Startup.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using HR_Server.Configuration;
using HR_Server.Contexts;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace HR_Server
{
    public class Startup
    {
        public IConfiguration Configuration { get; }

        public Startup(IConfiguration configuration)
        {
            //var builder = new ConfigurationBuilder()
            //    .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
            //    .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
            //.AddEnvironmentVariables();

            ////if (env.IsDevelopment())
            ////{
            //    builder.AddUserSecrets<Startup>();
            ////}

            Configuration = configuration;
        }

        // This method gets called by the runtime. Use this method to add services to the container.
        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
        public void ConfigureServices(IServiceCollection services)
        {
            StorageConfiguration storageConfig = Configuration.GetSection("StorageConfiguration").Get<StorageConfiguration>();
            services.AddSingleton<StorageConfiguration>(storageConfig);
            services.AddEntityFrameworkSqlServer();
            services.AddDbContextPool<HrDbContext>((serviceProvider, optionsBuilder) =>
                {
                    optionsBuilder.UseSqlServer(storageConfig.Database);
                    optionsBuilder.UseInternalServiceProvider(serviceProvider);
                });

            services.AddCors(o => o.AddPolicy("AllowOrigin", builder =>
            {
                builder
                    .AllowAnyOrigin()
                    .AllowAnyMethod()
                    .AllowAnyHeader();
            }));

            services.AddControllers(); // Mvc((MvcOptions) => MvcOptions.EnableEndpointRouting = true);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            //if (env.IsDevelopment())
            //{
            //    app.UseDeveloperExceptionPage();
            //}

            //app.UseRouting();
            //app.UseMvc();

            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseHttpsRedirection();

            app.UseRouting();
            app.UseCors("AllowOrigin");
            //app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }
}