MSBuild + MSILInect实现编译时AOP之预览

 

   在本文之前的前几篇浅谈.NET编译时注入（C#-->IL）、浅谈VS编译自定义编译任务—MSBuild Task(csproject)、编译时MSIL注入--实践Mono Cecil(1)已经讨论了MSBuild和Mono.Cicel。在这里我们将会利用它来实现一个简单的编译时AOP注入机制（这里所说的编译时是指c#到MSIL的预编译过程）。我更倾向于像EL（微软企业库框架）这类动态AOP。编译时AOP有PostSharp这种被称之为静态AOP框架，其优势在于直接代码语句，性能更好，它不需要我们多余的代码，像EL这种动态AOP，一般我们是不能直接new一个对象，需要容器（Container），在一些你的框架应用种，有时就需要使用者了解，再入我们对于WinForm、WebForm等.net平台上主流的基于微软事件机制的框架，事件方法的截获，往往我们需要改变、包装。在这时静态AOP就显出了他的优势。

Class Diagram：

1：IMethodInject：Interface，拥有Executeing，Exceptioned，ExecuteSuccess三个契约为别为执行前，异常，成功。它们都有公同的参数类型：MethodExecutionEventArgs

Executeing：返回值为bool类型，将决定是否继续执行方法体。Exceptioned：属性Eeption代表发生的异常信息，返回值ExceptionStrategy（取值：Handle, ReThrow, ThrowNew）决定异常处理机制，Handle已处理并忽略，ReThrow重新抛出，ThrowNew抛出一个包装后的来源于MethodExecutionEventArgs 的Exception。ExecuteSuccess，对于拥有返回值的方法，可以修改MethodExecutionEventArgs 的ReturnValue，修改返回值。最后MethodExecutionEventArgs的Order决定多个Attribute的注入先后，即方法截获的先后顺序。

2：MethodInterceptBase：针对于方法Attribute标签，实现方法截获

[AttributeUsage(AttributeTargets.Method, Inherited = false, AllowMultiple = false)]

    public class MethodInterceptBase : Attribute, IMethodInject

    {

        public int Order

        {

            get;

            set;

        }

        #region IMethodInject Members

 

        public virtual bool Executeing(MethodExecutionEventArgs args)

        {

            return true;

        }

 

        public virtual ExceptionStrategy Exceptioned(MethodExecutionEventArgs args)

        {

            return ExceptionStrategy.ReThrow;

        }

 

        public virtual void ExecuteSuccess(MethodExecutionEventArgs args)

        {

 

        }

       

        #endregion

}

2：MatchedMethodInterceptBase：和上面方法之上的MethodInterceptBase大体一致，区别在于其应用于class之上，属性Rule为截获方法匹配（应用于多个方法之上相同截获），支持*匹配。

 

[AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = false)]

    public class MatchedMethodInterceptBase : Attribute, IMethodInject

    {

        public int Order

        {

            get;

            set;

        }

 

        public string Rule

        {

            get;

            set;

        }

 

        #region IMethodInject Members

 

        public virtual bool Executeing(MethodExecutionEventArgs args)

        {

            return true;

        }

 

        public virtual ExceptionStrategy Exceptioned(MethodExecutionEventArgs args)

        {

            return ExceptionStrategy.ReThrow;

        }

 

        public virtual void ExecuteSuccess(MethodExecutionEventArgs args)

        {

 

        }

       

        #endregion

    }

3：PropertyInterceptBase：实现属性的注入，其属性Action（enum PropertyInterceptAction：None Get, Set）指注入属性的get或者Set；

[AttributeUsage(AttributeTargets.Property, Inherited = false, AllowMultiple = false)]

    public class PropertyInterceptBase : Attribute, IMethodInject

    {

        public PropertyInterceptAction Action

        {

            get;

            set;

        }

 

        public int Order

        {

            get;

            set;

        }

        #region IMethodInject Members

 

        public virtual bool Executeing(MethodExecutionEventArgs args)

        {

            return true;

        }

 

        public virtual ExceptionStrategy Exceptioned(MethodExecutionEventArgs args)

        {

            return ExceptionStrategy.ReThrow;

        }

 

        public virtual void ExecuteSuccess(MethodExecutionEventArgs args)

        {

 

        }

 

        #endregion

    }

其上默认都是Executeing继续执行，Exceptioned为抛出不处理，成功不修改result。

下面是一个简单测试Code：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Reflection;

using Green.AOP;

 

namespace Test

{   

    // [TestAOP2Attribute(Rule = "TestMethod1*")]

    public class Class1

    {

        //  [TestAOPPropertyAttribute(Action = PropertyInterceptAction.Set)]

        [TestAOPPropertyGetAttribute(Action = PropertyInterceptAction.Get)]

        public testStrust TestProperty

        {

            get;

            set;

        }

        [Obsolete()]

        public static void Main(string[] args)

        {          

            try

            {

                var y = new Class1();

                // y.TestProperty = DateTime.Now;

                Console.WriteLine(y.TestProperty);

            }

            catch (Exception ex)

            {

                Console.WriteLine(ex.ToString());

            }

            // new Class1().TestMethod1(1, 2, null);

            Console.Read();

            //throw new Exception("exfffffffffffffffffffff");

        }

        //[TestAOPAttribute(Order=1)]

        //[TestAOP1Attribute(TestProperty = 1, Template = "sdsdsd",Order=0)]

        public Class1 TestMethod1(int i, int j, Class1 c)

        {

            Console.WriteLine("ok");

            return new Class1();

