Umbraco-CMS/src/Umbraco.Web.Common/Security/ConfigureKestrelServerOptions.cs

using Microsoft.AspNetCore.Server.Kestrel.Core;
using Microsoft.Extensions.Options;
using Umbraco.Cms.Core.Configuration.Models;

namespace Umbraco.Cms.Web.Common.Security;

public class ConfigureKestrelServerOptions : IConfigureOptions<KestrelServerOptions>
{
    private readonly IOptions<RuntimeSettings> _runtimeSettings;

    public ConfigureKestrelServerOptions(IOptions<RuntimeSettings> runtimeSettings) =>
        _runtimeSettings = runtimeSettings;

    public void Configure(KestrelServerOptions options) =>

        // convert from KB to bytes, 52428800 bytes (50 MB) is the same as in the IIS settings
        options.Limits.MaxRequestBodySize = _runtimeSettings.Value.MaxRequestLength.HasValue
            ? _runtimeSettings.Value.MaxRequestLength.Value * 1024
            : 52428800;
}