DDD 需要引用的程序集

例如 订单服务 涉及到并发 业务复杂 所以使用领域驱动涉及到

集成事件总线 基于 rabbitmq 异步发布用于与其他服务通信 （订阅发布模式）

领域事件 基于 MediatR 涉及到  一对一 (IRequest<bool>,IRequestHandler<AddUserCommand, bool>) ，一对多(INotification,INotificationHandler<RegistorSendMailEvent>)

Dapper 用于查询 

Grpc 用于服务与服务之间的通信

健康检查

身份验证 jwt 或者 identityserver4 

身份授权

先来Program 配置

对前台 返回实体 帕斯卡命名

引用 NewtonsoftJson 实现

    <PackageReference Include="Microsoft.AspNetCore.Mvc.NewtonsoftJson" Version="8.0.4" />

builder.Services.AddControllers(options =>
{
    //全局异常过滤器
    options.Filters.Add<GolbalExceptionFilter>();
}).AddNewtonsoftJson(options =>
{
    options.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();
});

　

健康检查

可以检查 mysql 健康状态 可以使用UI查看健康检查

引用 AspNetCore.HealthChecks.UI

<PackageReference Include="AspNetCore.HealthChecks.UI" Version="8.0.1" />
<PackageReference Include="AspNetCore.HealthChecks.UI.Client" Version="8.0.1" />
<PackageReference Include="AspNetCore.HealthChecks.UI.InMemory.Storage" Version="8.0.1" />

builder.Services.AddHealthChecks().AddCheck("self", check => HealthCheckResult.Healthy(), tags: new string[] { "self" });

　

app.UseHealthChecks("/healthz", new Microsoft.AspNetCore.Diagnostics.HealthChecks.HealthCheckOptions
{
    Predicate = _ => true,
    ResponseWriter = UIResponseWriter.WriteHealthCheckUIResponse
});

app.UseHealthChecks("/health_self", new Microsoft.AspNetCore.Diagnostics.HealthChecks.HealthCheckOptions
{
    Predicate = result => result.Name.Contains("self")
});
//增加 HealthChecksUI 中间件
app.UseHealthChecksUI(setup: options =>
{
    //UI 访问路径
    options.UIPath = "/health-ui";
});

　HealthChecksUI appsettings.json 配置

  "HealthChecksUI": {
    "HealthChecks": [
      {
        "Name": "Test Health",
        "Uri": "/healthz"
      }
    ],
    "EvaluationTimeinSeconds": 10,
    "MinimumSecondsBetweenFailureNotifications": 30
  }

　　

mysql 开启失败重试 

//添加事件总线日志数据库配置
builder.Services.AddDbContext<IntegrationEventLogContext>(options =>
{
    // 内存数据库
    // options.UseInMemoryDatabase("test");
    //mysql 数据库
    string mysqlStr = builder.Configuration.GetConnectionString("mysql") ?? throw new UserDomainException("mysql连接字符串为null");
    options.UseMySql(mysqlStr, new MySqlServerVersion(new Version(8, 0, 27)), dbOptions =>
    {
        //数据迁移
        dbOptions.MigrationsAssembly(Assembly.GetExecutingAssembly().GetName().Name);
        //开启失败重试
        dbOptions.EnableRetryOnFailure(maxRetryCount: 15, TimeSpan.FromSeconds(15), null);
    });
});

　　

  "ConnectionStrings": {
    "redis": "192.168.0.168:6379",
    "mysql": "server=192.168.0.168;port=3306;database=UserDDD;pwd=123456;uid=root;"
  },

一定要注意事务 需要用到事务的时候  需要编写执行策略否测失败重试会报错

  public async Task ExecuteAsync(Func<Task> action)
  {
      var strategy = _context.Database.CreateExecutionStrategy();
      await strategy.ExecuteAsync(async () =>
      {
          await using var transaction = await _context.Database.BeginTransactionAsync();
          await action();
          await transaction.CommitAsync();
      });
  }

　　

MediatR

  <PackageReference Include="MediatR" Version="12.2.0" />

builder.Services.AddMediatR(config =>
{
    config.RegisterServicesFromAssemblies(typeof(Program).Assembly);
});

　　

AutoMapper
 <PackageReference Include="AutoMapper" Version="13.0.1" />

builder.Services.AddAutoMapper(options =>
{
    //程序集注册
    options.AddMaps(Assembly.GetExecutingAssembly());
});

　

使用 AutoMapper 时

1. 会扫描程序集的Profiles 名称的文件夹 
2. 对象有子对象时 应先映射子对象
3. 映射类需要继承 Profile

    public class AccountProfile : Profile
    {
        public AccountProfile()
        {
            //子对象先映射
            CreateMap<BillInputCreate, Bill>().ReverseMap();
            //子对象先映射
            CreateMap<BillViewModel, Bill>().ReverseMap();
            CreateMap<AccountViewModel, Account>() .ForMember(x => x.Bills, p => p.MapFrom(y => y.Bills)).ReverseMap();
            CreateMap<AccountInputCreate, Account>().ForMember(x => x.Bills, p => p.MapFrom(y => y.billInputCreates)).ReverseMap();
            
        }
    }