Use MediatR and refactor cashier, barista and UI

There's still a big change coming to the UI so it's easier for the cashier to use.

Directory.Packages.props

@@ -10,34 +10,36 @@
     <PackageVersion Include="Aspire.RabbitMQ.Client" Version="8.0.1" />
     <PackageVersion Include="AspNetCore.HealthChecks.EventStore.gRPC" Version="6.0.1" />
     <PackageVersion Include="AspNetCore.HealthChecks.Rabbitmq" Version="8.0.1" />
+    <PackageVersion Include="MediatR" Version="12.2.0" />
+    <PackageVersion Include="Microsoft.AspNetCore.Mvc.Testing" Version="8.0.5" />
     <PackageVersion Include="Microsoft.Extensions.Http.Resilience" Version="8.5.0" />
     <PackageVersion Include="Microsoft.Extensions.ServiceDiscovery" Version="8.0.1" />
     <PackageVersion Include="Microsoft.Extensions.TimeProvider.Testing" Version="8.5.0" />
     <PackageVersion Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.8.1" />
     <PackageVersion Include="OpenTelemetry.Extensions.Hosting" Version="1.8.1" />
     <PackageVersion Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.8.1" />
     <PackageVersion Include="OpenTelemetry.Instrumentation.Http" Version="1.8.1" />
-    <PackageVersion Include="OpenTelemetry.Instrumentation.Runtime" Version="1.8.0" />
+    <PackageVersion Include="OpenTelemetry.Instrumentation.Runtime" Version="1.8.1" />
     <PackageVersion Include="AntDesign" Version="0.15.5" />
     <PackageVersion Include="Ardalis.GuardClauses" Version="4.5.0" />
     <PackageVersion Include="coverlet.collector" Version="6.0.2" />
     <PackageVersion Include="coverlet.msbuild" Version="6.0.2" />
     <PackageVersion Include="EventStore.Client.Grpc.Streams" Version="21.2.0" />
     <PackageVersion Include="FakeItEasy" Version="8.2.0" />
     <PackageVersion Include="FluentAssertions" Version="6.12.0" />
-    <PackageVersion Include="FluentAssertions.Analyzers" Version="0.31.0" />
+    <PackageVersion Include="FluentAssertions.Analyzers" Version="0.32.0" />
     <PackageVersion Include="Microsoft.AspNetCore.Components.WebAssembly" Version="8.0.5" />
     <PackageVersion Include="Microsoft.AspNetCore.Components.WebAssembly.DevServer" Version="8.0.5" />
     <PackageVersion Include="Microsoft.AspNetCore.SignalR.Client" Version="8.0.5" />
     <PackageVersion Include="Microsoft.Extensions.Configuration.Abstractions" Version="8.0.0" />
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
-    <PackageVersion Include="MinVer" Version="4.3.0" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.10.0" />
+    <PackageVersion Include="MinVer" Version="5.0.0" />
     <PackageVersion Include="NetArchTest.Rules" Version="1.3.2" />
     <PackageVersion Include="Newtonsoft.Json" Version="13.0.3" />
     <PackageVersion Include="ReflectionMagic" Version="5.0.1" />
     <PackageVersion Include="Scrutor" Version="4.2.2" />
     <PackageVersion Include="Shouldly" Version="4.2.1" />
-    <PackageVersion Include="Swashbuckle.AspNetCore" Version="6.6.1" />
+    <PackageVersion Include="Swashbuckle.AspNetCore" Version="6.6.2" />
     <PackageVersion Include="TngTech.ArchUnitNET.xUnit" Version="0.10.6" />
     <PackageVersion Include="xunit" Version="2.8.0" />
     <PackageVersion Include="xunit.runner.visualstudio" Version="2.8.0" />

