Merge pull request #6 from EventStore/cqrs_flow/dotnet/refactoring

Refactoring of the CQRS Flow .NET example based on the feedback

CQRS_Flow/.NET/Carts/Carts.Api/Controllers/CartsController.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Threading;
 using System.Threading.Tasks;
 using Carts.Api.Requests.Carts;
 using Carts.Carts.GettingCartAtVersion;
@@ -32,7 +33,7 @@ public CartsController(
         }
 
         [HttpPost]
-        public async Task<IActionResult> InitializeCart([FromBody] InitializeCartRequest? request)
+        public async Task<IActionResult> InitializeCart([FromBody] InitializeCartRequest? request, CancellationToken ct)
         {
             if (request == null)
                 throw new ArgumentNullException(nameof(request));
@@ -44,13 +45,13 @@ public async Task<IActionResult> InitializeCart([FromBody] InitializeCartRequest
                 request.ClientId
             );
 
-            await commandBus.Send(command);
+            await commandBus.Send(command, ct);
 
             return Created("api/Carts", cartId);
         }
 
         [HttpPost("{id}/products")]
-        public async Task<IActionResult> AddProduct(Guid id, [FromBody] AddProductRequest? request)
+        public async Task<IActionResult> AddProduct(Guid id, [FromBody] AddProductRequest? request, CancellationToken ct)
         {
             if (request == null)
                 throw new ArgumentNullException(nameof(request));
@@ -63,13 +64,13 @@ public async Task<IActionResult> AddProduct(Guid id, [FromBody] AddProductReques
                 )
             );
 
-            await commandBus.Send(command);
+            await commandBus.Send(command, ct);
 
             return Ok();
         }
 
         [HttpDelete("{id}/products")]
-        public async Task<IActionResult> RemoveProduct(Guid id, [FromBody] RemoveProductRequest? request)
+        public async Task<IActionResult> RemoveProduct(Guid id, [FromBody] RemoveProductRequest? request, CancellationToken ct)
         {
             if (request == null)
                 throw new ArgumentNullException(nameof(request));
@@ -83,49 +84,49 @@ public async Task<IActionResult> RemoveProduct(Guid id, [FromBody] RemoveProduct
                 )
             );
 
-            await commandBus.Send(command);
+            await commandBus.Send(command, ct);
 
             return Ok();
         }
 
         [HttpPut("{id}/confirmation")]
-        public async Task<IActionResult> ConfirmCart(Guid id)
+        public async Task<IActionResult> ConfirmCart(Guid id, CancellationToken ct)
         {
             var command = Carts.ConfirmingCart.ConfirmCart.Create(
                 id
             );
 
-            await commandBus.Send(command);
+            await commandBus.Send(command, ct);
 
             return Ok();
         }
 
         [HttpGet("{id}")]
-        public Task<CartDetails> Get(Guid id)
+        public Task<CartDetails> Get(Guid id, CancellationToken ct)
         {
-            return queryBus.Send<GetCartById, CartDetails>(GetCartById.Create(id));
+            return queryBus.Send<GetCartById, CartDetails>(GetCartById.Create(id), ct);
         }
 
         [HttpGet]
-        public Task<IReadOnlyList<CartShortInfo>> Get([FromQuery] int pageNumber = 1, [FromQuery] int pageSize = 20)
+        public Task<IReadOnlyList<CartShortInfo>> Get(CancellationToken ct, [FromQuery] int pageNumber = 1, [FromQuery] int pageSize = 20)
         {
-            return queryBus.Send<GetCarts, IReadOnlyList<CartShortInfo>>(GetCarts.Create(pageNumber, pageSize));
+            return queryBus.Send<GetCarts, IReadOnlyList<CartShortInfo>>(GetCarts.Create(pageNumber, pageSize), ct);
         }
 
 
         [HttpGet("{id}/history")]
-        public Task<IReadOnlyList<CartHistory>> GetHistory(Guid id)
+        public Task<IReadOnlyList<CartHistory>> GetHistory(Guid id, CancellationToken ct)
         {
-            return queryBus.Send<GetCartHistory, IReadOnlyList<CartHistory>>(GetCartHistory.Create(id));
+            return queryBus.Send<GetCartHistory, IReadOnlyList<CartHistory>>(GetCartHistory.Create(id), ct);
         }
 
