namespace Refactoring.Day10.DesignByContract.Before
{
    public class MathMehods
    {
        public double Divide(int dividend, int divisor)
        {
            return dividend / divisor;
        }
    }
}

using System;

namespace Refactoring.Day10.DesignByContract.After
{
    public class MathMehods
    {
        public double Divide(int dividend, int divisor)
        {
            if (divisor == 0)
                throw new ArgumentException("divisor cannot be zero", "divisor");

            return dividend / divisor;
        }
    }
}

using System.Diagnostics.Contracts;

namespace Refactoring.Day10.DesignByContract.After
{
    public class MathMehods
    {
        public double Divide(int dividend, int divisor)
        {
            Contract.Requires(divisor != 0, "divisor cannot be zero");

            return dividend / divisor;
        }
    }
}

• Code Contracts in C#
• Code Contracts in .NET 4
• Introduction to Code Contracts

 Smart Unit Tests tries to address these impediments. It discovers all code paths in your code, synthesizes precise test input values that exercise those code paths, and then records what the output from your code was for the said inputs

    public class HomeController : Controller
    {
        public IActionResult GetFile()
        {
            return PhysicalFile(@"C:\path\file.pdf", "application/pdf");
        }

https://idpHostAddress/connect/authorize? 
client_id=imagegalleryclient 
&redirect_uri=https://clientapphostaddress/signin-oidcoidc 
&scope=openid profile 
&response_type=code id_token 
&response_mode=form_post
&nonce=63626...n2eNMxA0

namespace DNT.IDP
{
    public static class Config
    {
        public static IEnumerable<Client> GetClients()
        {
            return new List<Client>
            {
                new Client
                {
                    ClientName = "Image Gallery",
                    ClientId = "imagegalleryclient",
                    AllowedGrantTypes = GrantTypes.Hybrid,
                    RedirectUris = new List<string>
                    {
                        "https://localhost:5001/signin-oidc"
                    },
                    PostLogoutRedirectUris = new List<string>
                    {
                        "https://localhost:5001/signout-callback-oidc"
                    },
                    AllowedScopes =
                    {
                        IdentityServerConstants.StandardScopes.OpenId,
                        IdentityServerConstants.StandardScopes.Profile
                    },
                    ClientSecrets =
                    {
                        new Secret("secret".Sha256())
                    }
                }
             };
        }
    }
}

namespace ImageGallery.MvcClient.WebApp
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddAuthentication(options =>
            {
                options.DefaultScheme = "Cookies";
                options.DefaultChallengeScheme = "oidc";
            }).AddCookie("Cookies")
              .AddOpenIdConnect("oidc", options =>
              {
                  options.SignInScheme = "Cookies";
                  options.Authority = "https://localhost:6001";
                  options.ClientId = "imagegalleryclient";
                  options.ResponseType = "code id_token";
                  //options.CallbackPath = new PathString("...")
                  //options.SignedOutCallbackPath = new PathString("...")
                  options.Scope.Add("openid");
                  options.Scope.Add("profile");
                  options.SaveTokens = true;
                  options.ClientSecret = "secret";
                  options.GetClaimsFromUserInfoEndpoint = true;
              });

namespace ImageGallery.MvcClient.WebApp
{
    public class Startup
    {
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            app.UseAuthentication();

namespace ImageGallery.MvcClient.WebApp.Controllers
{
    [Authorize]
    public class GalleryController : Controller
    {
    // .... 
   
        public async Task WriteOutIdentityInformation()
        {
            var identityToken = await HttpContext.GetTokenAsync(OpenIdConnectParameterNames.IdToken);
            Debug.WriteLine($"Identity token: {identityToken}");

            foreach (var claim in User.Claims)
            {
                Debug.WriteLine($"Claim type: {claim.Type} - Claim value: {claim.Value}");
            }
        }

        public async Task<IActionResult> Index()
        {
            await WriteOutIdentityInformation();
            // ....

<div class="navbar-collapse collapse">
    <ul class="nav navbar-nav">
        <li><a asp-area="" asp-controller="Gallery" asp-action="Index">Home</a></li>
        <li><a asp-area="" asp-controller="Gallery" asp-action="AddImage">Add an image</a></li>
        @if (User.Identity.IsAuthenticated)
        {
            <li><a asp-area="" asp-controller="Gallery" asp-action="Logout">Logout</a></li>
        }
    </ul>
</div>

namespace ImageGallery.MvcClient.WebApp.Controllers
{
    [Authorize]
    public class GalleryController : Controller
    {
        public async Task Logout()
        {
            // Clears the  local cookie ("Cookies" must match the name of the scheme)
            await HttpContext.SignOutAsync("Cookies");
            await HttpContext.SignOutAsync("oidc");
        }

PostLogoutRedirectUris = new List<string>
{
     "https://localhost:5001/signout-callback-oidc"
},

options.Scope.Add("openid");
options.Scope.Add("profile");

options.GetClaimsFromUserInfoEndpoint = true;

"C:\Program Files\Git\usr\bin\openssl.exe" genrsa -out private.key 2048
"C:\Program Files\Git\usr\bin\openssl.exe" req -new -x509 -key private.key -out publickey.cer -days 1398
"C:\Program Files\Git\usr\bin\openssl.exe" pkcs12 -export -out idp.pfx -inkey private.key -in publickey.cer

private static X509Certificate2 loadCertificateFromFile(string filePath, string password)
{
    // NOTE:
    // You should check out the identity of your application pool and make sure
    // that the `Load user profile` option is turned on, otherwise the crypto susbsystem won't work.

