.NET Core中的事务注释属性

Question

我只是好奇，在Java中，@Transactional可以在方法名称上方放置一个属性，并且由于几乎每个应用程序服务方法都使用事务，因此可以简化代码。

// Java example
public class FooApplicationService {
    @Transactional
    public void DoSomething() 
    {
        // do something ...
    }
}

目前，这是在.NET中完成的方式

// .NET example
public class FooApplicationService {
    public void DoSomething() 
    {
        using (var transaction = new TransactionScope())
        {
            // do something ...
            transaction.Complete();
        }
    }
}

是否也可以通过.NET Core中的注释属性来管理事务的？

Answer 1

您可以为此创建动作过滤器

//filter factory is used in order to create new filter instance per request
public class TransactionalAttribute : Attribute, IFilterFactory
{
    //make sure filter marked as not reusable
    public bool IsReusable => false;

    public IFilterMetadata CreateInstance(IServiceProvider serviceProvider)
    {
        return new TransactionalFilter();
    }

    private class TransactionalFilter : IActionFilter
    {
        private TransactionScope _transactionScope;

        public void OnActionExecuting(ActionExecutingContext context)
        {
            _transactionScope = new TransactionScope();
        }

        public void OnActionExecuted(ActionExecutedContext context)
        {
            //if no exception were thrown
            if (context.Exception == null)
                _transactionScope.Complete();
        }
    }
}

像这样使用

public class HomeController : Controller {
    //...    

    [Transactional]
    public IActionResult Test() { /*some code */ }

    //...
}

注意

如@cmart的评论中所述，有一种更优雅的解决方案可以通过使用IAsyncActionFilter

public class TransactionalAttribute : Attribute, IAsyncActionFilter
{
    public async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
    {
        using (var transactionScope = new TransactionScope())
        {
            await next();
            transactionScope.Complete();
        }
    }
}