using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.IO;

using System.Data;

​

using System.Text.Json;

using System.Text.Json.Serialization;

using System.Text.Json.Nodes;

using System.Text.Json.Serialization.Metadata;

​

using System.Security.Cryptography;

using System.Web;

​

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

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//https://stackoverflow.com/questions/72592246/how-do-i-add-lexicographical-sort-in-this-system-text-json-serialization-way?noredirect=1#comment128232022_72592246

​

#nullable enable

​

    internal class MexcSubPersonalPayload

    {

        private readonly string _apiSecret;

​

        public MexcSubPersonalPayload(string apiKey, string apiSecret)

        {

            ApiKey = apiKey;

            _apiSecret = apiSecret;

        }

​

        [JsonPropertyName("op")]

        [JsonPropertyOrder(1)]

        public string Operation => "sub.personal";

​

        [JsonPropertyName("api_key")]

        [JsonPropertyOrder(2)]

        public string ApiKey { get; }

​

        [JsonPropertyName("sign")]

        [JsonPropertyOrder(3)]

        public string Signature => Sign(ToString());

​

        [JsonPropertyName("req_time")]

        [JsonPropertyOrder(4)]

        public long RequestTime => DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();

​

        private string Sign(string payload)

        {

            if (string.IsNullOrWhiteSpace(payload))

            {

                return string.Empty;

            }

​

            using var md5 = MD5.Create();

            var sourceBytes = Encoding.UTF8.GetBytes(payload);

            var hash = md5.ComputeHash(sourceBytes);

            return Convert.ToHexString(hash);

        }

​

        public override string ToString()

        {

            return $"api_key={HttpUtility.UrlEncode(ApiKey)}&req_time={RequestTime}&op={Operation}&api_secret={HttpUtility.UrlEncode(_apiSecret)}";

        }

    }

​

    public static partial class JsonExtensions

    {

        public static Action<JsonTypeInfo> AlphabetizeProperties(Type type)

        {

            return typeInfo =>

            {

                if (typeInfo.Kind != JsonTypeInfoKind.Object || !type.IsAssignableFrom(typeInfo.Type))

                    return;

                AlphabetizeProperties()(typeInfo);

            };

        }

        public static Action<JsonTypeInfo> AlphabetizeProperties()

        {

            return static typeInfo =>

            {

                if (typeInfo.Kind != JsonTypeInfoKind.Object)

                    return;

                var properties = typeInfo.Properties.OrderBy(p => p.Name, StringComparer.Ordinal).ToList();

                typeInfo.Properties.Clear();

                for (int i = 0; i < properties.Count; i++)

                {

                    properties[i].Order = i;

                    typeInfo.Properties.Add(properties[i]);

                }

            };

        }

    }

​

    class TestClass

    {

        static readonly string _apiKey = "foo";

        static readonly string _apiSecret = "bar";

        public static void Test()

        {

            var payload = new MexcSubPersonalPayload(_apiKey, _apiSecret);

            var options = new JsonSerializerOptions

            {

                TypeInfoResolver = new DefaultJsonTypeInfoResolver

                {

                    Modifiers = { JsonExtensions.AlphabetizeProperties() },

                },

            };

            var request = JsonSerializer.Serialize(payload, options);

            Console.WriteLine(request);

            var keys = JsonNode.Parse(request)!.AsObject().AsDictionary().Keys;

            Assert.That(keys.SequenceEqual(keys.OrderBy(n => n, StringComparer.Ordinal)));

        }   

    }

​

    public static partial class JsonExtensions

    {

        public static IDictionary<String, JsonNode?> AsDictionary(this JsonObject obj) => obj;

    }

​

    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();

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            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

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

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​