.Net Core3.0 WebApi 项目框架搭建 十五：基于AOP的切面redis缓存

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更新Redis缓存接口

在之前的redis缓存博客中我们定义了redis操作接口和实现，在实际项目开发中，我又对它进行了修改，主要是增加了异步和批量删除的接口。修改Common下的Redis文件夹的IRedisCacheManager文件和RedisCacheManager增加以下接口和方法。

IRedisCacheManager：

        //获取 Reids 缓存值
        Task<string> GetValueAsync(string key);

        //获取值，并序列化
        Task<TEntity> GetAsync<TEntity>(string key);

        //保存
        Task SetAsync(string key, object value, TimeSpan cacheTime);

        //判断是否存在
        Task<bool> GetAsync(string key);

        //移除某一个缓存值
        Task RemoveAsync(string key);

        //根据关键字移除
        Task RemoveByKey(string key);

        //全部清除
        Task ClearAsync();

RedisCacheManager：

        public async Task ClearAsync()
        {
            foreach (var endPoint in this.GetRedisConnection().GetEndPoints())
            {
                var server = this.GetRedisConnection().GetServer(endPoint);
                foreach (var key in server.Keys())
                {
                    await redisConnection.GetDatabase().KeyDeleteAsync(key);
                }
            }
        }

        public async Task<bool> GetAsync(string key)
        {
            return await redisConnection.GetDatabase().KeyExistsAsync(key);
        }

        public async Task<string> GetValueAsync(string key)
        {
            return await redisConnection.GetDatabase().StringGetAsync(key);
        }

        public async Task<TEntity> GetAsync<TEntity>(string key)
        {
            var value = await redisConnection.GetDatabase().StringGetAsync(key);
            if (value.HasValue)
            {
                //需要用的反序列化，将Redis存储的Byte[]，进行反序列化
                return SerializeHelper.Deserialize<TEntity>(value);
            }
            else
            {
                return default;
            }
        }

        public async Task RemoveAsync(string key)
        {
            await redisConnection.GetDatabase().KeyDeleteAsync(key);
        }

        public async Task RemoveByKey(string key)
        {
            var redisResult = await redisConnection.GetDatabase().ScriptEvaluateAsync(LuaScript.Prepare(
                //Redis的keys模糊查询：
                " local res = redis.call('KEYS', @keypattern) " +
                " return res "), new { @keypattern = key });

            if (!redisResult.IsNull)
            {
                var keys = (string[])redisResult;
                foreach (var k in keys)
                    redisConnection.GetDatabase().KeyDelete(k);

            }
        }

        public async Task SetAsync(string key, object value, TimeSpan cacheTime)
        {
            if (value != null)
            {
                //序列化，将object值生成RedisValue
                await redisConnection.GetDatabase().StringSetAsync(key, SerializeHelper.Serialize(value), cacheTime);
            }
        }

        public async Task<bool> SetValueAsync(string key, byte[] value)
        {
            return await redisConnection.GetDatabase().StringSetAsync(key, value, TimeSpan.FromSeconds(120));
        }

定义缓存特性

Common层新增Attributes文件夹，并新建CachingAttribute来定义我们的redis缓存特性，有了这个特性，我们就可以控制方法是否需要缓存到redis。

    /// <summary>
    /// 这个Attribute就是使用时候的验证，把它添加到要缓存数据的方法中，即可完成缓存的操作。
    /// </summary>
    [AttributeUsage(AttributeTargets.Method, Inherited = true)]
    public class CachingAttribute : Attribute
    {
        //过期时间
        public int AbsoluteExpiration { get; set; }
       /// <summary>
       /// 自定义key
       /// </summary>
        public string CustomKeyValue { get; set; }
        /// <summary>
        /// 是否删除
        /// </summary>
        public bool IsDelete { get; set; } = false;
    }

定义Redis切面拦截器

在主工程新加AOP文件夹，新建CacheAOPbase和RedisCacheAOP文件

public abstract class CacheAOPbase : IInterceptor
    {
        /// <summary>
        /// AOP的拦截方法
        /// </summary>
        /// <param name="invocation"></param>
        public abstract void Intercept(IInvocation invocation);

        /// <summary>
        /// 自定义缓存的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();//获取参数列表，最多三个

            string key = $"{typeName}:{methodName}:";
            foreach (var param in methodArguments)
            {
                key = $"{key}{param}:";
            }

            return key.TrimEnd(':');
        }

        /// <summary>
        /// object 转 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这类
                    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这类的
                {
                    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这种
                {
                    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)这类
                    return ResolveLinqToObject(unary.Operand, false);
                if (unary.Operand is MemberExpression && unary.NodeType == ExpressionType.Not)//解析x=>!x.isDeletion这样的 
                {
                    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这样的 
            {
                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)这类
            {
                MethodCallExpression methodcall = expression as MethodCallExpression;
                return ResolveLinqToObject(methodcall, true);
            }
            //已经修改过代码body应该不会是null值了
            if (!(expression is BinaryExpression body))
                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)
        {
            return expressiontype switch
            {
                ExpressionType.And => "and",
                ExpressionType.AndAlso => "and",
                ExpressionType.Or => "or",
                ExpressionType.OrElse => "or",
                ExpressionType.Equal => "=",
                ExpressionType.NotEqual => "<>",
                ExpressionType.LessThan => "<",
                ExpressionType.LessThanOrEqual => "<=",
                ExpressionType.GreaterThan => ">",
                ExpressionType.GreaterThanOrEqual => ">=",
                _ => throw new Exception(string.Format("不支持{0}此种运算符查找！" + 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("不支持{0}方法的查找！", 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 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;
        }

    }

CacheAOPbase