanning API remains supported, but nested request handlers are rejected
+	/// during registration and generated registration should not be mixed with <see cref="SearchHandlerInAssembly(IRequestDispatcherBuilder, Assembly)"/>
+	/// for the same assembly.
+	/// </remarks>
+	/// <param name="builder">The <see cref="IRequestDispatcherBuilder"/> to configure.</param>
+	/// <param name="assembly">The assembly to search for request handler types.</param>
+	/// <returns>The <see cref="IRequestDispatcherBuilder"/> instance for further configuration.</returns>
+	public static IRequestDispatcherBuilder SearchHandlerInAssembly(this IRequestDispatcherBuilder builder, Assembly assembly)
+	{
+		ArgumentNullException.ThrowIfNull(builder);
+
+		var exports = assembly.GetTypes()
+			.Where(type => type is { IsClass: true, IsAbstract: false })
+			.Where(IsRequestHandlerImplementationType);
+
+		builder.Add(exports);
+
+		return builder;
+	}
+
+	/// <summary>
+	/// Searches for request handler types within the specified assembly and adds them to the request dispatcher
+	/// configuration with the given service lifetime.
+	/// </summary>
+	/// <remarks>
+	/// Prefer the generated <c>Add&lt;Name&gt;(builder, lifetime)</c> extensions for assemblies that directly reference
+	/// <c>Geekeey.Request.Dispatcher</c>. This runtime scanning API remains supported, but nested request handlers are rejected
+	/// during registration and generated registration should not be mixed with <see cref="SearchHandlerInAssembly(IRequestDispatcherBuilder, Assembly, ServiceLifetime)"/>
+	/// for the same assembly.
+	/// </remarks>
+	/// <param name="builder">The <see cref="IRequestDispatcherBuilder"/> to configure.</param>
+	/// <param name="assembly">The assembly to search for request handler types.</param>
+	/// <param name="lifetime">The lifetime with which the request handlers are registered in the dependency injection container.</param>
+	/// <returns>The <see cref="IRequestDispatcherBuilder"/> instance for further configuration.</returns>
+	public static IRequestDispatcherBuilder SearchHandlerInAssembly(this IRequestDispatcherBuilder builder, Assembly assembly, ServiceLifetime lifetime)
+	{
+		ArgumentNullException.ThrowIfNull(builder);
+
+		var exports = assembly.GetTypes()
+			.Where(type => type is { IsClass: true, IsAbstract: false })
+			.Where(IsRequestHandlerImplementationType);
+
+		builder.Add(exports, lifetime);
+
+		return builder;
+	}
+
+	/// <summary>
+	/// Adds the specified type to the request dispatcher configuration for inspection.
+	/// </summary>
+	/// <param name="builder">The <see cref="IRequestDispatcherBuilder"/> to configure.</param>
+	/// <param name="type">The type to be added to the request dispatcher configuration.</param>
+	/// <returns>The <see cref="IRequestDispatcherBuilder"/> instance for further configuration.</returns>
+	public static IRequestDispatcherBuilder Add(this IRequestDispatcherBuilder builder, Type type)
+	{
+		ArgumentNullException.ThrowIfNull(builder);
+		ValidateNoNestedRequestHandlers([type]);
+
+		builder.Services.AddOptions<RequestDispatcherOptions>()
+			.Configure(options => options.Inspect([type]));
+
+		return builder;
+	}
+
+	/// <summary>
+	/// Adds the specified type to the request dispatcher configuration.
+	/// This also adds the type to the service collection with the specified lifetime,
+	/// allowing it to be resolved as a dependency in request handlers and behaviors.
+	/// </summary>
+	/// <param name="builder">The <see cref="IRequestDispatcherBuilder"/> used to configure the request dispatcher.</param>
+	/// <param name="type">The type to be added to the request dispatcher configuration.</param>
+	/// <param name="lifetime">The lifetime scope of the type in the service container.</param>
+	/// <returns>The <see cref="IRequestDispatcherBuilder"/> instance for further configuration.</returns>
+	public static IRequestDispatcherBuilder Add(this IRequestDispatcherBuilder builder, Type type, ServiceLifetime lifetime)
+	{
+		ArgumentNullException.ThrowIfNull(builder);
+		ValidateNoNestedRequestHandlers([type]);
+
+		builder.Services.AddOptions<RequestDispatcherOptions>()
+			.Configure(options => options.Inspect([type]));
+
+		builder.Services.Add(new ServiceDescriptor(type, type, lifetime));
+
+		return builder;
+	}
+
+	/// <summary>
+	/// Adds the specified collection of types to the request dispatcher configuration for inspection.
+	/// </summary>
+	/// <param name="builder">The <see cref="IRequestDispatcherBuilder"/> to configure.</param>
+	/// <param name="type">The collection of types to be added to the request dispatcher configuration.</param>
+	/// <returns>The <see cref="IRequestDispatcherBuilder"/> instance for further configuration.</returns>
+	public static IRequestDispatcherBuilder Add(this IRequestDispatcherBuilder builder, IEnumerable<Type> type)
+	{
+		ArgumentNullException.ThrowIfNull(builder);
+
+		var types = ValidateNoNestedRequestHandlers([.. type]);
+
+		builder.Services.AddOptions<RequestDispatcherOptions>()
+			.Configure(options => options.Inspect(types));
+
+		return builder;
+	}
+
+	/// <summary>
+	/// Adds the specified collection of types to the request dispatcher configuration for inspection.
+	/// This also adds the specified collection of types to the service collection with the specified lifetime,
+	/// allowing it to be resolved as a dependency in request handlers and behaviors.
+	/// </summary>
+	/// <param name="builder">The <see cref="IRequestDispatcherBuilder"/> to configure.</param>
+	/// <param name="type">The collection of types to be added to the request dispatcher configuration.</param>
+	/// <param name="lifetime">The lifetime scope of the types in the service container.</param>
+	/// <returns>The <see cref="IRequestDispatcherBuilder"/> instance for further configuration.</returns>
+	public static IRequestDispatcherBuilder Add(this IRequestDispatcherBuilder builder, IEnumerable<Type> type, ServiceLifetime lifetime)
+	{
+		ArgumentNullException.ThrowIfNull(builder);
+
+		var types = ValidateNoNestedRequestHandlers([.. type]);
+
+		builder.Services.AddOptions<RequestDispatcherOptions>()
+			.Configure(options => options.Inspect(types));
+
+		builder.Services.Add(types.Select(export => new ServiceDescriptor(export, export, lifetime)));
+
+		return builder;
+	}
+
+	private static IReadOnlyCollection<Type> ValidateNoNestedRequestHandlers(IReadOnlyCollection<Type> types, [CallerMemberName] string? invoker = null)
+	{
+		var nestedHandlers = types
+			.Where(type => type is { IsClass: true, IsAbstract: false, IsNested: true })
+			.Where(IsRequestHandlerImplementationType)
+			.Select(type => type.FullName ?? type.Name)
+			.OrderBy(static name => name, StringComparer.Ordinal)
+			.ToArray();
+
+		if (nestedHandlers.Length > 0)
+		{
+			throw new InvalidOperationException($"Nested request handlers are not supported by {invoker}: {string.Join(", ", nestedHandlers)}");
+		}
+
+		return types;
+	}
+
+	private static bool IsRequestHandlerImplementationType(Type type)
+	{
+		return type.GetInterfaces().Any(IsRequestHandlerType);
+	}
+}