NejCommon.NET/Controllers/ResponseEnricher.cs

using System.Text;
using System.Xml;
using System.Xml.Serialization;
using ClosedXML.Excel;
using Microsoft.AspNetCore.Http.HttpResults;
using Microsoft.AspNetCore.Mvc;

namespace NejCommon.Controllers;

public static class Responses
{
    public static FileStreamHttpResult RespondFileStream(this ControllerBase controller, Stream stream, string contentType, string fileName)
    {
        stream.Seek(0, SeekOrigin.Begin);

        controller.Response.Headers.Add("Content-Disposition", "inline; filename=" + fileName);
        return TypedResults.File(stream, contentType, fileName);
    }
    public static FileStreamHttpResult RespondXlsx(this ControllerBase controller, XLWorkbook file, string fileName)
    {
        var stream = new MemoryStream();
        file.SaveAs(stream);

        return RespondFileStream(controller, stream, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", fileName);
    }
    public static FileStreamHttpResult RespondXlsxTable<T>(this ControllerBase controller, IEnumerable<T> data, string name = "Data", string? sheetName = null)
    {
        if (sheetName is null)
        {
            //limit the name to 31 characters
            sheetName = name.Length > 31 ? name.Substring(0, 31) : name;
        }

        var notebook = new XLWorkbook();
        var sheet = notebook.Worksheets.Add(sheetName);
        sheet.FirstCell().InsertTable(data);

        sheet.Columns().AdjustToContents();

        return controller.RespondXlsx(notebook, name + ".xlsx");
    }

    public static FileStreamHttpResult RespondXml<T>(this ControllerBase controller, T obj, string fileName = "Data.xml")
    {
        var stream = Utils.Xml.Serialize(obj);

        return RespondFileStream(controller, stream, "text/xml", fileName);
    }
}