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 Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Serialization;    

​

    // https://stackoverflow.com/questions/29449641/deserialize-json-when-type-can-be-different#29449760

​

    public class JsonSingleOrEmptyArrayConverter<T> : JsonConverter where T : class

    {

        public override bool CanConvert(Type objectType)

        {

            return typeof(T).IsAssignableFrom(objectType);

        }

​

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

​

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

        {

            var contract = serializer.ContractResolver.ResolveContract(objectType);

            if (!(contract is Newtonsoft.Json.Serialization.JsonObjectContract || contract is Newtonsoft.Json.Serialization.JsonDictionaryContract))

            {

                throw new JsonSerializationException(string.Format("Unsupported objectType {0} at {1}.", objectType, reader.Path));

            }

​

            switch (reader.SkipComments().TokenType)

            {

                case JsonToken.StartArray:

                    {

                        int count = 0;

                        while (reader.Read())

                        {

                            switch (reader.TokenType)

                            {

                                case JsonToken.Comment:

                                    break;

                                case JsonToken.EndArray:

                                    return existingValue;

                                default:

                                    {

                                        count++;

                                        if (count > 1)

                                            throw new JsonSerializationException(string.Format("Too many objects at path {0}.", reader.Path));

                                        existingValue = existingValue ?? contract.DefaultCreator();

                                        serializer.Populate(reader, existingValue);

                                    }

                                    break;

                            }

                        }

                        // Should not come here.

                        throw new JsonSerializationException(string.Format("Unclosed array at path {0}.", reader.Path));

                    }

​

                case JsonToken.Null:

                    return null;

​

                case JsonToken.StartObject:

                    existingValue = existingValue ?? contract.DefaultCreator();

                    serializer.Populate(reader, existingValue);

                    return existingValue;

​

                default:

                    throw new InvalidOperationException("Unexpected token type " + reader.TokenType.ToString());

            }

        }

​

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

        {

            throw new NotImplementedException();

        }

    }

​

    public static partial class JsonExtensions

    {

        public static JsonReader SkipComments(this JsonReader reader)

        {

            while (reader.TokenType == JsonToken.Comment && reader.Read())

                ;

            return reader;

        }

    }

​

    // https://stackoverflow.com/questions/29449641/deserialize-json-when-type-can-be-different#29449760

    public class User

    {

        //some other fields...

        [JsonConverter(typeof(JsonSingleOrEmptyArrayConverter<Personal>))]

        public Personal personal { get; set; }

        //some other fields...

    }

​

    public class Personal

    {

        public byte political { get; set; }

        public string[] langs { get; set; }

        public string religion { get; set; }

        public string inspired_by { get; set; }

        public byte people_main { get; set; }

        public byte life_main { get; set; }

        public byte smoking { get; set; }

        public byte alcohol { get; set; }

    }

​

    public class TestClass

    {

        public static void Test()

        {

            string json0 = @"{ personal: null }";

            string json1 = @"{ personal: [] }";

            string json2 = @"{

                personal: {

                religion: 'Нет',

                smoking: 1,

                alcohol: 4

                } //when not empty.

            }";

​

            string json3 = @"{

                personal: [/* Some Comment */{

                religion: 'Нет',

                smoking: 1,

                alcohol: 4

                }/* Some Comment */] //when not empty.

            }";

​

            string json4 = @"{

                personal: [

                /* Some Comment */{

                religion: 'Нет',

                smoking: 1,

                alcohol: 4

                }/* Some Comment */,

                /* Some Comment */{

                religion: 'Нет',

                smoking: 1,

                alcohol: 4

                }/* Some Comment */,

            ] //when not empty.

            }";

​

            string json5 = @"{

                personal: [

                /* Some Comment */{

                religion: 'Нет',

                smoking: 1,

                alcohol: 4

                }";

​

            Test(json0, p => Assert.IsTrue(p == null));

            Test(json1, p => Assert.IsTrue(p == null));

            Test(json2, p => Assert.IsTrue(p != null && p.religion == "Нет"));

            Test(json3, p => Assert.IsTrue(p != null && p.religion == "Нет"));

            try

            {

                Test(json4, p => { throw new AssertionFailedException("Should have failed"); } );

            }

            catch (JsonException ex)

            {

                Console.WriteLine("Caught expected exception: " + ex.Message);

            }

​

            try

            {

                Test(json5, p => { throw new AssertionFailedException("Should have failed"); });

            }

            catch (JsonException ex)

            {

                Console.WriteLine("Caught expected exception: " + ex.Message);

            }

​

            Console.WriteLine("Done with tests.");

        }

​

        static void Test(string json, Action<Personal> validate)

        {

            var user = JsonConvert.DeserializeObject<User>(json);

            var newJson = JsonConvert.SerializeObject(user, Formatting.Indented);

            Console.WriteLine(newJson);

​

            validate(user.personal);

        }

    }

​

    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;

            }

        }

    }

​

    public class AssertionFailedException : System.Exception

    {

        public AssertionFailedException() : base() { }

​

        public AssertionFailedException(string s) : base(s) { }

    }

​

    public static class Assert

    {

        public static void IsTrue(bool value)

        {

            IsTrue(value, "failed");

        }

​

        public static void IsTrue(bool value, string message)

        {

            if (value == false)

                throw new AssertionFailedException(message ?? "failed");

        }

    }

​