OD.WebApplication/OD.WebApplication/Controllers/HomeController.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using AutoMapper;
using CsvHelper;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using OD.WebApplication.Models;

namespace OD.WebApplication.Controllers
{
    public class HomeController : Controller
    {
        private readonly ILogger<HomeController> _logger;
        private readonly IMapper _mapper;

        public HomeController(ILogger<HomeController> logger, IMapper mapper)
        {
            _logger = logger;
            _mapper = mapper;
        }

        public IActionResult Index()
        {
            return View();
        }

        [HttpPost]
        [ValidateAntiForgeryToken]
        public IActionResult UploadCSV(HomeViewModel model)
        {
            try  
            {  
                if (ModelState.IsValid)
                {
                    using var reader = new StreamReader(model.FileAttach.OpenReadStream());
                    using var csvReader = new CsvReader(reader, CultureInfo.GetCultureInfo("es-ES"));
                    csvReader.Configuration.BadDataFound = null;
                    csvReader.Configuration.HeaderValidated = null;
                    csvReader.Configuration.MissingFieldFound = null;
                    csvReader.Configuration.Delimiter = ";";
                    var originDto = new List<OriginDataModel>();
                    csvReader.Read();
                    csvReader.ReadHeader();
                    while (csvReader.Read())
                    {
                        var record = new OriginDataModel
                        {
                            Id = csvReader.GetField("ID"),
                            Categories = csvReader.GetField<string>("Categorías"),
                            Manufacturer = csvReader.GetField<string>("Fabricante"),
                            PriceListingWithoutVAT = decimal.Parse(csvReader.GetField("Precio tiendas sin IVA")),
                            PricePublicWithoutVAT = decimal.Parse(csvReader.GetField("PVP sin IVA")),
                            PriceRecommendedWithoutVAT = decimal.Parse(csvReader.GetField("PVR sin IVA")),
                            Stock = decimal.Parse(csvReader.GetField("Stock")),
                            Volume = float.Parse(csvReader.GetField("Volumen")),
                            Name = csvReader.GetField("Nombre"),
                            LongDesc = csvReader.GetField("Descripción larga"),
                            ShortDesc = csvReader.GetField("Descripción breve"),
                            ImageUrls = csvReader.GetField("Imagen"),
                            Ean13 = csvReader.GetField("EAN13"),
                            Sda = csvReader.GetField("SDA")
                        };
                        originDto.Add(record);
                    }
                    
                    var destinationDto = _mapper.Map<List<OriginDataModel>, List<DestinationDataModel>>(originDto);
                    
                    var ms = new MemoryStream();
                    var sw = new StreamWriter(ms);
                    using var csvWriter = new CsvWriter(sw, CultureInfo.GetCultureInfo("es-ES"));
                    csvWriter.Configuration.Delimiter = ",";
                    csvWriter.WriteRecords(destinationDto);
                    sw.Flush();
                    ms.Position = 0;
                    return File(ms.ToArray(), "text/csv", "result.csv");

                }  
            }  
            catch (Exception ex)
            {
                _logger.LogError(ex, "Attempted to perform an invalid conversion");
                return new ErrorMessageResult(new ErrorResult { Exception = ex });
            }
            
            return RedirectToAction("Index");
        }

        [ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)]
        public IActionResult Error()
        {
            return View(new ErrorViewModel {RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier});
        }
    }
}