（三）毛子整洁架构（Infrastructure层/DapperHelper/乐观锁）

---

---

项目地址

• 教程作者：
• 教程地址：

• 代码仓库地址：

• 所用到的框架和插件：

dbt 
airflow

一、Infrastructure Layer

添加对Application层和Domain层的引用

1.1 创建Application层需要的服务

1. Clock服务

• 当前时间接口的实现

using Bookify.Application.Abstractions.Clock;
namespace Bookify.Infrastructure.Clock;
internal sealed class DateTimeProvider : IDateTimeProvider
{public DateTime UtcNow => DateTime.UtcNow;
}

2. Email 服务

• Email的服务，实现Appliaction的接口

using Bookify.Application.Abstractions.Email;
namespace Bookify.Infrastructure.Email;
internal sealed class EmailService : IEmailService
{public Task SendAsync(Domain.Users.Email recipient, string subject, string body){return Task.CompletedTask;}
}

3. 注册服务

• 注册上面的两个服务

public static class DependencyInjection
{public static IServiceCollection AddInfrastructure(this IServiceCollection services,IConfiguration configuration){services.AddTransient<IDateTimeProvider, DateTimeProvider>();services.AddTransient<IEmailService, EmailService>();return services;}
}

1.2 数据库服务

1. 表配置Configurations

1. BookingConfiguration.cs

internal sealed class BookingConfiguration : IEntityTypeConfiguration<Booking>
{public void Configure(EntityTypeBuilder<Booking> builder){//设置数据库表名为 bookingsbuilder.ToTable("bookings");//设置主键为 Idbuilder.HasKey(booking => booking.Id);//OwnsOne处理值对象builder.OwnsOne(booking => booking.PriceForPeriod, priceBuilder =>{priceBuilder.Property(money => money.Currency).HasConversion(currency => currency.Code, code => Currency.FromCode(code));});builder.OwnsOne(booking => booking.CleaningFee, priceBuilder =>{priceBuilder.Property(money => money.Currency).HasConversion(currency => currency.Code, code => Currency.FromCode(code));});builder.OwnsOne(booking => booking.AmenitiesUpCharge, priceBuilder =>{priceBuilder.Property(money => money.Currency).HasConversion(currency => currency.Code, code => Currency.FromCode(code));});builder.OwnsOne(booking => booking.TotalPrice, priceBuilder =>{priceBuilder.Property(money => money.Currency).HasConversion(currency => currency.Code, code => Currency.FromCode(code));});builder.OwnsOne(booking => booking.Duration);builder.HasOne<Apartment>().WithMany().HasForeignKey(booking => booking.ApartmentId);builder.HasOne<User>().WithMany().HasForeignKey(booking => booking.UserId);}
}

2. ApartmentConfiguration.cs

internal sealed class ApartmentConfiguration : IEntityTypeConfiguration<Apartment>
{public void Configure(EntityTypeBuilder<Apartment> builder){builder.ToTable("apartments");builder.HasKey(apartment => apartment.Id);builder.OwnsOne(apartment => apartment.Address);builder.Property(apartment => apartment.Name).HasMaxLength(200).HasConversion(name => name.Value, value => new Name(value));builder.Property(apartment => apartment.Description).HasMaxLength(2000).HasConversion(description => description.Value, value => new Description(value));builder.OwnsOne(apartment => apartment.Price, priceBuilder =>{priceBuilder.Property(money => money.Currency).HasConversion(currency => currency.Code, code => Currency.FromCode(code));});builder.OwnsOne(apartment => apartment.CleaningFee, priceBuilder =>{priceBuilder.Property(money => money.Currency).HasConversion(currency => currency.Code, code => Currency.FromCode(code));});builder.Property<uint>("Version").IsRowVersion();}
}

2. Respository实现

1. Repository.cs

internal abstract class Repository<T>where T : Entity
{protected readonly ApplicationDbContext DbContext;protected Repository(ApplicationDbContext dbContext){DbContext = dbContext;}public async Task<T?> GetByIdAsync(Guid id,CancellationToken cancellationToken = default){return await DbContext.Set<T>().FirstOrDefaultAsync(user => user.Id == id, cancellationToken);}public void Add(T entity){DbContext.Add(entity);}
}

2. BookingRepository.cs

namespace Bookify.Infrastructure.Repositories;internal sealed class BookingRepository : Repository<Booking>, IBookingRepository
{private static readonly BookingStatus[] ActiveBookingStatuses ={BookingStatus.Reserved,BookingStatus.Confirmed,BookingStatus.Completed};public BookingRepository(ApplicationDbContext dbContext): base(dbContext){}public async Task<bool> IsOverlappingAsync(Apartment apartment,DateRange duration,CancellationToken cancellationToken = default){return await DbContext.Set<Booking>().AnyAsync(booking =>booking.ApartmentId == apartment.Id &&booking.Duration.Start <= duration.End &&booking.Duration.End >= duration.Start &&ActiveBookingStatuses.Contains(booking.Status),cancellationToken);}
}

3. 数据库链接Factory实现

//创建Dapper链接数据库的工厂
internal sealed class SqlConnectionFactory : ISqlConnectionFactory
{private readonly string _connectionString;public SqlConnectionFactory(string connectionString){_connectionString = connectionString;}public IDbConnection CreateConnection(){var connection = new NpgsqlConnection(_connectionString);connection.Open();return connection;}
}

4. Dapper的DataOnly服务实现

namespace Bookify.Infrastructure.Data;
/// <summary>
/// A Dapper type handler for <see cref="DateOnly"/>.
/// </summary>
internal sealed class DateOnlyTypeHandler : SqlMapper.TypeHandler<DateOnly>
{public override DateOnly Parse(object value) => DateOnly.FromDateTime((DateTime)value);public override void SetValue(IDbDataParameter parameter, DateOnly value){parameter.DbType = DbType.Date;parameter.Value = value;}
}

5. 所有数据库服务注册

• 注册所有infrastructure的服务

public static class DependencyInjection
{public static IServiceCollection AddInfrastructure(this IServiceCollection services,IConfiguration configuration){services.AddTransient<IDateTimeProvider, DateTimeProvider>();services.AddTransient<IEmailService, EmailService>();string connectionString =configuration.GetConnectionString("Database") ??throw new ArgumentNullException(nameof(configuration));services.AddDbContext<ApplicationDbContext>(options =>{options.UseNpgsql(connectionString).UseSnakeCaseNamingConvention();});services.AddScoped<IUserRepository, UserRepository>();services.AddScoped<IApartmentRepository, ApartmentRepository>();services.AddScoped<IBookingRepository, BookingRepository>();services.AddScoped<IUnitOfWork>(sp => sp.GetRequiredService<ApplicationDbContext>());services.AddSingleton<ISqlConnectionFactory>(_ =>new SqlConnectionFactory(connectionString));SqlMapper.AddTypeHandler(new DateOnlyTypeHandler());return services;}
}

1.3 基于RowVersion的乐观锁

1. 添加RowVersion字段

• 这里我们预定apartment需要乐观锁，所以在他的数据库configuration里添加

2. 修改ReserveBookingCommandHandler

• 发成冲突后，返回已经预定的错误