CQRS with Minimal APIs sample

EventSourcing.NetCore.sln

@@ -323,6 +323,14 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "13-Projections.SingleStream
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "14-Projections.SingleStream.EventualConsistency", "Workshops\IntroductionToEventSourcing\Solved\14-Projections.SingleStream.EventualConsistency\14-Projections.SingleStream.EventualConsistency.csproj", "{A5A2A4CB-08F6-49AE-B044-DD9C5F8B0F48}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Warehouse.MinimalAPI", "Warehouse.MinimalAPI", "{005FC7CE-97BA-47F7-982E-63C46327F78C}"
+	ProjectSection(SolutionItems) = preProject
+		Sample\Warehouse.MinimalAPI\docker-compose.yml = Sample\Warehouse.MinimalAPI\docker-compose.yml
+		Sample\Warehouse.MinimalAPI\README.md = Sample\Warehouse.MinimalAPI\README.md
+	EndProjectSection
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Warehouse.Api", "Sample\Warehouse.MinimalAPI\Warehouse.Api\Warehouse.Api.csproj", "{723AD8CE-E3EF-40F6-9576-CCF2C3DB504E}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -737,6 +745,10 @@ Global
 		{A5A2A4CB-08F6-49AE-B044-DD9C5F8B0F48}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{A5A2A4CB-08F6-49AE-B044-DD9C5F8B0F48}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{A5A2A4CB-08F6-49AE-B044-DD9C5F8B0F48}.Release|Any CPU.Build.0 = Release|Any CPU
+		{723AD8CE-E3EF-40F6-9576-CCF2C3DB504E}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{723AD8CE-E3EF-40F6-9576-CCF2C3DB504E}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{723AD8CE-E3EF-40F6-9576-CCF2C3DB504E}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{723AD8CE-E3EF-40F6-9576-CCF2C3DB504E}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -867,6 +879,8 @@ Global
 		{2CA4B0B3-AF8B-4BD8-A18D-18EE1F93DE04} = {65F6E2BE-B2D4-4E56-B0CB-3062C4882B9E}
 		{7A990FD1-4935-4F85-912C-D4B870232856} = {65F6E2BE-B2D4-4E56-B0CB-3062C4882B9E}
 		{A5A2A4CB-08F6-49AE-B044-DD9C5F8B0F48} = {65F6E2BE-B2D4-4E56-B0CB-3062C4882B9E}
+		{005FC7CE-97BA-47F7-982E-63C46327F78C} = {A7186B6B-D56D-4AEF-B6B7-FAA827764C34}
+		{723AD8CE-E3EF-40F6-9576-CCF2C3DB504E} = {005FC7CE-97BA-47F7-982E-63C46327F78C}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {A5F55604-2FF3-43B7-B657-4F18E6E95D3B}

README.md

@@ -30,11 +30,12 @@ Tutorial, practical samples and other resources about Event Sourcing in .NET. Se
     - [6.2 Simple EventSourcing with EventStoreDB](#62-simple-eventsourcing-with-eventstoredb)
     - [6.3 ECommerce with EventStoreDB](#63-ecommerce-with-eventstoredb)
     - [6.5 Warehouse](#65-warehouse)
-    - [6.6 Event Versioning](#66-event-versioning)
-    - [6.7 Event Pipelines](#67-event-pipelines)
-    - [6.8 Meetings Management with Marten](#68-meetings-management-with-marten)
-    - [6.9 Cinema Tickets Reservations with Marten](#69-cinema-tickets-reservations-with-marten)
-    - [6.10 SmartHome IoT with Marten](#610-smarthome-iot-with-marten)
+    - [6.6 Warehouse Minimal API](#66-warehouse-minimal-api)
+    - [6.7 Event Versioning](#67-event-versioning)
+    - [6.8 Event Pipelines](#68-event-pipelines)
+    - [6.9 Meetings Management with Marten](#69-meetings-management-with-marten)
+    - [6.10 Cinema Tickets Reservations with Marten](#610-cinema-tickets-reservations-with-marten)
+    - [6.11 SmartHome IoT with Marten](#611-smarthome-iot-with-marten)
   - [7. Self-paced training Kits](#7-self-paced-training-kits)
     - [7.1 Introduction to Event Sourcing](#71-introduction-to-event-sourcing)
     - [7.2 Build your own Event Store](#72-build-your-own-event-store)
@@ -652,7 +653,13 @@ Samples are using CQRS architecture. They're sliced based on the business module
 - No Event Sourcing! Using Entity Framework to show that CQRS is not bounded to Event Sourcing or any type of storage,
 - No Aggregates! CQRS do not need DDD. Business logic can be handled in handlers.
 
