MSBuild + MSILInect實現編譯時AOP之預覽

      在本文之前的前幾篇淺談.NET編譯時注入（C#-->IL）、淺談VS編譯自定義編譯任務—MSBuild Task(csproject)、編譯時MSIL注入--實踐Mono Cecil(1)已經討論了MSBuild和Mono.Cicel。在這裡我們將會利用它來實現一個簡單的編譯時AOP注入機制（這裡所說的編譯時是指c#到MSIL的預編譯過程）。我更傾向於像EL（微軟企業庫框架）這類動態AOP。編譯時AOP有PostSharp這種被稱之為靜態AOP框架，其優勢在於直接程式碼語句，效能更好，它不需要我們多餘的程式碼，像EL這種動態AOP，一般我們是不能直接new一個物件，需要容器（Container），在一些你的框架應用種，有時就需要使用者瞭解，再入我們對於WinForm、WebForm等.net平臺上主流的基於微軟事件機制的框架，事件方法的截獲，往往我們需要改變、包裝。在這時靜態AOP就顯出了他的優勢。

Class Diagram：

1：IMethodInject：Interface，擁有Executeing，Exceptioned，ExecuteSuccess三個契約為別為執行前，異常，成功。它們都有公同的引數型別：MethodExecutionEventArgs

 

    Executeing：返回值為bool型別，將決定是否繼續執行方法體。Exceptioned：屬性Eeption代表發生的異常資訊，返回值ExceptionStrategy（取值：Handle, ReThrow, ThrowNew）決定異常處理機制，Handle已處理並忽略，ReThrow重新丟擲，ThrowNew丟擲一個包裝後的來源於MethodExecutionEventArgs 的Exception。ExecuteSuccess，對於擁有返回值的方法，可以修改MethodExecutionEventArgs 的ReturnValue，修改返回值。最後MethodExecutionEventArgs的Order決定多個Attribute的注入先後，即方法截獲的先後順序。

1：MethodInterceptBase：針對於方法Attribute標籤，實現方法截獲

[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大體一致，區別在於其應用於class之上，屬性Rule為截獲方法匹配（應用於多個方法之上相同截獲），支援*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：實現屬性的注入，其屬性Action（enum PropertyInterceptAction：None Get, Set）指注入屬性的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
    }

其上預設都是Executeing繼續執行，Exceptioned為丟擲不處理，成功不修改result。

下面是一個簡單測試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

    }

 

}

 注意測試有兩種方式（由於沒有安裝包）：

1：先重編譯測試專案，執行ConsoleApplication2（在屬性中修改控制檯其實引數）。在檢視測試專案。

2：將專案ConsoleApplication2修改為類庫，在新增修改csprojec資訊，Task位於Green.AOP.MyBuildTask，具體可以參見上一篇淺談VS編譯自定義編譯任務—MSBuild Task(csproject)。

在後續將會從簡單Demo分析實現原理。