Query bus feature

Library/Extensions/CommandHandlersRegister.cs

@@ -2,16 +2,16 @@
 
 namespace Library.Command
 {
-    public static class CommandHandlersRegister
+    public static class CommandQueryHandlersRegister
     {
-        public static IServiceCollection AddCommandHandlers(this IServiceCollection services, Type assemblyType)
+        public static IServiceCollection AddCommandQueryHandlers(this IServiceCollection services, Type assemblyType, Type commandQueryHandler)
         {
             var handlers = assemblyType.Assembly.GetTypes()
-                .Where(t => t.GetInterfaces().Any(i => i.IsGenericType && i.GetGenericTypeDefinition() == typeof(ICommandHandler<>)));
+                .Where(t => t.GetInterfaces().Any(i => i.IsGenericType && i.GetGenericTypeDefinition() == commandQueryHandler));
 
             foreach (var handler in handlers)
                 services.AddScoped(handler.GetInterfaces()
-                    .First(i => i.IsGenericType && i.GetGenericTypeDefinition() == typeof(ICommandHandler<>)), handler);
+                    .First(i => i.IsGenericType && i.GetGenericTypeDefinition() == commandQueryHandler), handler);
 
             return services;
         }

Library/Query/IQueryBus.cs

@@ -0,0 +1,7 @@
+namespace Library.Query
+{
+    public interface IQueryBus
+    {
+        Task<TResponse> Dispatch<TRequest, TResponse>(TRequest command);
+    }
+}

Library/Query/IQueryHandler.cs

@@ -0,0 +1,7 @@
+namespace Library.Query
+{
+    public interface IQueryHandler<TRequest, TResponse>
+    {
+        Task<TResponse> Handle(TRequest command);
+    }
+}

Library/Query/QueryBus.cs

@@ -0,0 +1,19 @@
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Library.Query
+{
+    public class QueryBus : IQueryBus
+    {
+        private readonly IServiceProvider _provider;
+        public QueryBus(IServiceProvider provider)
+        {
+            _provider = provider;
+        }
+
+        public async Task<TResponse> Dispatch<TRequest, TResponse>(TRequest query)
+        {
+            var service = _provider.GetRequiredService(typeof(IQueryHandler<TRequest, TResponse>)) as IQueryHandler<TRequest, TResponse>;
+            return await service.Handle(query);
+        }
+    }
+}

WebApi/Application/Query/ProductQueryRequest.cs

@@ -0,0 +1,7 @@
+namespace WebApi.Application.Query
+{
+    public class ProductQueryRequest
+    {
+        public int Id { get; set; }
+    }
+}

WebApi/Application/Query/ProductQueryResponse.cs

@@ -0,0 +1,7 @@
+namespace WebApi.Application.Query
+{
+    public class ProductQueryResponse
+    {
+        public string ProductName { get; set; }
+    }
+}

WebApi/Application/QueryHandlers/ProductQueryHandler.cs

@@ -0,0 +1,21 @@
+using Library.Query;
+using WebApi.Application.Query;
+
+namespace WebApi.Application.QueryHandler
+{
+    public class ProductQueryHandler : IQueryHandler<ProductQueryRequest, ProductQueryResponse>
+    {
+        public async Task<ProductQueryResponse> Handle(ProductQueryRequest query)
+        {
+            //Query from database
+            //_repository.GetProductName(query.Id);
+
+            var productName = "Laptop";
+
+            return new ProductQueryResponse
+            {
+                ProductName = productName,
+            };
+        }
+    }
+}

WebApi/Controllers/HomeController.cs

@@ -1,19 +1,23 @@
 using Library.Command;
+using Library.Query;
 using Microsoft.AspNetCore.Mvc;
 using System.Diagnostics;
 using WebApi.Application.Command;
+using WebApi.Application.Query;
 using WebApi.Models;
 
 namespace WebApi.Controllers
 {
     public class HomeController : Controller
     {
         private readonly ILogger<HomeController> _logger;
-        private readonly ICommandBus _bus;
-        public HomeController(ILogger<HomeController> logger, ICommandBus bus)
+        private readonly ICommandBus _commandBus;
+        private readonly IQueryBus _queryBus;
+        public HomeController(ILogger<HomeController> logger, ICommandBus commandBus, IQueryBus queryBus)
         {
             _logger = logger;
-            _bus = bus;
+            _commandBus = commandBus;
+            _queryBus = queryBus;
         }
 
         public IActionResult Index()
@@ -24,7 +28,14 @@ public IActionResult Index()
                 Name = "Laptop;"
             };
 
-            _bus.Dispatch(productCommand);
+            _commandBus.Dispatch(productCommand);
+
+            var productQueryRequest = new ProductQueryRequest
+            {
+                Id = 1
+            };
+
+            _queryBus.Dispatch<ProductQueryRequest, ProductQueryResponse>(productQueryRequest);
 
             return View();
         }

WebApi/Program.cs

@@ -1,11 +1,14 @@
 using Library.Command;
+using Library.Query;
 
 var builder = WebApplication.CreateBuilder(args);
 
 builder.Services.AddControllersWithViews();
 
-builder.Services.AddCommandHandlers(typeof(Program));
+builder.Services.AddCommandQueryHandlers(typeof(Program), typeof(ICommandHandler<>));
+builder.Services.AddCommandQueryHandlers(typeof(Program), typeof(IQueryHandler<,>));
 builder.Services.AddScoped<ICommandBus, CommandBus>();
+builder.Services.AddScoped<IQueryBus, QueryBus>();
 
 var app = builder.Build();