-### 6.6 [Event Versioning](./Sample/EventsVersioning)
+### 6.6 [Warehouse Minimal API](./Sample/Warehouse.MinimalAPI/)
+Variation of the previous example, but:
+- using Minimal API,
+- example how to inject handlers in MediatR like style to decouple API from handlers.
+- 📝 Read more [CQRS is simpler than you think with .NET 6 and C# 10](https://event-driven.io/en/cqrs_is_simpler_than_you_think_with_net6/?utm_source=event_sourcing_net) 
+
+### 6.7 [Event Versioning](./Sample/EventsVersioning)
 Shows how to handle basic event schema versioning scenarios using event and stream transformations (e.g. upcasting):
 - [Simple mapping](./Sample/EventsVersioning/#simple-mapping)
   - [New not required property](./Sample/EventsVersioning/#new-not-required-property)
@@ -665,8 +672,9 @@ Shows how to handle basic event schema versioning scenarios using event and stre
 - [Events Transformations](./Sample/EventsVersioning/#events-transformations)
 - [Stream Transformation](./Sample/EventsVersioning/#stream-transformation)
 - [Summary](./Sample/EventsVersioning/#summary)
+- 📝 [Simple patterns for events schema versioning](https://event-driven.io/en/simple_events_versioning_patterns/?utm_source=event_sourcing_net) 
 
-### 6.7 [Event Pipelines](./Sample/EventPipelines)
+### 6.8 [Event Pipelines](./Sample/EventPipelines)
 Shows how to compose event handlers in the processing pipelines to:
 - filter events,
 - transform them,
@@ -676,21 +684,22 @@ Shows how to compose event handlers in the processing pipelines to:
 - allows using interfaces and classes if you want to,
 - can be used with Dependency Injection, but also without through builder,
 - integrates with MediatR if you want to.
+- 📝 Read more [How to build a simple event pipeline](https://event-driven.io/en/how_to_build_simple_event_pipeline/?utm_source=event_sourcing_net) 
 
-### 6.8 [Meetings Management with Marten](./Sample/MeetingsManagement/)
+### 6.9 [Meetings Management with Marten](./Sample/MeetingsManagement/)
 - typical Event Sourcing and CQRS flow,
 - DDD using Aggregates,
 - microservices example,
 - stores events to Marten,
 - Kafka as a messaging platform to integrate microservices,
 - read models handled in separate microservice and stored to other database (ElasticSearch)
 
-### 6.9 [Cinema Tickets Reservations with Marten](./Sample/Tickets/)
+### 6.10 [Cinema Tickets Reservations with Marten](./Sample/Tickets/)
 - typical Event Sourcing and CQRS flow,
 - DDD using Aggregates,
 - stores events to Marten.
 
