.NET Core 3.x 基於Autofac的AOP快取
阿新 • • 發佈：2020-09-14
一、依賴包
二、定義一個簡單的快取介面
/// <summary>
/// 簡單的快取介面，只有查詢和新增，以後會進行擴充套件
/// </summary>
public interface ICaching
{
object Get(string cacheKey);
void Set(string cacheKey, object cacheValue, TimeSpan absoluteExpirationRelativeToNow);
}
三、實現快取介面
public class MemoryCaching : ICaching { private IMemoryCache _cache; public MemoryCaching(IMemoryCache cache) { _cache = cache; } public object Get(string cacheKey) { return _cache.Get(cacheKey); } public void Set(string cacheKey, object cacheValue, TimeSpan absoluteExpirationRelativeToNow) { _cache.Set(cacheKey, cacheValue, absoluteExpirationRelativeToNow); } }
四、定義快取屬性
/// <summary> /// 這個Attribute就是使用時候的驗證，把它新增到要快取資料的方法中，即可完成快取的操作。 /// 往Server層方法上新增即可使用 [CachingAttribute(AbsoluteExpiration = 10)] //使用快取AOP 快取10分鐘 /// </summary> [AttributeUsage(AttributeTargets.Method, Inherited = true)] public class CachingAttribute : Attribute { /// <summary> /// 快取絕對過期時間（分鐘） /// </summary> public int AbsoluteExpiration { get; set; } = 30; }
五、AOP實現
/// <summary> /// 面向切面的快取使用 /// </summary> public class BlogCacheAOP : IInterceptor { //通過注入的方式，把快取操作介面通過建構函式注入 private readonly ICaching _cache; public BlogCacheAOP(ICaching cache) { _cache = cache; } //Intercept方法是攔截的關鍵所在，也是IInterceptor介面中的唯一定義 public void Intercept(IInvocation invocation) { var method = invocation.MethodInvocationTarget ?? invocation.Method; //對當前方法的特性驗證 var qCachingAttribute = this.GetQCachingAttributeInfo(invocation.MethodInvocationTarget ?? invocation.Method); if (qCachingAttribute != null) { ProceedCaching(invocation, qCachingAttribute); } else { invocation.Proceed();//直接執行被攔截方法 } } private CachingAttribute GetQCachingAttributeInfo(MethodInfo method) { return method.GetCustomAttributes(true).FirstOrDefault(x => x.GetType() == typeof(CachingAttribute)) as CachingAttribute; } private void ProceedCaching(IInvocation invocation, CachingAttribute attribute) { //獲取自定義快取鍵 var cacheKey = CustomCacheKey(invocation); //根據key獲取相應的快取值 var cacheValue = _cache.Get(cacheKey); if (cacheValue != null) { //將當前獲取到的快取值，賦值給當前執行方法 invocation.ReturnValue = cacheValue; return; } //去執行當前的方法 invocation.Proceed(); //存入快取 if (!string.IsNullOrWhiteSpace(cacheKey)) { _cache.Set(cacheKey, invocation.ReturnValue, TimeSpan.FromMinutes(attribute.AbsoluteExpiration)); } } /// <summary> /// 自定義快取的key /// </summary> /// <param name="invocation"></param> /// <returns></returns> protected string CustomCacheKey(IInvocation invocation) { var typeName = invocation.TargetType.Name; var methodName = invocation.Method.Name; var methodArguments = invocation.Arguments.Select(GetArgumentValue).Take(3).ToList();//獲取引數列表，最多三個 string key = $"{typeName}:{methodName}:"; foreach (var param in methodArguments) { key = $"{key}{param}:"; } return key.TrimEnd(':'); } /// <summary> /// object 轉 string /// </summary> /// <param name="arg"></param> /// <returns></returns> protected static string GetArgumentValue(object arg) { if (arg is DateTime || arg is DateTime?) return ((DateTime)arg).ToString("yyyyMMddHHmmss"); if (arg is string || arg is ValueType || arg is Nullable) return arg.ToString(); if (arg != null) { if (arg is Expression) { var obj = arg as Expression; var result = Resolve(obj); return Common.Helper.MD5Helper.MD5Encrypt16(result); } else if (arg.GetType().IsClass) { return Common.Helper.MD5Helper.MD5Encrypt16(Newtonsoft.Json.JsonConvert.SerializeObject(arg)); } } return string.Empty; } private static string Resolve(Expression expression) { if (expression is LambdaExpression) { LambdaExpression lambda = expression as LambdaExpression; expression = lambda.Body; return Resolve(expression); } if (expression is BinaryExpression) { BinaryExpression binary = expression as BinaryExpression; if (binary.Left is MemberExpression && binary.Right is ConstantExpression)//解析x=>x.Name=="123" x.Age==123這類 return ResolveFunc(binary.Left, binary.Right, binary.NodeType); if (binary.Left is MethodCallExpression && binary.Right is ConstantExpression)//解析x=>x.Name.Contains("xxx")==false這類的 { object value = (binary.Right as ConstantExpression).Value; return ResolveLinqToObject(binary.Left, value, binary.NodeType); } if ((binary.Left is MemberExpression && binary.Right is MemberExpression) || (binary.Left is MemberExpression && binary.Right is UnaryExpression))//解析x=>x.Date==DateTime.Now這種 { LambdaExpression lambda = Expression.Lambda(binary.Right); Delegate fn = lambda.Compile(); ConstantExpression value = Expression.Constant(fn.DynamicInvoke(null), binary.Right.Type); return ResolveFunc(binary.Left, value, binary.NodeType); } } if (expression is UnaryExpression) { UnaryExpression unary = expression as UnaryExpression; if (unary.Operand is MethodCallExpression)//解析!x=>x.Name.Contains("xxx")或!array.Contains(x.Name)這類 return ResolveLinqToObject(unary.Operand, false); if (unary.Operand is MemberExpression && unary.NodeType == ExpressionType.Not)//解析x=>!x.isDeletion這樣的 { ConstantExpression constant = Expression.Constant(false); return ResolveFunc(unary.Operand, constant, ExpressionType.Equal); } } if (expression is MemberExpression && expression.NodeType == ExpressionType.MemberAccess)//解析x=>x.isDeletion這樣的 { MemberExpression member = expression as MemberExpression; ConstantExpression constant = Expression.Constant(true); return ResolveFunc(member, constant, ExpressionType.Equal); } if (expression is MethodCallExpression)//x=>x.Name.Contains("xxx")或array.Contains(x.Name)這類 { MethodCallExpression methodcall = expression as MethodCallExpression; return ResolveLinqToObject(methodcall, true); } var body = expression as BinaryExpression; //已經修改過程式碼body應該不會是null值了 if (body == null) return string.Empty; var Operator = GetOperator(body.NodeType); var Left = Resolve(body.Left); var Right = Resolve(body.Right); string Result = string.Format("({0} {1} {2})", Left, Operator, Right); return Result; } private static string GetOperator(ExpressionType expressiontype) { switch (expressiontype) { case ExpressionType.And: return "and"; case ExpressionType.AndAlso: return "and"; case ExpressionType.Or: return "or"; case ExpressionType.OrElse: return "or"; case ExpressionType.Equal: return "="; case ExpressionType.NotEqual: return "<>"; case ExpressionType.LessThan: return "<"; case ExpressionType.LessThanOrEqual: return "<="; case ExpressionType.GreaterThan: return ">"; case ExpressionType.GreaterThanOrEqual: return ">="; default: throw new Exception(string.Format("不支援{0}此種運算子查詢！" + expressiontype)); } } private static string ResolveFunc(Expression left, Expression right, ExpressionType expressiontype) { var Name = (left as MemberExpression).Member.Name; var Value = (right as ConstantExpression).Value; var Operator = GetOperator(expressiontype); return Name + Operator + Value ?? "null"; } private static string ResolveLinqToObject(Expression expression, object value, ExpressionType? expressiontype = null) { var MethodCall = expression as MethodCallExpression; var MethodName = MethodCall.Method.Name; switch (MethodName) { case "Contains": if (MethodCall.Object != null) return Like(MethodCall); return In(MethodCall, value); case "Count": return Len(MethodCall, value, expressiontype.Value); case "LongCount": return Len(MethodCall, value, expressiontype.Value); default: throw new Exception(string.Format("不支援{0}方法的查詢！", MethodName)); } } private static string In(MethodCallExpression expression, object isTrue) { var Argument1 = (expression.Arguments[0] as MemberExpression).Expression as ConstantExpression; var Argument2 = expression.Arguments[1] as MemberExpression; var Field_Array = Argument1.Value.GetType().GetFields().First(); object[] Array = Field_Array.GetValue(Argument1.Value) as object[]; List<string> SetInPara = new List<string>(); for (int i = 0; i < Array.Length; i++) { string Name_para = "InParameter" + i; string Value = Array[i].ToString(); SetInPara.Add(Value); } string Name = Argument2.Member.Name; string Operator = Convert.ToBoolean(isTrue) ? "in" : " not in"; string CompName = string.Join(",", SetInPara); string Result = string.Format("{0} {1} ({2})", Name, Operator, CompName); return Result; } private static string Like(MethodCallExpression expression) { var Temp = expression.Arguments[0]; LambdaExpression lambda = Expression.Lambda(Temp); Delegate fn = lambda.Compile(); var tempValue = Expression.Constant(fn.DynamicInvoke(null), Temp.Type); string Value = string.Format("%{0}%", tempValue); string Name = (expression.Object as MemberExpression).Member.Name; string Result = string.Format("{0} like {1}", Name, Value); return Result; } private static string Len(MethodCallExpression expression, object value, ExpressionType expressiontype) { object Name = (expression.Arguments[0] as MemberExpression).Member.Name; string Operator = GetOperator(expressiontype); string Result = string.Format("len({0}){1}{2}", Name, Operator, value.ToString()); return Result; } }
六、注入快取
/// <summary>
/// 快取服務啟動
/// </summary>
public static class MemoryCacheSetup
{
public static void AddMemoryCacheSetup(this IServiceCollection services)
{
if (services == null) throw new ArgumentNullException(nameof(services));
services.AddScoped<ICaching, MemoryCaching>();
services.AddSingleton<IMemoryCache>(factory =>
{
var cache = new MemoryCache(new MemoryCacheOptions());
return cache;
});
}
}
public class Startup
{ // This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{//注入快取
services.AddMemoryCacheSetup();
}
}
七、註冊AOP
public class Startup
{
public void ConfigureContainer(ContainerBuilder builder)
{
//other ...// AOP
var cacheType = new List<Type>();
builder.RegisterType<BlogCacheAOP>();
cacheType.Add(typeof(BlogCacheAOP));
// 獲取 Service.dll 程式集服務，並註冊
var assemblysServices = Assembly.LoadFrom(servicesDllFile);
builder.RegisterAssemblyTypes(assemblysServices)
.AsImplementedInterfaces()
.InstancePerDependency()
.EnableInterfaceInterceptors()//引用Autofac.Extras.DynamicProxy;
.InterceptedBy(cacheType.ToArray());//允許將攔截器服務的列表分配給註冊。
//other ...
}
}
八、使用
服務層在需要快取的方法上新增屬性，就OK了
public class BlogArticleServices : BaseServices<BlogArticle>, IBlogArticleServices
{
IBlogArticleRepository _dal;
public BlogArticleServices(IBlogArticleRepository dal)
{
this._dal = dal;
base.BaseDal = dal;
}
/// <summary>
/// 獲取部落格列表
/// </summary>
/// <returns></returns>
[CachingAttribute(AbsoluteExpiration = 10)] //使用快取AOP 快取10分鐘
public async Task<List<BlogArticle>> getBlogs()
{
var blogList = await _dal.Query(a => a.bID > 0, a => a.bID);
return blogList;
}
}
九、執行程式碼
第一次進入沒有快取，走 set 快取10分鐘
第二次進入，有快取得到快取直接返回