命令模式和消息幂等去重

src/HelloShop.OrderingService/Commands/IdentifiedCommand.cs

@@ -0,0 +1,14 @@
+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+using MediatR;
+
+namespace HelloShop.OrderingService.Commands
+{
+    public class IdentifiedCommand<TRequest, TResponse>(TRequest command, Guid id) : IRequest<TResponse> where TRequest : IRequest<TResponse>
+    {
+        public TRequest Command { get; } = command;
+
+        public Guid Id { get; } = id;
+    }
+}

src/HelloShop.OrderingService/Commands/IdentifiedCommandHandler.cs

@@ -0,0 +1,25 @@
+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+using HelloShop.OrderingService.Services;
+using MediatR;
+
+namespace HelloShop.OrderingService.Commands
+{
+    public abstract class IdentifiedCommandHandler<TRequest, TResponse>(IMediator mediator, IClientRequestManager requestManager) : IRequestHandler<IdentifiedCommand<TRequest, TResponse>, TResponse> where TRequest : IRequest<TResponse>
+    {
+        protected virtual TResponse? CreateResultForDuplicateRequest() => default;
+
+        public async Task<TResponse> Handle(IdentifiedCommand<TRequest, TResponse> request, CancellationToken cancellationToken)
+        {
+            if (await requestManager.ExistAsync(request.Id))
+            {
+                return CreateResultForDuplicateRequest() ?? throw new NotImplementedException();
+            }
+
+            await requestManager.CreateRequestForCommandAsync<TRequest>(request.Id);
+
+            return await mediator.Send(request.Command, cancellationToken);
+        }
+    }
+}

src/HelloShop.OrderingService/Commands/Orders/CreateOrderCommand.cs

@@ -0,0 +1,61 @@
+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+using MediatR;
+
+namespace HelloShop.OrderingService.Commands.Orders
+{
+    public class CreateOrderCommand : IRequest<bool>
+    {
+        public int UserId { get; set; }
+
+        public required string UserName { get; set; }
+
+        #region Order Items
+
+        public required IEnumerable<CreateOrderCommandItem> OrderItems { get; set; }
+
+        #endregion
+
+        #region PaymentMethod
+
+        public required string CardAlias { get; set; }
+
+        public required string CardNumber { get; set; }
+
+        public required string CardHolderName { get; set; }
+
+        public string? CardSecurityNumber { get; set; }
+
+        public DateTimeOffset? CardExpiration { get; set; }
+
+        #endregion
+
+        #region Address
+
+        public required string Country { get; set; }
+
+        public required string State { get; set; }
+
+        public required string City { get; set; }
+
+        public required string Street { get; set; }
+
+        public required string ZipCode { get; set; }
+
+        #endregion
+
+        public class CreateOrderCommandItem
+        {
+            public int ProductId { get; set; }
+
+            public required string ProductName { get; set; }
+
+            public required string PictureUrl { get; set; }
+
+            public decimal UnitPrice { get; set; }
+
+            public int Units { get; set; }
+        }
+    }
+}

src/HelloShop.OrderingService/Commands/Orders/CreateOrderCommandHandler.cs

@@ -0,0 +1,21 @@
+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+using HelloShop.OrderingService.Services;
+using MediatR;
+
+namespace HelloShop.OrderingService.Commands.Orders
+{
+    public class CreateOrderCommandHandler : IRequestHandler<CreateOrderCommand, bool>
+    {
+        public Task<bool> Handle(CreateOrderCommand request, CancellationToken cancellationToken)
+        {
+            throw new NotImplementedException();
+        }
+    }
+
+    public class CreateOrderIdentifiedCommandHandler(IMediator mediator, IClientRequestManager requestManager) : IdentifiedCommandHandler<CreateOrderCommand, bool>(mediator, requestManager)
+    {
+        protected override bool CreateResultForDuplicateRequest() => default;
+    }
+}