         [HttpGet("{id}/versions")]
-        public Task<CartDetails> GetVersion(Guid id, [FromQuery] GetCartAtVersion? query)
+        public Task<CartDetails> GetVersion(Guid id, [FromQuery] GetCartAtVersion? query, CancellationToken ct)
         {
             if (query == null)
                 throw new ArgumentNullException(nameof(query));
 
-            return queryBus.Send<GetCartAtVersion, CartDetails>(GetCartAtVersion.Create(id, query.Version));
+            return queryBus.Send<GetCartAtVersion, CartDetails>(GetCartAtVersion.Create(id, query.Version), ct);
         }
     }
 }

CQRS_Flow/.NET/Carts/Carts.Tests/Builders/CartBuilder.cs

@@ -9,7 +9,7 @@ namespace Carts.Tests.Builders
 {
     internal class CartBuilder
     {
-        private readonly Queue<IEvent> eventsToApply = new();
+        private readonly Queue<object> eventsToApply = new();
 
         public CartBuilder Initialized()
         {

CQRS_Flow/.NET/Carts/Carts/Carts/AddingProduct/AddProduct.cs

@@ -5,11 +5,10 @@
 using Carts.Pricing;
 using Core.Commands;
 using Core.Repositories;
-using MediatR;
 
 namespace Carts.Carts.AddingProduct
 {
-    public class AddProduct: ICommand
+    public class AddProduct
     {
         public Guid CartId { get; }
 
@@ -44,7 +43,7 @@ IProductPriceCalculator productPriceCalculator
             this.productPriceCalculator = productPriceCalculator;
         }
 
-        public Task<Unit> Handle(AddProduct command, CancellationToken cancellationToken)
+        public Task Handle(AddProduct command, CancellationToken cancellationToken)
         {
             return cartRepository.GetAndUpdate(
                 command.CartId,

CQRS_Flow/.NET/Carts/Carts/Carts/AddingProduct/ProductAdded.cs

@@ -4,7 +4,7 @@
 
 namespace Carts.Carts.AddingProduct
 {
-    public class ProductAdded: IEvent
+    public class ProductAdded
     {
         public Guid CartId { get; }
 

CQRS_Flow/.NET/Carts/Carts/Carts/Config.cs

@@ -13,7 +13,6 @@
 using Core.EventStoreDB.Repository;
 using Core.Queries;
 using Core.Repositories;
-using MediatR;
 using Microsoft.Extensions.DependencyInjection;
 
 namespace Carts.Carts

CQRS_Flow/.NET/Carts/Carts/Carts/ConfirmingCart/CartConfirmed.cs

@@ -3,7 +3,7 @@
 
 namespace Carts.Carts.ConfirmingCart
 {
-    public class CartConfirmed: IEvent
+    public class CartConfirmed
     {
         public Guid CartId { get; }
 

CQRS_Flow/.NET/Carts/Carts/Carts/ConfirmingCart/ConfirmCart.cs

@@ -3,11 +3,10 @@
 using System.Threading.Tasks;
 using Core.Commands;
 using Core.Repositories;
-using MediatR;
 
 namespace Carts.Carts.ConfirmingCart
 {
-    public class ConfirmCart: ICommand
+    public class ConfirmCart
     {
         public Guid CartId { get; }
 
@@ -37,7 +36,7 @@ IRepository<Cart> cartRepository
             this.cartRepository = cartRepository;
         }
 
-        public Task<Unit> Handle(ConfirmCart command, CancellationToken cancellationToken)
+        public Task Handle(ConfirmCart command, CancellationToken cancellationToken)
         {
             return cartRepository.GetAndUpdate(
                 command.CartId,

CQRS_Flow/.NET/Carts/Carts/Carts/GettingCartAtVersion/GetCartAtVersion.cs

@@ -9,7 +9,7 @@
 
 namespace Carts.Carts.GettingCartAtVersion
 {
-    public class GetCartAtVersion : IQuery<CartDetails>
+    public class GetCartAtVersion
     {
         public Guid CartId { get; }
         public ulong Version { get; }

