using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Data;

using System.Collections.Specialized;

​

using System.Text.Json;

using System.Text.Json.Serialization;

​

using NUnit.Framework; // Throws NUnit.Framework.AssertionException

​

//https://stackoverflow.com/questions/73347231/system-text-json-custom-deserialization-for-dictionarystring-dictionarystring

​

#nullable enable

​

    public class StringCollectionConverter : JsonConverter<StringCollection>

    {

        public override StringCollection? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) =>

            JsonSerializer.Deserialize<List<string>>(ref reader, options)?.Aggregate(new StringCollection(), (sc, s) => { sc.Add(s); return sc; });

        public override void Write(Utf8JsonWriter writer, StringCollection value, JsonSerializerOptions options) => 

            JsonSerializer.Serialize(writer, value.Cast<string>(), options);

    }

​

    public record AclRecord 

    {

        public Dictionary<string, Dictionary<string, Dictionary<string, StringCollection>>> ACL { get; set; }

    }

​

    class TestClass

    {

        public static void Test()

        {

            TestBasic();

            TestAclRecord();

        }

        public static void TestBasic()

        {

            var sc = new StringCollection();

            sc.AddRange(new []{"a", "b", null!, "c\n\0c" });

            var options = new JsonSerializerOptions { Converters = { new StringCollectionConverter() } };

            var json = JsonSerializer.Serialize(sc, options);

            Console.WriteLine(json);

            var sc2 = JsonSerializer.Deserialize<StringCollection>(json, options);

            var json2 = JsonSerializer.Serialize(sc2);

​

            Console.WriteLine(json2);

            Assert.AreEqual(json, json2);

            Assert.That(sc.Cast<string>().SequenceEqual(sc2!.Cast<string>()));

        }

        static void TestAclRecord()

        {

            var json = GetJson();

            var options = new JsonSerializerOptions 

            { 

                Converters = { new StringCollectionConverter(), /* Add other converters here */ },

                // Set other options below

                WriteIndented = true,

            };

            var model = JsonSerializer.Deserialize<AclRecord>(json, options);

            var json2 = JsonSerializer.Serialize(model, options);

            Console.WriteLine("Re-serialized {0};", model);

            Console.WriteLine(json2);

            Assert.AreEqual(json, json2);

        }

        static string GetJson() => @"{

  ""ACL"": {

    ""granted"": {

      ""Business"": {

        ""Delete"": [

          ""Customer1"",

          ""Customer2""

        ]

      },

      ""Account"": {

        ""Create"": [

          ""Customer1"",

          ""Customer3""

        ]

      }

    }

  }

}";

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: {0} ({1}), {2}", System.Runtime.InteropServices.RuntimeInformation.FrameworkDescription , Environment.Version, Environment.OSVersion);

            Console.WriteLine("System.Text.Json version: " + typeof(JsonSerializer).Assembly.FullName);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Failed with unhandled exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​