C# 面向切面编程之AspectCore初探

写在前面

AspectCore 是Lemon名下的一个国产Aop框架，提供了一个全新的轻量级和模块化的Aop解决方案。面向切面也可以叫做代码拦截，分为静态和动态两种模式，AspectCore 可以实现动态代理，支持程序运行时在内存中“临时”生成 AOP 动态代理类。

老规矩从 Nuget 安装 AspectCore.Extensions.DependencyInjection 包。

代码实现

using AspectCore.DynamicProxy;public class Program
{public static void Main(string[] args){Console.WriteLine("Start...");ProxyGeneratorBuilder proxyGeneratorBuilder = new ProxyGeneratorBuilder();using (IProxyGenerator proxyGenerator = proxyGeneratorBuilder.Build()){Person p = proxyGenerator.CreateClassProxy<Person>();Console.WriteLine(p.GetType().BaseType);p.Say($"{Environment.NewLine} Hello World!");}Console.WriteLine("End");Console.ReadLine();}
}public class CustomInterceptor : AbstractInterceptorAttribute
{public async override Task Invoke(AspectContext context, AspectDelegate next){try{Console.WriteLine("Before service call");await next(context);}catch (Exception){Console.WriteLine("Service threw an exception!");throw;}finally{Console.WriteLine("After service call");}}
}public class Person
{[CustomInterceptor]public virtual void Say(string msg){Console.WriteLine("service calling..." + msg);}
}

调用示例

如图，代理类将Say方法包裹了起来。

如果修改一下CustomInterceptor 的Invoke方法，可以直接根据条件控制代码的分支跳转。

public class CustomInterceptor : AbstractInterceptorAttribute
{public async override Task Invoke(AspectContext context, AspectDelegate next){try{Console.WriteLine("Before service call");if (false)await next(context);elseawait Task.Delay(1000);}catch (Exception){Console.WriteLine("Service threw an exception!");throw;}finally{Console.WriteLine("After service call");}}
}

运行代码 Person中的Say方法本体就被跳过了：