CQRS_Flow/.NET/Carts/Carts/Carts/GettingCartById/GetCartById.cs

@@ -8,7 +8,7 @@
 
 namespace Carts.Carts.GettingCartById
 {
-    public class GetCartById : IQuery<CartDetails>
+    public class GetCartById
     {
         public Guid CartId { get; }
 

CQRS_Flow/.NET/Carts/Carts/Carts/GettingCartHistory/GetCartHistory.cs

@@ -8,7 +8,7 @@
 
 namespace Carts.Carts.GettingCartHistory
 {
-    public class GetCartHistory: IQuery<IReadOnlyList<CartHistory>>
+    public class GetCartHistory
     {
         public Guid CartId { get; }
         public int PageNumber { get; }

CQRS_Flow/.NET/Carts/Carts/Carts/GettingCarts/GetCarts.cs

@@ -8,7 +8,7 @@
 
 namespace Carts.Carts.GettingCarts
 {
-    public class GetCarts : IQuery<IReadOnlyList<CartShortInfo>>
+    public class GetCarts
     {
         public int PageNumber { get; }
         public int PageSize { get; }

CQRS_Flow/.NET/Carts/Carts/Carts/InitializingCart/CartInitialized.cs

@@ -3,7 +3,7 @@
 
 namespace Carts.Carts.InitializingCart
 {
-    public class CartInitialized: IEvent
+    public class CartInitialized
     {
         public Guid CartId { get; }
 

CQRS_Flow/.NET/Carts/Carts/Carts/InitializingCart/InitializeCart.cs

@@ -3,11 +3,10 @@
 using System.Threading.Tasks;
 using Core.Commands;
 using Core.Repositories;
-using MediatR;
 
 namespace Carts.Carts.InitializingCart
 {
-    public class InitializeCart: ICommand
+    public class InitializeCart
     {
         public Guid CartId { get; }
 
@@ -42,13 +41,11 @@ IRepository<Cart> cartRepository
             this.cartRepository = cartRepository;
         }
 
-        public async Task<Unit> Handle(InitializeCart command, CancellationToken cancellationToken)
+        public async Task Handle(InitializeCart command, CancellationToken cancellationToken)
         {
             var cart = Cart.Initialize(command.CartId, command.ClientId);
 
             await cartRepository.Add(cart, cancellationToken);
-
-            return Unit.Value;
         }
     }
 }

CQRS_Flow/.NET/Carts/Carts/Carts/RemovingProduct/ProductRemoved.cs

@@ -1,10 +1,9 @@
 using System;
 using Carts.Carts.Products;
-using Core.Events;
 
 namespace Carts.Carts.RemovingProduct
 {
-    public class ProductRemoved: IEvent
+    public class ProductRemoved
     {
         public Guid CartId { get; }
 

CQRS_Flow/.NET/Carts/Carts/Carts/RemovingProduct/RemoveProduct.cs

@@ -4,11 +4,10 @@
 using Carts.Carts.Products;
 using Core.Commands;
 using Core.Repositories;
-using MediatR;
 
 namespace Carts.Carts.RemovingProduct
 {
-    public class RemoveProduct: ICommand
+    public class RemoveProduct
     {
         public Guid CartId { get; }
 
@@ -38,7 +37,7 @@ IRepository<Cart> cartRepository
             this.cartRepository = cartRepository;
         }
 
-        public Task<Unit> Handle(RemoveProduct command, CancellationToken cancellationToken)
+        public Task Handle(RemoveProduct command, CancellationToken cancellationToken)
         {
             return cartRepository.GetAndUpdate(
                 command.CartId,

CQRS_Flow/.NET/Core/Core.ElasticSearch/Projections/ElasticSearchProjection.cs

@@ -4,15 +4,14 @@
 using Core.ElasticSearch.Indices;
 using Core.Events;
 using Core.Projections;
-using MediatR;
 using Microsoft.Extensions.DependencyInjection;
 using Nest;
 
 namespace Core.ElasticSearch.Projections
 {
     public class ElasticSearchProjection<TEvent, TView> : IEventHandler<TEvent>
         where TView : class, IProjection
-        where TEvent : IEvent
+        where TEvent : notnull
     {
         private readonly IElasticClient elasticClient;
         private readonly Func<TEvent, string> getId;
@@ -35,7 +34,7 @@ public async Task Handle(TEvent @event, CancellationToken ct)
 
             entity.When(@event);
 
