DI 2

appsettings.json

{
  "PhotoService": {
    "UploadDirectory": "D:\\Uploads",
    "PublicPath": "/Uploads"
  }
}

Startup.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;

namespace DiExamples
{
    public class Startup
    {
        public IConfiguration Configuration { get; }
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }
        public void ConfigureServices(IServiceCollection services)
        {
            services.Configure<PhotoServiceOptions>(Configuration.GetSection("PhotoService"));

            services.AddSingleton<IPhotoService, PhotoService>();
        }

        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.Run(async (context) =>
            {
                var photoService = context.RequestServices.GetRequiredService<IPhotoService>();
                await context.Response.WriteAsync(photoService.Upload());
            });
        }
    }

    public interface IPhotoService
    {
        string Upload();
    }

    public class PhotoServiceOptions
    {
        public string UploadDirectory { get; set; }
        public string PublicPath { get; set; }
    }

    public class PhotoService : IPhotoService
    {
        private readonly PhotoServiceOptions _options;

        public PhotoService(IOptionsMonitor<PhotoServiceOptions> serviceOptions)
        {
            _options = serviceOptions.CurrentValue;
        }
        public string Upload()
        {
            // Do some work
            return $"Upload Done. Folder {_options.UploadDirectory} , Path {_options.PublicPath}";
        }
    }
}