NCafe.sln

@@ -83,7 +83,9 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "NCafe.ServiceDefaults", "sr
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Aspire", "Aspire", "{81ABD551-6547-47EF-8F01-160466F018D2}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Aspire.Hosting.EventStore", "src\Aspire\Aspire.Hosting.EventStore\Aspire.Hosting.EventStore.csproj", "{1F5E7F20-3972-4E73-86A9-83F20F6EE8C7}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Aspire.Hosting.EventStore", "src\Aspire\Aspire.Hosting.EventStore\Aspire.Hosting.EventStore.csproj", "{1F5E7F20-3972-4E73-86A9-83F20F6EE8C7}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NCafe.Cashier.Api.Tests", "src\Cashier\NCafe.Cashier.Api.Tests\NCafe.Cashier.Api.Tests.csproj", "{BFBE126A-F7B7-4DFC-A4AF-962AD53A22C3}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -159,6 +161,10 @@ Global
 		{1F5E7F20-3972-4E73-86A9-83F20F6EE8C7}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{1F5E7F20-3972-4E73-86A9-83F20F6EE8C7}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{1F5E7F20-3972-4E73-86A9-83F20F6EE8C7}.Release|Any CPU.Build.0 = Release|Any CPU
+		{BFBE126A-F7B7-4DFC-A4AF-962AD53A22C3}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{BFBE126A-F7B7-4DFC-A4AF-962AD53A22C3}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{BFBE126A-F7B7-4DFC-A4AF-962AD53A22C3}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{BFBE126A-F7B7-4DFC-A4AF-962AD53A22C3}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -187,6 +193,7 @@ Global
 		{ED16805D-2DEA-4F88-8BCD-E3460AE89CAF} = {81ABD551-6547-47EF-8F01-160466F018D2}
 		{A7B56906-8702-48CD-9CB0-2274802E54B2} = {81ABD551-6547-47EF-8F01-160466F018D2}
 		{1F5E7F20-3972-4E73-86A9-83F20F6EE8C7} = {81ABD551-6547-47EF-8F01-160466F018D2}
+		{BFBE126A-F7B7-4DFC-A4AF-962AD53A22C3} = {A45EA559-97E3-4460-A2E5-F385D0476851}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {F0136BF1-D5F3-4E83-8D23-E3F43534FBB5}

README.md

@@ -76,11 +76,10 @@ All common interfaces and abstractions are here. For example:
 - **AggregateRoot**: Abstract base class for our domain entities
 - **IEvent and Event**: Base for events that represent domain entity state changes
 - **IRepository**: Contract used to fetch and save domain entities
-- **IPublisher**: Contract used for publishing integration events
+- **IBusPublisher**: Contract used for publishing integration events
 - **MessageBus Events**: Integration events used to communicate between microservices
 - **IProjectionService**: Contract used for building projections based on domain entity events
 - **Read Model**: Contract used to fetch and save read models (projections)
-- **Command, Query, Dispatchers and Handlers interfaces**
 - **Basic exceptions**
 
 So, basically, this project is the core of our solution and will only contain the
@@ -114,7 +113,7 @@ abstractions/interfaces (ex.: `IRepository`) instead of implementations
 ### Web API
 
 The entry points (runners) of our microservices. They simply register the required dependencies using methods
-from the Infrastructure project and map endpoints, which use `ICommandDispatcher` or `IQueryDispatcher` (see `Program.cs`).
+from the Infrastructure project and map endpoints, which use `MediatR` to invoke a handler (see `Program.cs`).
 
 These projects have a reference to its Domain, which should actually be called Application, to conform with Clean Architecture
 since it contains use cases. The APIs also have a reference to the Infrastructure project.
@@ -123,8 +122,7 @@ Projection services can also be in the Web API project (Find more about projecti
 
 In case the microservice needs to consume integration events, a Consumer service can be created
 (see `OrdersConsumerService` in `Barista.Api`). Basically, this service implements .NET's `IHostedService`, subscribes
-to a RabbitMQ stream specifying a queue, a topic and a callback, which in case will use `ICommandDispatcher` to, you guessed it,
-dispatch a command to the domain.
+to a RabbitMQ stream specifying a queue, a topic and a callback, which in case will use `MediatR` to invoke a domain command.
 
 ### Web UI
 
@@ -150,7 +148,7 @@ Implementations for all external dependencies are defined in this project. Like:
 - EventStore Repository and Projection Service
 - RabbitMQ publisher
 
-There are some other implementations in here as well, like Command and Query dispatchers, a Logging decorator and
+There are some other implementations in here as well, like a Logging decorator and
 read model repositories (only in-memory for now).
 