-            var result = await elasticClient.UpdateAsync<TView>(id,
+            await elasticClient.UpdateAsync<TView>(id,
                 u => u.Doc(entity).Upsert(entity).Index(IndexNameMapper.ToIndexName<TView>()),
                 ct
             );
@@ -47,9 +46,9 @@ public static class ElasticSearchProjectionConfig
         public static IServiceCollection Project<TEvent, TView>(this IServiceCollection services,
             Func<TEvent, string> getId)
             where TView : class, IProjection
-            where TEvent : IEvent
+            where TEvent : notnull
         {
-            services.AddTransient<INotificationHandler<TEvent>>(sp =>
+            services.AddTransient<IEventHandler<TEvent>>(sp =>
             {
                 var session = sp.GetRequiredService<IElasticClient>();
 
@@ -59,4 +58,4 @@ public static IServiceCollection Project<TEvent, TView>(this IServiceCollection
             return services;
         }
     }
-}
+}

CQRS_Flow/.NET/Core/Core.EventStoreDB/Serialization/EventStoreDBSerializer.cs

@@ -18,7 +18,7 @@ public static object Deserialize(this ResolvedEvent resolvedEvent)
             return JsonConvert.DeserializeObject(Encoding.UTF8.GetString(resolvedEvent.Event.Data.Span), eventType!)!;
         }
 
-        public static EventData ToJsonEventData(this IEvent @event) =>
+        public static EventData ToJsonEventData(this object @event) =>
             new(
                 Uuid.NewUuid(),
                 EventTypeMapper.ToName(@event.GetType()),

CQRS_Flow/.NET/Core/Core.EventStoreDB/Subscriptions/EventStoreDBSubscriptionCheckpointRepository.cs

@@ -8,7 +8,7 @@
 
 namespace Core.EventStoreDB.Subscriptions
 {
-    public record CheckpointStored(string SubscriptionId, ulong? Position, DateTime CheckpointedAt): IEvent;
+    public record CheckpointStored(string SubscriptionId, ulong? Position, DateTime CheckpointedAt);
 
     public class EventStoreDBSubscriptionCheckpointRepository: ISubscriptionCheckpointRepository
     {

CQRS_Flow/.NET/Core/Core.EventStoreDB/Subscriptions/SubscribeToAllBackgroundWorker.cs

@@ -125,7 +125,7 @@ private async Task HandleEvent(StreamSubscription subscription, ResolvedEvent re
                     scope.ServiceProvider.GetRequiredService<IEventBus>();
 
                 // publish event to internal event bus
-                await eventBus.Publish((IEvent)resolvedEvent.Deserialize());
+                await eventBus.Publish(resolvedEvent.Deserialize(), ct);
 
                 await checkpointRepository.Store(subscriptionId, resolvedEvent.Event.Position.CommitPosition, ct);
             }

CQRS_Flow/.NET/Core/Core.Testing/AggregateExtensions.cs

@@ -6,7 +6,7 @@ namespace Core.Testing
 {
     public static class AggregateExtensions
     {
-        public static T? PublishedEvent<T>(this IAggregate aggregate) where T : class, IEvent
+        public static T? PublishedEvent<T>(this IAggregate aggregate) where T : class
         {
             return aggregate.DequeueUncommittedEvents().LastOrDefault() as T;
         }

CQRS_Flow/.NET/Core/Core.Testing/Core.Testing.csproj

@@ -12,7 +12,7 @@
         <PackageReference Include="Microsoft.Extensions.Configuration.FileExtensions" Version="5.0.0" />
         <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="5.0.0" />
         <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
-        <PackageReference Include="NSubstitute" Version="4.2.2" />
+        <PackageReference Include="FluentAssertions" Version="5.10.3" />
         <PackageReference Include="xunit" Version="2.4.1" />
         <PackageReference Include="Microsoft.AspNetCore.TestHost" Version="5.0.7" />
     </ItemGroup>

CQRS_Flow/.NET/Core/Core.Testing/TestContext.cs

@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Net.Http;
-using MediatR;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.TestHost;
 using Microsoft.Extensions.DependencyInjection;