-### 6.10 [SmartHome IoT with Marten](./Sample/AsyncProjections/)
+### 6.11 [SmartHome IoT with Marten](./Sample/AsyncProjections/)
 - typical Event Sourcing and CQRS flow,
 - DDD using Aggregates,
 - stores events to Marten,
@@ -762,6 +771,7 @@ Read also more on the **Event Sourcing** and **CQRS** topics in my [blog](https:
 -   📝 [How to slice the codebase effectively?](https://event-driven.io/en/how_to_slice_the_codebase_effectively/?utm_source=event_sourcing_net)
 -   📝 [Generic does not mean Simple?](https://event-driven.io/en/generic_does_not_mean_simple/?utm_source=event_sourcing_net)
 -   📝 [Can command return a value?](https://event-driven.io/en/can_command_return_a_value/?utm_source=event_sourcing_net)
+-   📝 [CQRS is simpler than you think with .NET 6 and C# 10](https://event-driven.io/en/cqrs_is_simpler_than_you_think_with_net6/?utm_source=event_sourcing_net)   
 -   📝 [How to register all CQRS handlers by convention](https://event-driven.io/en/how_to_register_all_mediatr_handlers_by_convention/?utm_source=event_sourcing_net)
 -   📝 [How to use ETag header for optimistic concurrency](https://event-driven.io/en/how_to_use_etag_header_for_optimistic_concurrency/?utm_source=event_sourcing_net)
 -   📝 [Dealing with Eventual Consistency and Idempotency in MongoDB projections](https://event-driven.io/en/dealing_with_eventual_consistency_and_idempotency_in_mongodb_projections/?utm_source=event_sourcing_net)
@@ -770,7 +780,8 @@ Read also more on the **Event Sourcing** and **CQRS** topics in my [blog](https:
 -   📝 [How to do snapshots in Marten?](https://event-driven.io/en/how_to_do_snapshots_in_Marten/?utm_source=event_sourcing_net)
 -   📝 [Integrating Marten with other systems](https://event-driven.io/en/integrating_Marten/?utm_source=event_sourcing_net)
 -   📝 [How to (not) do the events versioning?](https://event-driven.io/en/how_to_do_event_versioning/?utm_source=event_sourcing_net)
--   📝 [Simple patterns for events schema versioning](https://event-driven.io/en/simple_events_versioning_patterns/?utm_source=event_sourcing_net)
+-   📝 [Simple patterns for events schema versioning](https://event-driven.io/en/simple_events_versioning_patterns/?utm_source=event_sourcing_net) 
+-   📝 [How to build a simple event pipeline](https://event-driven.io/en/how_to_build_simple_event_pipeline/?utm_source=event_sourcing_net) 
 -   📝 [How to create projections of events for nested object structures?](https://event-driven.io/en/how_to_create_projections_of_events_for_nested_object_structures/?utm_source=event_sourcing_net)
 -   📝 [How to scale projections in the event-driven systems?](https://event-driven.io/en/how_to_scale_projections_in_the_event_driven_systems/?utm_source=event_sourcing_net)
 -   📝 [Immutable Value Objects are simpler and more useful than you think!](https://event-driven.io/en/immutable_value_objects/?utm_source=event_sourcing_net)

Sample/EventPipelines/README.md

@@ -9,6 +9,7 @@ Shows how to compose event handlers in the processing pipelines to:
 - allows using interfaces and classes if you want to,
 - can be used with Dependency Injection, but also without through builder,
 - integrates with MediatR if you want to.
+- 📝 Read more [How to build a simple event pipeline](https://event-driven.io/en/how_to_build_simple_event_pipeline/?utm_source=event_sourcing_net) 
 
 ## Overview
 

Sample/Warehouse.MinimalAPI/README.md

@@ -0,0 +1,7 @@
+# Warehouse Minimal API
+- CQRS flow using Minimal API,
+- example how to inject handlers in MediatR like style to decouple API from handling,
+- example of how and where to use C# Records, Nullable Reference Types, etc,
+- No Event Sourcing! Using Entity Framework to show that CQRS is not bounded to Event Sourcing or any type of storage,
+- No Aggregates! CQRS do not need DDD. Business logic can be handled in handlers.
+- 📝 Read more [CQRS is simpler than you think with .NET 6 and C# 10](https://event-driven.io/en/cqrs_is_simpler_than_you_think_with_net6/?utm_source=event_sourcing_net) 

Sample/Warehouse.MinimalAPI/Warehouse.Api/Core/Commands/ICommandHandler.cs

@@ -0,0 +1,43 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Warehouse.Api.Core.Commands;
+
+public interface ICommandHandler<in T>
+{
+    ValueTask Handle(T command, CancellationToken token);
+}
+
+public delegate ValueTask CommandHandler<in T>(T query, CancellationToken ct);
+
+public static class CommandHandlerConfiguration
+{
+    public static IServiceCollection AddCommandHandler<T, TCommandHandler>(
+        this IServiceCollection services,
+        Func<IServiceProvider, TCommandHandler>? configure = null
+    ) where TCommandHandler : class, ICommandHandler<T>
+    {
+        if (configure == null)
+        {
+            services.AddTransient<TCommandHandler, TCommandHandler>();
+            services.AddTransient<ICommandHandler<T>, TCommandHandler>();
+        }
+        else
+        {
+            services.AddTransient<TCommandHandler, TCommandHandler>(configure);
+            services.AddTransient<ICommandHandler<T>, TCommandHandler>(configure);
+        }
+
+        services
+            .AddTransient<Func<T, CancellationToken, ValueTask>>(
+                sp => sp.GetRequiredService<ICommandHandler<T>>().Handle
+            )
+            .AddTransient<CommandHandler<T>>(
+                sp => sp.GetRequiredService<ICommandHandler<T>>().Handle
+            );
+
+        return services;
+    }
+}