src/HelloShop.OrderingService/Entities/Idempotency/ClientRequest.cs

@@ -0,0 +1,14 @@
+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+namespace HelloShop.OrderingService.Entities.Idempotency
+{
+    public class ClientRequest
+    {
+        public Guid Id { get; set; }
+
+        public required string Name { get; set; }
+
+        public DateTimeOffset Time { get; set; }
+    }
+}

src/HelloShop.OrderingService/Extensions/Extensions.cs

@@ -3,8 +3,10 @@
 
 using HelloShop.OrderingService.Constants;
 using HelloShop.OrderingService.Infrastructure;
+using HelloShop.OrderingService.Services;
 using HelloShop.ServiceDefaults.Extensions;
 using Microsoft.EntityFrameworkCore;
+using System.Reflection;
 
 namespace HelloShop.OrderingService.Extensions
 {
@@ -18,6 +20,13 @@ namespace HelloShop.OrderingService.Extensions
             {
                 options.UseNpgsql(builder.Configuration.GetConnectionString(DbConstants.MasterConnectionStringName));
             });
+
+            builder.Services.AddScoped<IClientRequestManager, ClientRequestManager>();
+
+            builder.Services.AddMediatR(options =>
+            {
+                options.RegisterServicesFromAssembly(Assembly.GetExecutingAssembly());
+            });
         }
 
         public static WebApplication MapApplicationEndpoints(this WebApplication app)

src/HelloShop.OrderingService/HelloShop.OrderingService.csproj

@@ -8,6 +8,7 @@
     <ProjectReference Include="..\HelloShop.ServiceDefaults\HelloShop.ServiceDefaults.csproj" />
   </ItemGroup>
   <ItemGroup>
+    <PackageReference Include="MediatR" Version="12.4.0" />
     <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="8.0.8" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="8.0.8">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

src/HelloShop.OrderingService/Infrastructure/EntityConfigurations/Idempotency/ClientRequestEntityTypeConfiguration.cs

@@ -0,0 +1,21 @@
+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+using HelloShop.OrderingService.Entities.Idempotency;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+
+namespace HelloShop.OrderingService.Infrastructure.EntityConfigurations.Idempotency
+{
+    public class ClientRequestEntityTypeConfiguration : IEntityTypeConfiguration<ClientRequest>
+    {
+        public void Configure(EntityTypeBuilder<ClientRequest> builder)
+        {
+            builder.ToTable("ClientRequests");
+
+            builder.HasKey(t => t.Id);
+
+            builder.Property(t => t.Name).HasMaxLength(64);
+        }
+    }
+}

src/HelloShop.OrderingService/Services/ClientRequestManager.cs

@@ -0,0 +1,30 @@
+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+using HelloShop.OrderingService.Entities.Idempotency;
+using HelloShop.OrderingService.Infrastructure;
+
+namespace HelloShop.OrderingService.Services
+{
+    public class ClientRequestManager(OrderingServiceDbContext dbContext) : IClientRequestManager
+    {
+        public async Task<bool> ExistAsync(Guid id) => await dbContext.FindAsync<ClientRequest>(id) is not null;
+
+        public async Task CreateRequestForCommandAsync<T>(Guid id)
+        {
+            if (await ExistAsync(id))
+            {
+                throw new Exception($"Request with {id} already exists");
+            }
+
+            await dbContext.AddAsync(new ClientRequest
+            {
+                Id = id,
+                Name = typeof(T).Name,
+                Time = DateTime.UtcNow
+            });
+
+            await dbContext.SaveChangesAsync();
+        }
+    }
+}

src/HelloShop.OrderingService/Services/IClientRequestManager.cs

@@ -0,0 +1,12 @@
+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+namespace HelloShop.OrderingService.Services
+{
+    public interface IClientRequestManager
+    {
+        Task<bool> ExistAsync(Guid id);
+
+        Task CreateRequestForCommandAsync<T>(Guid id);
+    }
+}