using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Runtime.Serialization.Formatters;

using System.IO;

using System.Data;

using System.ComponentModel.DataAnnotations;

using System.Globalization;

using System.Reflection;

​

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Serialization;    

​

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

​

    //https://stackoverflow.com/questions/53278497/create-invalid-json-with-newtonsoft-allow-invalid-objects

    public class EsiObjConverter<T> : JsonConverter

    {

        const string EsiObjName = "EsiObj";

​

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)

        {

            var contract = serializer.ContractResolver.ResolveContract(value.GetType()) as JsonObjectContract;

            if (contract == null)

                throw new JsonSerializationException(string.Format("Non-object type {0}", value));

            writer.WriteStartObject();

            int propertyCount = 0;

            bool lastWasEsiProperty = false;

            foreach (var property in contract.Properties.Where(p => p.Readable && !p.Ignored))

            {

                if (property.UnderlyingName == EsiObjName && property.PropertyType == typeof(string))

                {

                    var esiValue = (string)property.ValueProvider.GetValue(value);

                    if (!string.IsNullOrEmpty(esiValue))

                    {

                        if (propertyCount > 0)

                        {

                            WriteValueDelimiter(writer);

                        }

                        writer.WriteWhitespace("\n");

                        writer.WriteRaw(esiValue);

                        // If it makes replacement easier, you could force the ESI string to be on its own line by calling

                        // writer.WriteWhitespace("\n");

​

                        propertyCount++;

                        lastWasEsiProperty = true;

                    }

                }

                else

                {

                    var propertyValue = property.ValueProvider.GetValue(value);

​

                    // Here you might check NullValueHandling, ShouldSerialize(), ...

​

                    if (propertyCount == 1 && lastWasEsiProperty)

                    {

                        WriteValueDelimiter(writer);

                    }

                    writer.WritePropertyName(property.PropertyName);

                    serializer.Serialize(writer, propertyValue);

​

                    propertyCount++;

                    lastWasEsiProperty = false;

                }

            }

            writer.WriteEndObject();

        }

​

        static void WriteValueDelimiter(JsonWriter writer)

        {

            var args = new object[0];

            // protected virtual void WriteValueDelimiter() 

            // https://www.newtonsoft.com/json/help/html/M_Newtonsoft_Json_JsonWriter_WriteValueDelimiter.htm

            // Since this is overridable by client code it is unlikely to be removed.

            writer.GetType().GetMethod("WriteValueDelimiter", BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic).Invoke(writer, args);

        }

​

        public override bool CanConvert(Type objectType)

        {

            return typeof(T).IsAssignableFrom(objectType);

        }

​

        public override bool CanRead { get { return false; } }

​

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)

        {

            throw new NotImplementedException();

        }

    }

​

    public class mApiResponseClass

    {

        public int value { get; set; }

        public string string1 { get; set; }

        public string EsiObj { get; set; }

        public List<string> Song { get; set; }

    }

​

    public class mApiResponseClassEsiFirst

    {

        public string EsiObj { get; set; }

        public int value { get; set; }

        public string string1 { get; set; }

        public List<string> Song { get; set; }

    }

​

    public class mApiResponseClassEsiLast

    {

        public int value { get; set; }

        public string string1 { get; set; }

        public List<string> Song { get; set; }

        public string EsiObj { get; set; }

    }

​

    public class mApiResponseClassEsiOnly

    {

        public string EsiObj { get; set; }

    }

​

    class TestClass

    {

        public static void Test()

        {

            var esiObj = new mApiResponseClass

            {

                value = 7,

                string1 = "woohoo",

                EsiObj = @"<esi:include src=""/something"" />",

                Song = new List<string> { "I am a small API","all i do is run","but from who?","nobody knows" },

            };

            var esiFirst = new mApiResponseClassEsiFirst

            {

                value = 7,

                string1 = "woohoo",

                EsiObj = @"<esi:include src=""/something"" />",

                Song = new List<string> { "I am a small API", "all i do is run", "but from who?", "nobody knows" },

            };

            var esiOnly = new mApiResponseClassEsiOnly

            {

                EsiObj = @"<esi:include src=""/something"" />",

            };

            var esiLast = new mApiResponseClassEsiLast

            {

                value = 7,

                string1 = "woohoo",

                EsiObj = @"<esi:include src=""/something"" />",

                Song = new List<string> { "I am a small API", "all i do is run", "but from who?", "nobody knows" },

            };

​

            TestSimpleAndUnquoted(esiObj);

​

            TestSimpleAndUnquoted(esiFirst);

​

            TestSimpleAndUnquoted(esiLast);

​

            TestSimpleAndUnquoted(esiOnly);

​

            Console.WriteLine();

​

            TestNested(esiObj);

​

            Console.WriteLine("Done tests");

        }

​

        private static void TestSimpleAndUnquoted<mApiResponseClass>(mApiResponseClass esiObj)

        {

            TestSimple(esiObj);

​

            TestWithoutNameQuoting(esiObj);

        }

​

        private static void TestSimple<mApiResponseClass>(mApiResponseClass obj)

        {

            Console.WriteLine("Serializing an instance of {0}:", obj);

​

            var settings = new JsonSerializerSettings

            {

                Converters = { new EsiObjConverter<mApiResponseClass>() },

            };

​

            var json = JsonConvert.SerializeObject(obj, Formatting.Indented, settings);

​

            Console.WriteLine(json);

        }

​

        private static void TestWithoutNameQuoting<mApiResponseClass>(mApiResponseClass obj)

        {

            Console.WriteLine("Serializing an instance of {0} without name quoting:", obj);

​

            var settings = new JsonSerializerSettings

            {

                Converters = { new EsiObjConverter<mApiResponseClass>() },

            };

​

            // Adapted from this answer https://stackoverflow.com/a/7555096

            // to https://stackoverflow.com/questions/7553516/json-net-serialize-property-name-without-quotes

            // by https://stackoverflow.com/users/893099/christophe-geers

​

            var stringWriter = new StringWriter();

            using (var writer = new JsonTextWriter(stringWriter))

            {

                writer.QuoteName = false;

                writer.Formatting = Formatting.Indented;

                writer.Indentation = 0;

                JsonSerializer.CreateDefault(settings).Serialize(writer, obj);

            }

​

            var json = stringWriter.ToString();

            Console.WriteLine(json);

        }

​

        private static void TestNested<mApiResponseClass>(mApiResponseClass obj)

        {

            Console.WriteLine("Testing nested serialization of {0}:", obj);

​

            var settings = new JsonSerializerSettings

            {

                Converters = { new EsiObjConverter<mApiResponseClass>() },

            };

​

            var json = JsonConvert.SerializeObject(new { data = new [] { obj  }}, Formatting.Indented, settings);

​

            Console.WriteLine(json);

        }

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: " + Environment.Version);

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

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

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

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​