GraphQL 既是一种用于 API 的查询语言也是一个满足你数据查询的运行时。GraphQL 对你的 API 中的数据提供了一套易于理解的完整描述，使得客户端能够准确地获得它需要的数据，而且没有任何冗余，也让 API 更容易地随着时间推移而演进，还能用于构建强大的开发者工具。

                                        ——出自 https://graphql.cn

HotChocolate中可以通过定义Attribute来增加通用性处理功能，之前博文中用过UsePaging分页，UseFiltering过滤，UseSorting排序，我们也可以自定义特性类来达到处理统一数据的作用，下面的例子就是一个脱敏的特性类，可以在使用特性类时告诉系统那些数据是不显示出来的，此类就会把数据变成等长的*号字符串来替换。

using HotChocolate;using HotChocolate.Data;using HotChocolate.Execution;using HotChocolate.Types;using HotChocolate.Types.Descriptors;using System;using System.Collections;using System.Collections.Generic;using System.Reflection;namespace GraphQLBase004{    class Program    {        static void Main(string[] args)        {            DescriptorAttributeDemo.Run();        }    }    public class DescriptorAttributeDemo    {        public static void Run()        {            var schema = SchemaBuilder.New()                .AddProjections()                .AddQueryType
    
     ()                .Create();            var executor = schema.MakeExecutable();            Console.WriteLine(executor.Execute("{ user{id userName password tel} }").ToJson());            Console.WriteLine("===============");            Console.WriteLine(executor.Execute("{ users{id userName password tel} }").ToJson());        }        /// 
     
        /// 查询类        /// 
        public class Query        {            [UseProjection]            [UseDesensitization(SensitiveFields = new string[] { "password", "tel" })]            public User GetUser()            {                return new User                {                    Id = 1,                    UserName = "gsw",                    Tel = "13453467114",                    Password = "111111"                };            }            [UseProjection]            [UseDesensitization(SensitiveFields = new string[] { "password", "tel" })]            public List
     
       GetUsers()            {                return new List
      
       (){                    new User                    {                        Id = 1,                        UserName = "gsw",                        Tel = "13453467114",                        Password = "111111"                    },                    new User                    {                        Id = 1,                        UserName = "gsw",                        Tel = "13453467114",                        Password = "111111"                    }                };            }        }        /// 
       
        /// 用户        /// 
        public class User        {            public int Id { get; set; }            public string UserName { get; set; }            public string Tel { get; set; }            public string Password { get; set; }        }        /// 
       
        /// 脱敏特性类        /// 
        public class UseDesensitizationAttribute : ObjectFieldDescriptorAttribute        {            public string[] SensitiveFields            {                get; set;            }            public override void OnConfigure(IDescriptorContext context, IObjectFieldDescriptor descriptor, MemberInfo member)            {                descriptor.Use(next => context =>                {                    var obj = context.GetType().GetMethod("Parent").MakeGenericMethod(context.ObjectType.RuntimeType).Invoke(context, new object[0]);                    var resultObj = (member as MethodInfo).Invoke(obj, new object[0]);                    foreach (var proName in SensitiveFields)                    {                        var resulttType = resultObj.GetType();                        //处理泛型集合                        if (resulttType.IsGenericType)                        {                            foreach (var resultItem in (resultObj as IList))                            {                                SetValue(proName, resultItem.GetType(), resultItem);                            }                        }                        else                        {                            SetValue(proName, resulttType, resultObj);                        }                        void SetValue(string proName, Type type, object resultObj)                        {                            var pro = type.GetProperty(proName, BindingFlags.IgnoreCase | BindingFlags.Instance | BindingFlags.Public);                            if (pro != null && pro.PropertyType.IsAssignableFrom(typeof(string)))                            {                                var len = pro.GetValue(resultObj).ToString()?.Length;                                pro.SetValue(resultObj, "".PadLeft(len.Value, '*'));                            }                        }                    }                    context.Result = resultObj;                    return next.Invoke(context);                });            }        }    }}
      
     
    

执行结果：