（八）React Ant Design Pro + .Net5 WebApi：后端环境搭建-Aop

一、Aop

Aop 面向切面编程(Aspect Oriented Program），在项目中，很多地方都会用到Aop的概念，比如：过滤器(Filter)，中间件(Middleware) 通常用来处理数据请求、切面缓存、记录日志、异常捕获等等。但是想在服务层中使用Aop，前面说的就不好使了，目的是减少代码入侵，降低解耦，又能实现业务需求，才是Aop意义所在。前面介绍使用了Autofac，在这还能发挥作用。

1、安装

安装Autofac.Extras.DynamicProxy，Autofac实现Aop用的是Castle.Core动态代理，Castle.Core可以单独使用，跟Autofac配合起来更方便。Autofac.Extras.DynamicProxy依赖Autofac，所以有的文章是直接就装了这个包，一个效果。

2、异步处理

Castle.Core本身是不支持异步的，所以参考封装异步Aop类 AsyncInterceptorBase 继承 IInterceptor。

public abstract class AsyncInterceptorBase : IInterceptor

{

    public AsyncInterceptorBase()

    {

    }

    public void Intercept(IInvocation invocation)

    {

        BeforeProceed(invocation);

        invocation.Proceed();

        if (IsAsyncMethod(invocation.MethodInvocationTarget))

        {

            InterceptAsync((dynamic)invocation.ReturnValue, invocation);

        }

        else

        {

            AfterProceedSync(invocation);

        }

    }

    private bool CheckMethodReturnTypeIsTaskType(MethodInfo method)

    {

        var methodReturnType = method.ReturnType;

        if (methodReturnType.IsGenericType)

        {

            if (methodReturnType.GetGenericTypeDefinition() == typeof(Task<>) ||

                methodReturnType.GetGenericTypeDefinition() == typeof(ValueTask<>))

                return true;

        }

        else

        {

            if (methodReturnType == typeof(Task) ||

                methodReturnType == typeof(ValueTask))

                return true;

        }

        return false;

    }

    private bool IsAsyncMethod(MethodInfo method)

    {

        bool isDefAsync = Attribute.IsDefined(method, typeof(AsyncStateMachineAttribute), false);

        bool isTaskType = CheckMethodReturnTypeIsTaskType(method);

        bool isAsync = isDefAsync && isTaskType;

        return isAsync;

    }

    private async Task InterceptAsync(Task task, IInvocation invocation)

    {

        await task.ConfigureAwait(false);

        AfterProceedAsync(invocation, false);

    }

    private async Task<TResult> InterceptAsync<TResult>(Task<TResult> task, IInvocation invocation)

    {

        TResult ProceedAsyncResult = await task.ConfigureAwait(false);

        invocation.ReturnValue = ProceedAsyncResult;

        AfterProceedAsync(invocation, true);

        return ProceedAsyncResult;

    }

    private async ValueTask InterceptAsync(ValueTask task, IInvocation invocation)

    {

        await task.ConfigureAwait(false);

        AfterProceedAsync(invocation, false);

    }

    private async ValueTask<TResult> InterceptAsync<TResult>(ValueTask<TResult> task, IInvocation invocation)

    {

        TResult ProceedAsyncResult = await task.ConfigureAwait(false);

        invocation.ReturnValue = ProceedAsyncResult;

        AfterProceedAsync(invocation, true);

        return ProceedAsyncResult;

    }

    protected virtual void BeforeProceed(IInvocation invocation) { }

    protected virtual void AfterProceedSync(IInvocation invocation) { }

    protected virtual void AfterProceedAsync(IInvocation invocation, bool hasAsynResult) { }

}

新建一个服务切面类 ServiceAop 继承 AsyncInterceptorBase

public class ServiceAop : AsyncInterceptorBase

{

    private readonly ILogger<ServiceAop> _logger;

    public ServiceAop(ILogger<ServiceAop> logger) {

        _logger = logger;

    }

    protected override void BeforeProceed(IInvocation invocation)

    {

        _logger.LogInformation($"ServiceAop调用方法：{invocation.Method.Name}，参数：{JsonConvert.SerializeObject(invocation.Arguments) }");

    }

    protected override void AfterProceedSync(IInvocation invocation)

    {

        _logger.LogInformation($"ServiceAop同步返回结果：{JsonConvert.SerializeObject(invocation.ReturnValue)}");

    }

    protected override void AfterProceedAsync(IInvocation invocation, bool hasAsynResult)

    {

        _logger.LogInformation($"ServiceAop异步返回结果：{JsonConvert.SerializeObject(invocation.ReturnValue)}");

    }

}

两个类放在了新建的Aop文件夹里，通过Autofac注入进行使用，修改 Startup.cs 代码如图：（不太明白的请看：（五）Autofac）

3、使用效果

二、前人栽树，后人乘凉

https://blog.csdn.net/q932104843/article/details/97611912

https://www.cnblogs.com/wswind/p/13863104.html

巴特西