ASP.NET Web API : data object with JsonPropertyName attribute expect the payload to be the JsonPropertyName and i need the reular propertyName instead

Question

This is the API method:

[Authorize]
[HttpPost("pa/questionnaire")]
[ProducesResponseType(200, Type = typeof(ApiResponse))]
[ProducesResponseType(500, Type = typeof(ApiResponse))]
public async Task<IActionResult> FillPA([FromBody] QuestionnaireData data)

This is the QuestionnaireData class:

public class QuestionnaireData
{
    public string Id { get; set; }
    public DateTime? SignedDate { get; set; }
    public Questionnaire Questionnaire { get; set; }
}

public class Questionnaire
{   
    [JsonPropertyName("patient_signature_date")]
    public DateTime? PatientSignatureDate { get; set; }

    [JsonPropertyName("patient_dob")]
    public DateTime? PatientDob { get; set; }
    [JsonPropertyName("patient_email")]
    public string PatientEmail { get; set; }
    
    [JsonPropertyName("patient_gender")] 
    public string PatientGender { get; set; }

    [JsonPropertyName("patient_cell_phone")]
    public string PatientCellPhone { get; set; }

    [JsonPropertyName("patient_address")]
    public string PatientAddress { get; set; }

    [JsonPropertyName("patient_city")]
    public string PatientCity { get; set; }
}

I need to use this payload (with original properties name):

{
    "Id": "234567",
    "signedDate": "2024-09-30T00:00:00",
    "questionnaire": {
                         "patientEmail": "september18@yopmail.com",
                         "patientCellPhone": "(817)-123-4567",
                         "patientDob": "2001-02-02",
                         "patientGender": "female",
                         "patientAddress": "96 FOREST ST",
                         "patientCity":"BOSTON"
                     }
}

But instead it only works with the json property name :

{
    "Id": "a5UU90000002VEEMA2",
    "signedDate": "2024-09-30T00:00:00",
    "Questionnaire": {
         "patient_dob": "2024-09-30T08:16:06.509Z",
         "patient_email": "string",
         "patient_gender": "string",
         "patient_cell_phone": "string",
         "patient_address": "string",
         "patient_city": "string"
    }
}

I need the attribute for future use (in order - to convert the object values to key value pairs and post it to another API), but not for the payload naming,

Does anyone have any idea?

Answer 1

I create a sample and make it works, here is my detailed steps.

The structure of project

Test Code

1. CaseInsensitiveConverter.cs

using System.Reflection;
using System.Text.Json;
using System.Text.Json.Serialization;
using System.Text.RegularExpressions;

namespace WebApplication1
{
    public class CaseInsensitiveConverter<T> : JsonConverter<T> where T : new()
    {
        public override T Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
        {
            if (reader.TokenType != JsonTokenType.StartObject)
                throw new JsonException();

            var instance = new T();
            var properties = typeToConvert.GetProperties(BindingFlags.Instance | BindingFlags.Public);

            while (reader.Read())
            {
                if (reader.TokenType == JsonTokenType.EndObject)
                    return instance;

                if (reader.TokenType != JsonTokenType.PropertyName)
                    throw new JsonException();

                var propertyName = reader.GetString();
                var property = properties.FirstOrDefault(p =>
                    string.Equals(p.Name, propertyName, StringComparison.OrdinalIgnoreCase) ||
                    string.Equals(ToSnakeCase(p.Name), propertyName, StringComparison.OrdinalIgnoreCase));

                if (property == null)
                {
                    reader.Skip();
                    continue;
                }

                reader.Read();

                var value = JsonSerializer.Deserialize(ref reader, property.PropertyType, options);
                property.SetValue(instance, value);
            }

            return instance;
        }

        public override void Write(Utf8JsonWriter writer, T value, JsonSerializerOptions options)
        {
            JsonSerializer.Serialize(writer, value, options);
        }

        private string ToSnakeCase(string input)
        {
            return Regex.Replace(input, "([a-z0-9])([A-Z])", "$1_$2").ToLower();
        }
    }
}

2. Use it in model.

using Microsoft.AspNetCore.Mvc;
using System.Text.Json.Serialization;

namespace WebApplication1.Models
{
    public class QuestionnaireData
    {
        public string Id { get; set; }
        public DateTime? SignedDate { get; set; }
        [JsonConverter(typeof(CaseInsensitiveConverter<Questionnaire>))]
        public Questionnaire Questionnaire { get; set; }
    }

    public class Questionnaire
    {
        [JsonPropertyName("patient_signature_date")]
        public DateTime? PatientSignatureDate { get; set; }

        [JsonPropertyName("patient_dob")]
        public DateTime? PatientDob { get; set; }
        [JsonPropertyName("patient_email")]
        public string PatientEmail { get; set; }

        [JsonPropertyName("patient_gender")]
        public string PatientGender { get; set; }

        [JsonPropertyName("patient_cell_phone")]
        public string PatientCellPhone { get; set; }

        [JsonPropertyName("patient_address")]
        public string PatientAddress { get; set; }

        [JsonPropertyName("patient_city")]
        public string PatientCity { get; set; }
    }
}

3. Register it (Use System.Text.Json, not Newtonsoft)

builder.Services.AddControllers().AddJsonOptions(options =>
{
    options.JsonSerializerOptions.Converters.Add(new CaseInsensitiveConverter<Questionnaire>());
    options.JsonSerializerOptions.PropertyNameCaseInsensitive = true;
});

4. Test Result

Use default one.

USE BELOW PAYLOAD.

{
    "Id": "234567",
    "signedDate": "2024-09-30T00:00:00",
    "questionnaire": {
                         "patientEmail": "september18@yopmail.com",
                         "patientCellPhone": "(817)-123-4567",
                         "patientDob": "2001-02-02",
                         "patientGender": "female",
                         "patientAddress": "96 FOREST ST",
                         "patientCity":"BOSTON"
                     }
}