        }

    }

    public class TestAOPPropertyGetAttribute : Green.AOP.PropertyInterceptBase

    {

        #region IMethodInject Members

        public override bool Executeing(Green.AOP.MethodExecutionEventArgs args)

        {

            Console.WriteLine("------------------" + args);

            Console.WriteLine(args.Instance);

            Console.WriteLine(args.Method);

            Console.WriteLine(this.GetType() + ":" + "Executeing");

            return true;

        }

        public override Green.AOP.ExceptionStrategy Exceptioned(Green.AOP.MethodExecutionEventArgs args)

        {

            Console.WriteLine(this.GetType() + ":" + "Exceptioned");

            return Green.AOP.ExceptionStrategy.ReThrow;

        }

        public override void ExecuteSuccess(Green.AOP.MethodExecutionEventArgs args)

        {

            Console.WriteLine("-----------");

            Console.WriteLine(this.GetType() + ":" + "ExecuteSuccess" + "--result:" + args.ReturnValue);

        }

        #endregion

    }

    public class TestAOPPropertyAttribute : Green.AOP.PropertyInterceptBase

    {

        #region IMethodInject Members

        public override bool Executeing(Green.AOP.MethodExecutionEventArgs args)

        {

            Console.WriteLine(args.Instance);

            Console.WriteLine(args.Method);

            Console.WriteLine(this.GetType() + ":" + "Executeing");

            return true;

        }

        public override Green.AOP.ExceptionStrategy Exceptioned(Green.AOP.MethodExecutionEventArgs args)

        {

            Console.WriteLine(this.GetType() + ":" + "Exceptioned");

            return Green.AOP.ExceptionStrategy.Handle;

        }

        public override void ExecuteSuccess(Green.AOP.MethodExecutionEventArgs args)

        {

            Console.WriteLine(this.GetType() + ":" + "ExecuteSuccess");

        }

        #endregion

    }

    public class TestAOP2Attribute : Green.AOP.MatchedMethodInterceptBase

    {

        #region IMethodInject Members

        public override bool Executeing(Green.AOP.MethodExecutionEventArgs args)

        {

            Console.WriteLine(args.Instance);

            Console.WriteLine(args.Method);

            Console.WriteLine(this.GetType() + ":" + "Executeing");

            return true;

        }

        public override Green.AOP.ExceptionStrategy Exceptioned(Green.AOP.MethodExecutionEventArgs args)

        {

            Console.WriteLine(this.GetType() + ":" + "Exceptioned");

            return Green.AOP.ExceptionStrategy.Handle;

        }

        public override void ExecuteSuccess(Green.AOP.MethodExecutionEventArgs args)

        {

            Console.WriteLine(this.GetType() + ":" + "ExecuteSuccess");

        }

        #endregion

        #region IMethodInject Members

        public bool Match(System.Reflection.MethodBase method)

        {

            return true;

        }

        #endregion

    }

 

    //[AttributeUsage(AttributeTargets.Method)]

    public class TestAOPAttribute : Green.AOP.MethodInterceptBase

    {

        #region IMethodInject Members

        public override bool Executeing(Green.AOP.MethodExecutionEventArgs args)

        {

            Console.WriteLine(this.GetType() + ":" + "Executeing");

            return true;

        }

 

        public override Green.AOP.ExceptionStrategy Exceptioned(Green.AOP.MethodExecutionEventArgs args)

        {

            Console.WriteLine(this.GetType() + ":" + "Exceptioned");

            return Green.AOP.ExceptionStrategy.Handle;

        }

 

        public override void ExecuteSuccess(Green.AOP.MethodExecutionEventArgs args)

        {

            Console.WriteLine(this.GetType() + ":" + "ExecuteSuccess");

        }

 

        #endregion

 

        #region IMethodInject Members

 

 

        public bool Match(System.Reflection.MethodBase method)

        {

            return true;

        }

 

        #endregion

    }

 

    [AttributeUsage(AttributeTargets.Method)]

    public class TestAOP1Attribute : Attribute, Green.AOP.IMethodInject

    {

        public int Order

        {

            get;

            set;

        }

 

        public int TestProperty

        {

            get;

            set;

        }

 

        public string Template

        {

            get;

            set;

        }

 

        #region IMethodInject Members

 

        public bool Executeing(Green.AOP.MethodExecutionEventArgs args)

        {

            Console.WriteLine(this.GetType() + ":" + "Executeing");

            return true;

        }

 

        public Green.AOP.ExceptionStrategy Exceptioned(Green.AOP.MethodExecutionEventArgs args)

        {

            Console.WriteLine(this.GetType() + ":" + "Exceptioned");

            return Green.AOP.ExceptionStrategy.Handle;

        }

 

        public void ExecuteSuccess(Green.AOP.MethodExecutionEventArgs args)

        {

            Console.WriteLine(this.GetType() + ":" + "ExecuteSuccess");

        }

 

        #endregion

 

        #region IMethodInject Members

 

 

        public bool Match(System.Reflection.MethodBase method)

        {

            return true;

        }

 

        #endregion

    }

 

}

注意测试有两种方式（由于没有安装包）：

1：先重编译测试项目，运行ConsoleApplication2（在属性中修改控制台其实参数）。在查看测试项目。

2：将项目ConsoleApplication2修改为类库，在添加修改csprojec信息，Task位于Green.AOP.MyBuildTask，具体可以参见上一篇浅谈VS编译自定义编译任务—MSBuild Task(csproject)。

在后续将会从简单Demo分析实现原理。