laatzen/LaaProductionWeb/LaaProductionWeb/App_Infrastructure/ControllersExtensions.cs

namespace LaaProductionWeb.App_Infrastructure
{
    using Microsoft.Extensions.DependencyInjection;

    using System;
    using System.Linq;
    using System.Security.Claims;
    using System.Security.Principal;
    using System.Web.Mvc;

    /// <summary>
    /// Static class with extension methods that run on controller contexts.
    /// </summary>
    public static class ControllersExtensions
    {
        /// <summary>
        /// Adds controllers of type <see cref="IController"/> loaded by reflection from the current assembly to the <see cref="IServiceCollection"/>.
        /// On this way all required services are loaded into the controller constructors.
        /// </summary>
        /// <param name="services"><see cref="IServiceCollection"/> provided from the extension method.</param>
        /// <returns>The same <see cref="IServiceCollection"/> with added services.</returns>
        public static IServiceCollection AddControllers(this IServiceCollection services)
        {
            var controllersMap = typeof(ControllersExtensions)
                .Assembly
                .GetTypes()
                .Where(x => !x.IsAbstract && typeof(IController).IsAssignableFrom(x))
                .Select(x => new
                {
                    x.Name,
                    Path = x.FullName
                        .Replace("LaaProductionWeb.Controllers.", string.Empty)
                        .Replace(x.Name, string.Empty)
                })
                .GroupBy(x => x.Path)
                .ToList();

            var controllers = typeof(ControllersExtensions)
                .Assembly
                .GetTypes()
                .Where(x => !x.IsAbstract && typeof(IController).IsAssignableFrom(x));

            foreach (var controller in controllers)
            {
                services.AddTransient(controller);
            }

            return services;
        }

        public static IServiceProvider BuildControllerFactory(this IServiceProvider serviceProvider)
        {
            var controllerFactory = new ControllerFactory(serviceProvider);

            ControllerBuilder.Current.SetControllerFactory(controllerFactory);

            return serviceProvider;
        }

        public static string ClaimName(this IPrincipal principal)
        {
            if (principal is ClaimsPrincipal claimsPrincipal)
            {
                return claimsPrincipal
                    .FindAll(ClaimTypes.Name)
                    .LastOrDefault()?.Value;
            }

            return "<unknown>";
        }
    }
}