Sample/Warehouse.MinimalAPI/Warehouse.Api/Core/Entities/EntitiesExtensions.cs

@@ -0,0 +1,25 @@
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Warehouse.Api.Core.Entities;
+
+public static class EntitiesExtensions
+{
+    public static async ValueTask AddAndSave<T>(this DbContext dbContext, T entity, CancellationToken ct)
+        where T : notnull
+    {
+        await dbContext.AddAsync(entity, ct);
+        await dbContext.SaveChangesAsync(ct);
+    }
+
+    public static ValueTask<T?> Find<T, TId>(this DbContext dbContext, TId id, CancellationToken ct)
+        where T : class where TId : notnull
+        => dbContext.FindAsync<T>(new object[] {id}, ct);
+
+    public static IServiceCollection AddQueryable<T, TDbContext>(this IServiceCollection services)
+        where TDbContext : DbContext
+        where T : class =>
+        services.AddTransient(sp => sp.GetRequiredService<TDbContext>().Set<T>().AsNoTracking());
+}

Sample/Warehouse.MinimalAPI/Warehouse.Api/Core/Primitives/MappingExtensions.cs

@@ -0,0 +1,33 @@
+using System;
+
+namespace Warehouse.Api.Core.Primitives;
+
+internal static class MappingExtensions
+{
+    public static T AssertNotNull<T>(this T? value, string? paramName = null)
+        where T : struct
+    {
+        if (value == null)
+            throw new ArgumentNullException(paramName);
+
+        return (T)value;
+    }
+
+    public static string AssertNotEmpty(this string? value, string? paramName = null)
+        => !string.IsNullOrWhiteSpace(value) ? value : throw new ArgumentOutOfRangeException(paramName);
+
+    public static T AssertNotEmpty<T>(this T value, string? paramName = null)
+        where T : struct
+        => AssertNotEmpty((T?)value, paramName);
+
+    public static T AssertNotEmpty<T>(this T? value, string? paramName = null)
+        where T : struct
+    {
+        var notNullValue = value.AssertNotNull(paramName);
+
+        if(Equals(notNullValue, default(T)))
+            throw new ArgumentOutOfRangeException(paramName);
+
+        return notNullValue;
+    }
+}

Sample/Warehouse.MinimalAPI/Warehouse.Api/Core/Queries/IQueryHandler.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Warehouse.Api.Core.Queries;
+
+public interface IQueryHandler<in T, TResult>
+{
+    ValueTask<TResult> Handle(T query, CancellationToken ct);
+}
+
+public delegate ValueTask<TResult> QueryHandler<in T, TResult>(T query, CancellationToken ct);
+
+public static class QueryHandlerConfiguration
+{
+    public static IServiceCollection AddQueryHandler<T, TResult, TQueryHandler>(
+        this IServiceCollection services,
+        Func<IServiceProvider, TQueryHandler>? configure = null
+    ) where TQueryHandler : class, IQueryHandler<T, TResult>
+    {
+        if (configure == null)
+        {
+            services
+                .AddTransient<TQueryHandler, TQueryHandler>()
+                .AddTransient<IQueryHandler<T, TResult>, TQueryHandler>();
+        }
+        else
+        {
+            services
+                .AddTransient<TQueryHandler, TQueryHandler>(configure)
+                .AddTransient<IQueryHandler<T, TResult>, TQueryHandler>(configure);
+        }
+
+        services
+            .AddTransient<Func<T, CancellationToken, ValueTask<TResult>>>(
+                sp => sp.GetRequiredService<IQueryHandler<T, TResult>>().Handle
+            )
+            .AddTransient<QueryHandler<T, TResult>>(
+                sp => sp.GetRequiredService<IQueryHandler<T, TResult>>().Handle
+            );
+
+        return services;
+    }
+}

Sample/Warehouse.MinimalAPI/Warehouse.Api/Migrations/20211214161109_Initial.cs

@@ -0,0 +1,33 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Warehouse.Api.Migrations
+{
+    public partial class Initial : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "Product",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uuid", nullable: false),
+                    Sku_Value = table.Column<string>(type: "text", nullable: false),
+                    Name = table.Column<string>(type: "text", nullable: false),
+                    Description = table.Column<string>(type: "text", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_Product", x => x.Id);
+                });
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "Product");
+        }
+    }
+}