AbpVnext 本地事件总线

补充知识

发布订阅

概念

应用场景

本地事件总线允许服务发布和订阅进程内事件，这意味着如果两个服务>(发布者和订阅者)在同一个进程中运行，那么它是合适的

完整示例
DDD开发规范: 先定义好接口层、后实现层、暴露接口

对于要更新的实体

//领域层的实体
public class Book : FullAuditedEntity<Guid>, IHasExtraProperties, IMultiTenant
{
   public string Name{get;set;}

   public string Author {get;set;}

   public long Price {get;set}
   
   public string Title {get;set;}

   public string Classify{get;set;}

   //条形码
   public string BarCode {get;set;}
   // 出版商
   public string Issue{get;set;}
   // 页数
   public string PageTotal{get;set;}
  
   public string BuyerId{get;set;}

   public DateTime? ModifyTime{get;set}
}

//这个实体是必须有的
public class BookRecordEto{

    public string Name{get;set;}

    public string Author {get;set;}

    public long Price {get;set}

    public DateTime? ModifyTime{get;set}
}

//发布事件
public class BookService: ITransientDependency
{
    //Abp使用了字典来保存对实例的引用
    public IAbpLazyServiceProvider LazyServiceProvider { get; set; }

    //按需注入
    protected ILocalEventBus  LocalEventBus => LazyServiceProvider.LazyGetRequiredService<ILocalEventBus >(); 

    //仓储--对应Book的数据库表
    protected IBookRepository BookRepository => LazyGetRequiredService<IBookRepository>();

    public async Task UpdateData(Guid id)
    {
        var book =  await BookRepository.FindAsync(x=>x.Id = id);
        if (book == null){//不存在实体}
        var updateEntity = await BookRepository.UpdateAsync(book);
        if (updateEntity == null){//更新失败}
        
        //实体数据发生变更，发布事件
        await LocalEventBus.PublishAsync(new BookEto(){
            Name = book.Name;
            Author = book.Author;
            Price = book.Price;
            ModifyTime = DateTime.Now;
        });
    } 
}

//订阅事件
using Volo.Abp.DependencyInjection;
using Volo.Abp.EventBus;
public class EventBusHandler: ApplicationService,
      , ILocalEventHandler<BookRecordEto> 
      , ITransientDependency
{
    // 进行业务数据更新，比如要更新购买这边书读者记录
    public IAbpLazyServiceProvider LazyServiceProvider{get;set;}
 
    protected IBookBoughtRecordRepository BoughtRecordRepository => LazyServiceProvider.LazyGetRequiredService<IBookBoughtRecordRepository>();

    [UnitOfWork]//这个特性以及方法头里面的virtual很重要
    public async virtual Task HandleEventAsync(BookRecordEto eventData)
    {
        //获取购买记录
        var record =  await  BoughtRecordRepository.GetQueryableAsync();

        var recordList = await AsyncExecuter.ToListAsync(record);
        
        if(recordList.Count() != 0){

            var boughtRecord  = ObjectMapper.Map(eventData, new BoughtRecord());
            //插入一条数据
            await BoughtRecordRepository.InsertAsync(boughtRecord);
        }
    }
}

总结

标签：set,string,get,AbpVnext,await,总线,book,public,分布式
来源： https://www.cnblogs.com/Tamper/p/16481846.html