    // For decryption the certificate must be in the certificate store. It's a limitation of how EncryptedXml works.
    using (var store = new X509Store(StoreName.My, StoreLocation.CurrentUser))
    {
      store.Open(OpenFlags.ReadWrite);
      store.Add(new X509Certificate2(filePath, password, X509KeyStorageFlags.Exportable));
    }

    return new X509Certificate2(
            filePath,
            password,
            keyStorageFlags: X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.PersistKeySet
                             | X509KeyStorageFlags.Exportable);
}

services
   .AddDataProtection()
   .SetDefaultKeyLifetime(...)
   .SetApplicationName(...)
   .ProtectKeysWithCertificate(loadCertificateFromFile("path ...", "123"));

namespace DNT.IDP.DomainClasses
{
    public class User
    {
        [Key]
        [MaxLength(50)]       
        public string SubjectId { get; set; }
    
        [MaxLength(100)]
        [Required]
        public string Username { get; set; }

        [MaxLength(100)]
        public string Password { get; set; }

        [Required]
        public bool IsActive { get; set; }

        public ICollection<UserClaim> UserClaims { get; set; }

        public ICollection<UserLogin> UserLogins { get; set; }
    }
}

namespace DNT.IDP.DomainClasses
{
    public class UserClaim
    {         
        public int Id { get; set; }

        [MaxLength(50)]
        [Required]
        public string SubjectId { get; set; }
        
        public User User { get; set; }

        [Required]
        [MaxLength(250)]
        public string ClaimType { get; set; }

        [Required]
        [MaxLength(250)]
        public string ClaimValue { get; set; }
    }
}

namespace DNT.IDP.DomainClasses
{
    public class UserLogin
    {
        public int Id { get; set; }

        [MaxLength(50)]
        [Required]
        public string SubjectId { get; set; }
        
        public User User { get; set; }

        [Required]
        [MaxLength(250)]
        public string LoginProvider { get; set; }

        [Required]
        [MaxLength(250)]
        public string ProviderKey { get; set; }
    }
}

    public interface IUsersService
    {
        Task<bool> AreUserCredentialsValidAsync(string username, string password);
        Task<User> GetUserByEmailAsync(string email);
        Task<User> GetUserByProviderAsync(string loginProvider, string providerKey);
        Task<User> GetUserBySubjectIdAsync(string subjectId);
        Task<User> GetUserByUsernameAsync(string username);
        Task<IEnumerable<UserClaim>> GetUserClaimsBySubjectIdAsync(string subjectId);
        Task<IEnumerable<UserLogin>> GetUserLoginsBySubjectIdAsync(string subjectId);
        Task<bool> IsUserActiveAsync(string subjectId);
        Task AddUserAsync(User user);
        Task AddUserLoginAsync(string subjectId, string loginProvider, string providerKey);
        Task AddUserClaimAsync(string subjectId, string claimType, string claimValue);
    }

@using DNT.IDP.Controllers.Account;
@using DNT.IDP.Controllers.Consent;
@using DNT.IDP.Controllers.Grants;
@using DNT.IDP.Controllers.Home;
@using DNT.IDP.Controllers.Diagnostics;
@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers

 public static class IdentityServerBuilderExtensions
 {
        public static IIdentityServerBuilder AddTestUsers(this IIdentityServerBuilder builder, List<TestUser> users)
        {
            builder.Services.AddSingleton(new TestUserStore(users));
            builder.AddProfileService<TestUserProfileService>();
            builder.AddResourceOwnerValidator<TestUserResourceOwnerPasswordValidator>();

            return builder;
        }
}

using DNT.IDP.Services;
using Microsoft.Extensions.DependencyInjection;

namespace DNT.IDP
{
    public static class IdentityServerBuilderExtensions
    {
        public static IIdentityServerBuilder AddCustomUserStore(this IIdentityServerBuilder builder)
        {
            // builder.Services.AddScoped<IUsersService, UsersService>();
            builder.AddProfileService<CustomUserProfileService>();
            return builder;
        }
    }
}

namespace DNT.IDP.Services
{
    public class CustomUserProfileService : IProfileService
    {
        private readonly IUsersService _usersService;

        public CustomUserProfileService(IUsersService usersService)
        {
            _usersService = usersService;
        }

        public async Task GetProfileDataAsync(ProfileDataRequestContext context)
        {
            var subjectId = context.Subject.GetSubjectId();
            var claimsForUser = await _usersService.GetUserClaimsBySubjectIdAsync(subjectId);
            context.IssuedClaims = claimsForUser.Select(c => new Claim(c.ClaimType, c.ClaimValue)).ToList();
        }

