（八）ReactAntDesignPro+.Net5WebApi：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