Refactor Login page to use MediatR commands/queries

SecurityService.BusinessLogic/RequestHandlers/LoginRequestHandler.cs

@@ -0,0 +1,57 @@
+using MediatR;
+using Microsoft.AspNetCore.Identity;
+using SecurityService.BusinessLogic.Requests;
+using SecurityService.Database;
+using SecurityService.Models;
+using SimpleResults;
+
+namespace SecurityService.BusinessLogic.RequestHandlers;
+
+public sealed class LoginRequestHandler :
+    IRequestHandler<SecurityServiceQueries.GetExternalProvidersQuery, