AOP服务切面编程初探

1.添加依赖包

<PackageReference Include="Autofac.Extras.DynamicProxy" Version="7.1.0" />

2.设计AOP日志信息类【AOPLogInfo】

public class AOPLogInfo
{
  /// <summary>
  /// 请求时间
  /// </summary>
  public string RequestTime { get; set; } = string.Empty;

  /// <summary>
  /// 操作人员
  /// </summary>
  public string OpUserName { get; set; } = string.Empty;

  /// <summary>
  /// 请求方法名
  /// </summary>
  public string RequestMethodName { get; set; } = string.Empty;

  /// <summary>
  /// 请求参数名
  /// </summary>
  public string RequestParamsName { get; set; } = string.Empty;

  /// <summary>
  /// 请求参数数据JSON
  /// </summary>
  public string RequestParamsData { get; set; } = string.Empty;

  /// <summary>
  /// 请求响应间隔时间
  /// </summary>
  public string ResponseIntervalTime { get; set; } = string.Empty;

  /// <summary>
  /// 响应时间
  /// </summary>
  public string ResponseTime { get; set; } = string.Empty;

  /// <summary>
  /// 响应结果
  /// </summary>
  public string ResponseJsonData { get; set; } = string.Empty;
}

3.设计拦截器【ServiceAOP】

/// <summary>
/// 拦截器AOP 继承IInterceptor接口
/// </summary>
public class ServiceAOP : IInterceptor
{

    /// <summary>
    /// 实例化IInterceptor唯一方法 
    /// </summary>
    /// <param name="invocation">包含被拦截方法的信息</param>
    public void Intercept(IInvocation invocation)
    {
        string json;
        try
        {
            json = JsonConvert.SerializeObject(invocation.Arguments);
        }
        catch (Exception ex)
        {
            json = "无法序列化，可能是兰姆达表达式等原因造成，按照框架优化代码" + ex.ToString();
        }

        DateTime startTime = DateTime.Now;
        AOPLogInfo apiLogAopInfo = new AOPLogInfo
        {
            RequestTime = startTime.ToString("yyyy-MM-dd hh:mm:ss fff"),
            OpUserName = "",
            RequestMethodName = invocation.Method.Name,
            RequestParamsName = string.Join(", ", invocation.Arguments.Select(a => (a ?? "").ToString()).ToArray()),
            ResponseJsonData = json
        };

        try
        {
            //在被拦截的方法执行完毕后 继续执行当前方法，注意是被拦截的是异步的
            invocation.Proceed();


            // 异步获取异常，先执行
            if (IsAsyncMethod(invocation.Method))
            {

                //Wait task execution and modify return value
                if (invocation.Method.ReturnType == typeof(Task))
                {
                    invocation.ReturnValue = InternalAsyncHelper.AwaitTaskWithPostActionAndFinally(
                        (Task)invocation.ReturnValue,
                        async () => await SuccessAction(invocation, apiLogAopInfo, startTime), /*成功时执行*/
                        ex =>
                        {
                            LogEx(ex, apiLogAopInfo);
                        });
                }
                //Task<TResult>
                else
                {
                    invocation.ReturnValue = InternalAsyncHelper.CallAwaitTaskWithPostActionAndFinallyAndGetResult(
                        invocation.Method.ReturnType.GenericTypeArguments[0],
                        invocation.ReturnValue,
                        async (o) => await SuccessAction(invocation, apiLogAopInfo, startTime, o), /*成功时执行*/
                        ex =>
                        {
                            LogEx(ex, apiLogAopInfo);
                        });
                }

            }
            else
            {
                // 同步1
                string jsonResult;
                try
                {
                    jsonResult = JsonConvert.SerializeObject(invocation.ReturnValue);
                }
                catch (Exception ex)
                {
                    jsonResult = "无法序列化，可能是兰姆达表达式等原因造成，按照框架优化代码" + ex.ToString();
                }

                DateTime endTime = DateTime.Now;
                string ResponseTime = (endTime - startTime).Milliseconds.ToString();
                apiLogAopInfo.ResponseTime = endTime.ToString("yyyy-MM-dd hh:mm:ss fff");
                apiLogAopInfo.ResponseIntervalTime = ResponseTime + "ms";
                apiLogAopInfo.ResponseJsonData = jsonResult;
                Console.WriteLine(JsonConvert.SerializeObject(apiLogAopInfo));
            }
        }
        catch (Exception ex)
        {
            LogEx(ex, apiLogAopInfo);
            throw;
        }
    }

    private async Task SuccessAction(IInvocation invocation, AOPLogInfo apiLogAopInfo, DateTime startTime, object o = null)
    {
        DateTime endTime = DateTime.Now;
        string ResponseTime = (endTime - startTime).Milliseconds.ToString();
        apiLogAopInfo.ResponseTime = endTime.ToString("yyyy-MM-dd hh:mm:ss fff");
        apiLogAopInfo.ResponseIntervalTime = ResponseTime + "ms";
        apiLogAopInfo.ResponseJsonData = JsonConvert.SerializeObject(o);

        await Task.Run(() =>
        {
            //Console.WriteLine("执行成功-->" + JsonConvert.SerializeObject(apiLogAopInfo));
        });
    }

    private void LogEx(Exception ex, AOPLogInfo dataIntercept)
    {
        if (ex != null)
        {
            Console.WriteLine("error!!!:" + ex.Message + JsonConvert.SerializeObject(dataIntercept));
        }
    }


    public static bool IsAsyncMethod(MethodInfo method)
    {
        return
            method.ReturnType == typeof(Task) ||
            method.ReturnType.IsGenericType && method.ReturnType.GetGenericTypeDefinition() == typeof(Task<>);
    }
}


internal static class InternalAsyncHelper
{
    public static async Task AwaitTaskWithPostActionAndFinally(Task actualReturnValue, Func<Task> postAction, Action<Exception> finalAction)
    {
        Exception exception = null;

        try
        {
            await actualReturnValue;
            await postAction();
        }
        catch (Exception ex)
        {
            exception = ex;
        }
        finally
        {
            finalAction(exception);
        }
    }

    public static async Task<T> AwaitTaskWithPostActionAndFinallyAndGetResult<T>(Task<T> actualReturnValue, Func<object, Task> postAction,
    Action<Exception> finalAction)
    {
        Exception exception = null;
        try
        {
            var result = await actualReturnValue;
            await postAction(result);
            return result;
        }
        catch (Exception ex)
        {
            exception = ex;
            throw;
        }
        finally
        {
            finalAction(exception);
        }
    }

    public static object CallAwaitTaskWithPostActionAndFinallyAndGetResult(Type taskReturnType, object actualReturnValue,
         Func<object, Task> action, Action<Exception> finalAction)
    {
        return typeof(InternalAsyncHelper)
            .GetMethod("AwaitTaskWithPostActionAndFinallyAndGetResult", BindingFlags.Public | BindingFlags.Static)
            .MakeGenericMethod(taskReturnType)
            .Invoke(null, new object[] { actualReturnValue, action, finalAction });
    }
}

4.将拦截器注册或挂载到服务中

var aopType = new List<Type> { typeof(ServiceAOP) };
builder.RegisterType<ServiceAOP>();