        public async Task IsActiveAsync(IsActiveContext context)
        {
            var subjectId = context.Subject.GetSubjectId();
            context.IsActive = await _usersService.IsUserActiveAsync(subjectId);
        }
    }
}

namespace DNT.IDP
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddIdentityServer()
             .AddDeveloperSigningCredential()
             .AddCustomUserStore()
             .AddInMemoryIdentityResources(Config.GetIdentityResources())
             .AddInMemoryApiResources(Config.GetApiResources())
             .AddInMemoryClients(Config.GetClients());

        public AccountController(
            IIdentityServerInteractionService interaction,
            IClientStore clientStore,
            IAuthenticationSchemeProvider schemeProvider,
            IEventService events,
            TestUserStore users = null)
        {
            _users = users ?? new TestUserStore(TestUsers.Users);

            _interaction = interaction;
            _clientStore = clientStore;
            _schemeProvider = schemeProvider;
            _events = events;
        }

        private readonly TestUserStore _users;
        private readonly IUsersService _usersService;
        public AccountController(
    // ...
            IUsersService usersService)
        {
            _usersService = usersService;
    // ...
        }

        public async Task<IActionResult> Login(LoginInputModel model, string button)
        {
    //...
            if (ModelState.IsValid)
            {
                if (await _usersService.AreUserCredentialsValidAsync(model.Username, model.Password))
                {
                    var user = await _usersService.GetUserByUsernameAsync(model.Username);

    public class RegisterUserViewModel
    {
        // credentials       
        [MaxLength(100)]
        public string Username { get; set; }

        [MaxLength(100)]
        public string Password { get; set; }

    public class RegisterUserViewModel
    {
   // ...

        // claims 
        [Required]
        [MaxLength(100)]
        public string Firstname { get; set; }

        [Required]
        [MaxLength(100)]
        public string Lastname { get; set; }

        [Required]
        [MaxLength(150)]
        public string Email { get; set; }

        [Required]
        [MaxLength(200)]
        public string Address { get; set; }

        [Required]
        [MaxLength(2)]
        public string Country { get; set; }

varuserToCreate=newUser
{
  Password=model.Password.GetSha256Hash(),
  Username=model.Username,
  IsActive=true
};
userToCreate.UserClaims.Add(newUserClaim("country",model.Country));
userToCreate.UserClaims.Add(newUserClaim("address",model.Address));
userToCreate.UserClaims.Add(newUserClaim("given_name",model.Firstname));
userToCreate.UserClaims.Add(newUserClaim("family_name",model.Lastname));
userToCreate.UserClaims.Add(newUserClaim("email",model.Email));
userToCreate.UserClaims.Add(newUserClaim("subscriptionlevel","FreeUser"));

Mini Course #1 Clean Architecture + CQRS - YouTube

00:00:00 - Intro
00:01:10 - Why do we record this course?
00:04:39 - Layered architecture: Why I don't like it anymore?
00:27:27 - Clean architecture
00:38:16 - Course prerequisites (still can't pronounce it correctly)
00:42:30 - What do we build?
00:45:18 - *Domain Layer*
00:49:57 - Entity
01:00:20 - Primitive obsession code smell
01:03:20 - Value Object
01:10:54 - Custom exceptions
01:33:25 - Domain model validation
01:38:55 - Aggregate
01:50:50 - Domain event
02:14:30 - Factory
02:28:50 - Policy
02:43:50 - Repository
02:48:55 - Domain Layer: Summary
02:56:45 - CQS: Command Query Separation
03:07:46 - CQRS: Command Query Responsibility Segregation
03:29:48 - *Application Layer*
03:30:25 - Command/Command Handler/Command Dispatcher definitions
03:40:45 - Automatic command handlers registration
03:44:12 - Application & Domain registration
03:50:52 - Command
03:55:31 - Command Handler
04:01:11 - Where to put methods related to reading?
04:07:00 - Read Service
04:14:14 - Weather Service
04:28:25 - Overview of the other commands & command handlers
04:34:35 - Query/Query Handler/Query Dispatcher definitions
04:44:37 - Automatic query handlers registration (BONUS: example of copy/paste pattern)
04:52:50 - How to tackle reading on Query side?
05:06:30 - *Infrastructure Layer*
05:07:56 - Configuration of Entity Framework Core
05:15:15 - Read Models
05:19:05 - ReadDbContext & WriteDbContext
05:24:13 - EF Entity Configuration
05:42:37 - DbContexts registration
05:55:51 - Query Handlers
06:12:18 - Repository implementation on top of EF Core
06:16:45 - Read Service implementation on top of EF Core
06:19:00 - Dummy Weather Service implementation
06:23:20 - EF Migration
06:29:50 - Applying EF migrations automatically
06:39:38 - *Presentation Layer*
06:41:35 - Controller
06:50:43 - How to return ID of resource in CQRS approach?
07:00:02 - Testing API
07:09:29 - *Cross Cutting Concerns*
07:09:30 - Error Handling
07:20:49 - Logging
07:34:57 - *Unit Testing*
07:42:34 - Unit Test on Domain Layer
08:09:45 - Unit Test on Application Layer
08:34:00 - Summary