微软企业库5.0 学习之路——第九步、使用PolicyInjection模块进行AOP—PART4——建立自定义Call Handler实现用户操作日志记录

CREATE TABLE [dbo].[UserLog](
[ID] [int] IDENTITY(,) NOT NULL,--主键
[StudentId] [int] NOT NULL,--对应学生ID
[Message] [nvarchar]() NOT NULL,--操作消息
[LogDate] [datetime] NOT NULL,--记录时间
CONSTRAINT [PK_UserLog] PRIMARY KEY CLUSTERED
(
[ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Data;
using System.Data.Common;
using System.Linq;
using System.Text;using Microsoft.Practices.EnterpriseLibrary.Common.Configuration;
using Microsoft.Practices.EnterpriseLibrary.Data;
using Microsoft.Practices.Unity.InterceptionExtension;namespace EntLibStudy.Helper.EntLibExtension.PolicyInjectionExtension
{
[ConfigurationElementType(typeof(CustomCallHandlerData))]
public class UserLogCallHandler : ICallHandler
{
/// <summary>
/// 构造函数，此处不可省略，否则会导致异常
/// </summary>
/// <param name="attributes">配置文件中所配置的参数</param>
public UserLogCallHandler(NameValueCollection attributes)
{
//从配置文件中获取key，如不存在则指定默认key
this.Message = String.IsNullOrEmpty(attributes["Message"]) ? "" : attributes["Message"];
this.ParameterName = String.IsNullOrEmpty(attributes["ParameterName"]) ? "" : attributes["ParameterName"];
} /// <summary>
/// 构造函数，此构造函数是用于Attribute调用
/// </summary>
/// <param name="message">消息</param>
/// <param name="parameterName">参数名</param>
public UserLogCallHandler(string message, string parameterName)
{
this.Message = message;
this.ParameterName = parameterName;
} /// <summary>
/// 实现ICallHandler.Invoke方法，用于对具体拦截方法做相应的处理
/// </summary>
/// <param name="input"></param>
/// <param name="getNext"></param>
/// <returns></returns>
public IMethodReturn Invoke(IMethodInvocation input, GetNextHandlerDelegate getNext)
{
//检查参数是否存在
if (input == null) throw new ArgumentNullException("input");
if (getNext == null) throw new ArgumentNullException("getNext"); //开始拦截，此处可以根据需求编写具体业务逻辑代码 //调用具体方法
var result = getNext()(input, getNext);
//判断所拦截的方法返回值是否是bool类型，
//如果是bool则判断返回值是否为false,false:表示调用不成功，则直接返回方法不记录日志
if (result.ReturnValue.GetType() == typeof(bool))
{
if (Convert.ToBoolean(result.ReturnValue) == false)
{
return result;
}
}
//如果调用方法没有出现异常则记录操作日志
if (result.Exception == null)
{
//获取当前登录的用户名，从cookies中获取，如果采用的session记录，则更改为从session中获取
var uid = Utils.GetCookies("sid");
//如果未登录则抛出异常
if (String.IsNullOrEmpty(uid)) throw new Exception("用户未登录！"); //操作附加消息，用于获取操作的记录相关标识
var actionMessage = "";
object para = null;
//判断调用方法的主要参数名是否为空，不为空则从拦截的方法中获取参数对象
if (String.IsNullOrEmpty(this.ParameterName) == false)
{
para = input.Inputs[this.ParameterName];
}
//判断参数对象是否为null，不为null时则获取参数标识
//此处对应着具体参数的ToString方法，我已经在具体类中override了ToString方法
if (para != null)
{
actionMessage = " 编号:[" + para.ToString() + "]";
} //插入操作日志
Database db = DBHelper.CreateDataBase();
StringBuilder sb = new StringBuilder();
sb.Append("insert into UserLog(StudentId,Message,LogDate) values(@StudentId,@Message,@LogDate);");
DbCommand cmd = db.GetSqlStringCommand(sb.ToString());
db.AddInParameter(cmd, "@StudentId", DbType.Int32, uid);
db.AddInParameter(cmd, "@Message", DbType.String, this.Message + actionMessage);
db.AddInParameter(cmd, "@LogDate", DbType.DateTime, DateTime.Now);
db.ExecuteNonQuery(cmd);
}
//返回方法，拦截结束
return result;
} public string Message { get; set; } public string ParameterName { get; set; } private int _order = ;
public int Order
{
get
{
return _order;
}
set
{
_order = value;
}
}
}
}

public override string ToString()
{
return this.Id.ToString();
}

//操作附加消息，用于获取操作的记录相关标识
var actionMessage = "";
object para = null;
//判断调用方法的主要参数名是否为空，不为空则从拦截的方法中获取参数对象
if (String.IsNullOrEmpty(this.ParameterName) == false)
{
para = input.Inputs[this.ParameterName];
}
//判断参数对象是否为null，不为null时则获取参数标识
//此处对应着具体参数的ToString方法，我已经在具体类中override了ToString方法
if (para != null)
{
actionMessage = " 编号:[" + para.ToString() + "]";
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Practices.Unity;
using Microsoft.Practices.Unity.InterceptionExtension;namespace EntLibStudy.Helper.EntLibExtension.PolicyInjectionExtension
{
[AttributeUsage(AttributeTargets.Method)]
public class UserLogCallHandlerAttribute : HandlerAttribute
{
public UserLogCallHandlerAttribute(string message, string ParameterName)
{
this.Message = message;
this.ParameterName = ParameterName;
} public string Message { get; set; } public string ParameterName { get; set; } public override ICallHandler CreateHandler(IUnityContainer container)
{
//创建具体Call Handler，并调用
UserLogCallHandler handler = new UserLogCallHandler(this.Message, this.ParameterName); return handler;
}
}
}

/// <summary>
/// 构造函数，此构造函数是用于Attribute调用
/// </summary>
/// <param name="message">消息</param>
/// <param name="parameterName">参数名</param>
public UserLogCallHandler(string message, string parameterName)
{
this.Message = message;
this.ParameterName = parameterName;
}

/// <summary>
/// 构造函数，此处不可省略，否则会导致异常
/// </summary>
/// <param name="attributes">配置文件中所配置的参数</param>
public UserLogCallHandler(NameValueCollection attributes)
{
//从配置文件中获取key，如不存在则指定默认key
this.Message = String.IsNullOrEmpty(attributes["Message"]) ? "" : attributes["Message"];
this.ParameterName = String.IsNullOrEmpty(attributes["ParameterName"]) ? "" : attributes["ParameterName"];
}

[UserLogCallHandler("更新学生信息","student")]
public bool Update(Student student)
{
return studentService.Update(student);
}