 This project also contains methods for registering all the implementations for interfaces defined

src/Admin/NCafe.Admin.Api/NCafe.Admin.Api.csproj

@@ -14,4 +14,11 @@
     <ProjectReference Include="..\NCafe.Admin.Domain\NCafe.Admin.Domain.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <PackageReference Update="MinVer">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+  </ItemGroup>
+
 </Project>

src/Admin/NCafe.Admin.Api/Program.cs

@@ -1,9 +1,8 @@
+using MediatR;
 using NCafe.Admin.Api.Projections;
 using NCafe.Admin.Domain.Commands;
 using NCafe.Admin.Domain.Queries;
 using NCafe.Admin.Domain.ReadModels;
-using NCafe.Core.Commands;
-using NCafe.Core.Queries;
 using NCafe.Infrastructure;
 
 var builder = WebApplication.CreateBuilder(args);
@@ -12,14 +11,12 @@
 
 // Add services to the container.
 builder.Services.AddEventStoreRepository(builder.Configuration)
-                .AddCommandHandlers<CreateProduct>()
-                .AddCommandHandlerLogger()
-                .AddQueryHandlers<CreateProduct>();
-
-builder.Services.AddInMemoryReadModelRepository<Product>()
                 .AddEventStoreProjectionService<Product>()
+                .AddInMemoryReadModelRepository<Product>()
                 .AddHostedService<ProductProjectionService>();
 
+builder.Services.AddMediatR(cfg => cfg.RegisterServicesFromAssemblyContaining<CreateProduct>());
+
 builder.Services.AddEndpointsApiExplorer();
 builder.Services.AddSwaggerGen();
 
@@ -48,16 +45,16 @@
 
 app.UseCors(corsPolicyName);
 
-app.MapGet("/products", async (IQueryDispatcher queryDispatcher) =>
+app.MapGet("/products", async (IMediator mediator) =>
 {
-    var result = await queryDispatcher.QueryAsync(new GetProducts());
+    var result = await mediator.Send(new GetProducts());
     return Results.Ok(result);
 })
 .WithName("GetProducts");
 
-app.MapPost("/products", async (ICommandDispatcher commandDispatcher, CreateProduct command) =>
+app.MapPost("/products", async (IMediator mediator, CreateProduct command) =>
 {
-    await commandDispatcher.DispatchAsync(command);
+    await mediator.Send(command);
     return Results.Created("/products", null);
 })
 .WithName("CreateProduct");

src/Admin/NCafe.Admin.Domain.Tests/Commands/CreateProductTests.cs

@@ -2,6 +2,7 @@
 using NCafe.Admin.Domain.Entities;
 using NCafe.Admin.Domain.Exceptions;
 using NCafe.Core.Repositories;
+using System.Threading;
 
 namespace NCafe.Admin.Domain.Tests.Commands;
 
@@ -26,7 +27,7 @@ public async Task GivenInvalidName_ShouldThrowException(string name)
         var command = new CreateProduct(name, 3);
 
         // Act
-        var exception = await Record.ExceptionAsync(() => _sut.HandleAsync(command));
+        var exception = await Record.ExceptionAsync(() => _sut.Handle(command, CancellationToken.None));
 
         // Assert
         exception.ShouldBeOfType<InvalidProductNameException>();
@@ -41,7 +42,7 @@ public async Task GivenInvalidPrice_ShouldThrowException(decimal price)
         var command = new CreateProduct("Flat White", price);
 
         // Act
-        var exception = await Record.ExceptionAsync(() => _sut.HandleAsync(command));
+        var exception = await Record.ExceptionAsync(() => _sut.Handle(command, CancellationToken.None));
 
         // Assert
         exception.ShouldBeOfType<InvalidProductPriceException>();
@@ -54,10 +55,9 @@ public async Task GivenValidProductInformation_ShouldCreateAndStoreProduct()
         var command = new CreateProduct("Flat White", 3.5m);
 
         // Act
-        var exception = await Record.ExceptionAsync(() => _sut.HandleAsync(command));
+        await _sut.Handle(command, CancellationToken.None);
 
         // Assert
-        exception.ShouldBeNull();
         A.CallTo(() => _repository.Save(A<Product>.That.Matches(p => p.Name == command.Name && p.Price == command.Price)))
             .MustHaveHappenedOnceExactly(); ;
     }

src/Admin/NCafe.Admin.Domain/Commands/CreateProduct.cs

@@ -1,28 +1,17 @@
-using NCafe.Admin.Domain.Entities;
-using NCafe.Admin.Domain.Exceptions;
-using NCafe.Core.Commands;
+using MediatR;
+using NCafe.Admin.Domain.Entities;
 using NCafe.Core.Repositories;
 
 namespace NCafe.Admin.Domain.Commands;
 
