Masuit.Tools/Masuit.Tools.AspNetCore/ModelBinder/BodyOrDefaultModelBinder.cs

using System;
using System.Text;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

namespace Masuit.Tools.AspNetCore.ModelBinder
{
    public class BodyOrDefaultModelBinder : IModelBinder
    {
        private readonly IModelBinder _bodyBinder;
        private readonly IModelBinder _complexBinder;

        public BodyOrDefaultModelBinder(IModelBinder bodyBinder, IModelBinder complexBinder)
        {
            _bodyBinder = bodyBinder;
            _complexBinder = complexBinder;
        }

        public async Task BindModelAsync(ModelBindingContext bindingContext)
        {
            var request = bindingContext.HttpContext.Request;
            request.EnableBuffering();
            var buffer = new byte[Convert.ToInt32(request.ContentLength)];
            _ = await request.Body.ReadAsync(buffer, 0, buffer.Length);
            var text = Encoding.UTF8.GetString(buffer);
            request.Body.Position = 0;

            if (bindingContext.ModelType.IsPrimitive || bindingContext.ModelType == typeof(string) || bindingContext.ModelType.IsEnum || bindingContext.ModelType == typeof(DateTime) || bindingContext.ModelType == typeof(Guid))
            {
                var parameter = bindingContext.ModelMetadata.ParameterName;
                var value = "";
                if (request.Query.ContainsKey(parameter))
                {
                    value = request.Query[parameter] + "";
                }
                else if (request.ContentType.StartsWith("application/json"))
                {
                    value = JObject.Parse(text)[parameter] + "";
                }
                else if (request.HasFormContentType)
                {
                    value = request.Form[bindingContext.ModelMetadata.ParameterName] + "";
                }

                if (value.TryConvertTo(bindingContext.ModelType, out var result))
                {
                    bindingContext.Result = ModelBindingResult.Success(result);
                }
                return;
            }

            if (request.HasFormContentType)
            {
                if (bindingContext.ModelType.IsClass)
                {
                    await DefaultBindModel(bindingContext);
                }
                else
                {
                    bindingContext.Result = ModelBindingResult.Success(request.Form[bindingContext.ModelMetadata.ParameterName].ToString().ConvertTo(bindingContext.ModelType));
                }
                return;
            }

            try
            {
                bindingContext.Result = ModelBindingResult.Success(JsonConvert.DeserializeObject(text, bindingContext.ModelType) ?? request.Query[bindingContext.ModelMetadata.ParameterName!].ToString().ConvertTo(bindingContext.ModelType));
            }
            catch
            {
                await DefaultBindModel(bindingContext);
            }
        }

        private async Task DefaultBindModel(ModelBindingContext bindingContext)
        {
            await _bodyBinder.BindModelAsync(bindingContext);

            if (bindingContext.Result.IsModelSet)
            {
                return;
            }

            bindingContext.ModelState.Clear();
            await _complexBinder.BindModelAsync(bindingContext);
        }
    }
}