/// <summary>
/// 执行前置拦截器
/// </summary>
/// <param name="invocation"></param>
private async Task <Tuple <List <AspectPointAttribute>, List <AspectInvokeAttribute>, Exception> > BeforeInterceptAttribute(IInvocation invocation)
{
//先从缓存里面拿到这个方法时候打了继承AspectInvokeAttribute的标签
if (!_cache.CacheList.TryGetValue(invocation.MethodInvocationTarget, out var Attributes) || Attributes == null || !Attributes.Any())
{
//动态泛型类
if (!invocation.MethodInvocationTarget.DeclaringType.GetTypeInfo().IsGenericType || (!_cache.DynamicCacheList.TryGetValue(invocation.MethodInvocationTarget.GetMethodInfoUniqueName(), out var AttributesDynamic) || AttributesDynamic == null || !AttributesDynamic.Any()))
{
return(null);
}
Attributes = AttributesDynamic;
}
var aspectContext = new AspectContext(_component, invocation);
Exception ex = null;
try
{
foreach (var attribute in Attributes)
{
//如果一个方法上面既有AspectAroundAttribute 又有 AspectBeforeAttribute 的话 按照下面的优先级 抛弃 AspectBeforeAttribute
switch (attribute)
{
case AspectAroundAttribute aspectAroundAttribute:
await aspectAroundAttribute.Before(aspectContext);
break;
case AspectBeforeAttribute aspectBeforeAttribute:
await aspectBeforeAttribute.Before(aspectContext);
break;
}
}
}
catch (Exception e)
{
ex = e;
}
return(new Tuple <List <AspectPointAttribute>, List <AspectInvokeAttribute>, Exception>(Attributes.OfType <AspectPointAttribute>().ToList(), Attributes, ex));
}
private async Task AfterInterceptAttribute(List <AspectInvokeAttribute> Attributes, IInvocation invocation, Exception exp)
{
var aspectContext = new AspectContext(_component, invocation, exp);
foreach (var attribute in Attributes)
{
switch (attribute)
{
case AspectAroundAttribute aspectAroundAttribute:
await aspectAroundAttribute.After(aspectContext);
break;
case AspectAfterAttribute aspectAfterAttribute:
await aspectAfterAttribute.After(aspectContext);
break;
}
}
}
/// <summary>
/// 有返回值拦截器
/// </summary>
/// <typeparam name="TResult"></typeparam>
/// <param name="invocation"></param>
/// <param name="proceedInfo"></param>
/// <param name="proceed"></param>
/// <returns></returns>
protected override async Task <TResult> InterceptAsync <TResult>(IInvocation invocation, IInvocationProceedInfo proceedInfo, Func <IInvocation, IInvocationProceedInfo, Task <TResult> > proceed)
{
var attribute = await BeforeInterceptAttribute(invocation);
try
{
TResult r;
if (attribute == null)
{
r = await proceed(invocation, proceedInfo);
return(r);
}
if (attribute.Item3 != null)
{
await AfterInterceptAttribute(attribute.Item2, invocation, attribute.Item3);
throw attribute.Item3;
}
if (attribute.Item1 == null || !attribute.Item1.Any())
{
r = await proceed(invocation, proceedInfo);
}
else
{
AspectMiddlewareBuilder builder = new AspectMiddlewareBuilder();
foreach (var pointAspect in attribute.Item1)
{
builder.Use(next => async ctx =>
{
await pointAspect.OnInvocation(ctx, next);
//如果有拦截器设置 ReturnValue 那么就直接拿这个作为整个拦截器的方法返回值
if (ctx.InvocationContext.ReturnValue != null)
{
ctx.Result = ctx.InvocationContext.ReturnValue;
}
});
}
builder.Use(next => async ctx =>
{
ctx.Result = await proceed(invocation, proceedInfo);
invocation.ReturnValue = ctx.Result; //原方法的执行返回值
});
var aspectfunc = builder.Build();
var aspectContext = new AspectContext(_component, invocation);
await aspectfunc(aspectContext);
r = (TResult)aspectContext.Result;
}
await AfterInterceptAttribute(attribute.Item2, invocation, null);
return(r);
}
catch (Exception e)
{
if (attribute != null)
{
await AfterInterceptAttribute(attribute.Item2, invocation, e);
}
throw;
}
}
/// <summary> /// 后置执行 /// </summary> /// <param name="aspectContext"></param> public abstract Task After(AspectContext aspectContext);
/// <summary> /// 前置执行 /// </summary> /// <param name="aspectContext"></param> public abstract Task Before(AspectContext aspectContext);
/// <summary> /// 拦截器 /// </summary> /// <param name="aspectContext">拦截上下文</param> /// <param name="_next">下一个拦截器 最后一个是执行被拦截的方法</param> /// <returns></returns> public abstract Task OnInvocation(AspectContext aspectContext, AspectDelegate _next);