-public record CreateProduct(string Name, decimal Price) : ICommand;
+public record CreateProduct(string Name, decimal Price) : IRequest;
 
-internal sealed class CreateProductHandler(IRepository repository) : ICommandHandler<CreateProduct>
+internal sealed class CreateProductHandler(IRepository repository) : IRequestHandler<CreateProduct>
 {
     private readonly IRepository _repository = repository;
 
-    public async Task HandleAsync(CreateProduct command)
+    public async Task Handle(CreateProduct command, CancellationToken cancellationToken)
     {
-        if (string.IsNullOrWhiteSpace(command.Name))
-        {
-            throw new InvalidProductNameException();
-        }
-
-        if (command.Price <= 0)
-        {
-            throw new InvalidProductPriceException(command.Price);
-        }
-
         var product = new Product(Guid.NewGuid(), command.Name, command.Price);
 
         await _repository.Save(product);

src/Admin/NCafe.Admin.Domain/Entities/Product.cs

@@ -1,5 +1,6 @@
 using Ardalis.GuardClauses;
 using NCafe.Admin.Domain.Events;
+using NCafe.Admin.Domain.Exceptions;
 using NCafe.Core.Domain;
 
 namespace NCafe.Admin.Domain.Entities;
@@ -12,9 +13,19 @@ private Product()
 
     public Product(Guid id, string name, decimal price)
     {
-        Id = Guard.Against.Default(id, nameof(id));
-        Name = Guard.Against.NullOrWhiteSpace(name, nameof(name));
-        Price = Guard.Against.NegativeOrZero(price, nameof(price));
+        Id = Guard.Against.Default(id);
+        Name = name;
+        Price = price;
+
+        if (string.IsNullOrWhiteSpace(Name))
+        {
+            throw new InvalidProductNameException();
+        }
+
+        if (Price <= 0)
+        {
+            throw new InvalidProductPriceException(Price);
+        }
 
         RaiseEvent(new ProductCreated(id, name, price));
     }

src/Admin/NCafe.Admin.Domain/NCafe.Admin.Domain.csproj

@@ -6,16 +6,15 @@
 
   <ItemGroup>
     <PackageReference Include="Ardalis.GuardClauses" />
+    <PackageReference Include="MediatR" />
   </ItemGroup>
 
   <ItemGroup>
     <ProjectReference Include="..\..\Common\NCafe.Core\NCafe.Core.csproj" />
   </ItemGroup>
 
   <ItemGroup>
-    <AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleTo">
-      <_Parameter1>$(AssemblyName).Tests</_Parameter1>
-    </AssemblyAttribute>
+    <InternalsVisibleTo Include="$(AssemblyName).Tests" />
   </ItemGroup>
 
 </Project>

src/Admin/NCafe.Admin.Domain/Queries/GetProducts.cs

@@ -1,16 +1,16 @@
-using NCafe.Admin.Domain.ReadModels;
-using NCafe.Core.Queries;
+using MediatR;
+using NCafe.Admin.Domain.ReadModels;
 using NCafe.Core.ReadModels;
 
 namespace NCafe.Admin.Domain.Queries;
 
-public record GetProducts : IQuery<Product[]>;
+public record GetProducts : IRequest<Product[]>;
 
-internal sealed class GetProductsHandler(IReadModelRepository<Product> productRepository) : IQueryHandler<GetProducts, Product[]>
+internal sealed class GetProductsHandler(IReadModelRepository<Product> productRepository) : IRequestHandler<GetProducts, Product[]>
 {
     private readonly IReadModelRepository<Product> _productRepository = productRepository;
 
-    public Task<Product[]> HandleAsync(GetProducts query)
+    public Task<Product[]> Handle(GetProducts query, CancellationToken cancellation)
     {
         var products = _productRepository.GetAll()
             .ToArray();

src/Barista/NCafe.Barista.Api/NCafe.Barista.Api.csproj

@@ -15,4 +15,11 @@
     <ProjectReference Include="..\NCafe.Barista.Domain\NCafe.Barista.Domain.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <PackageReference Update="MinVer">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+  </ItemGroup>
+
 </Project>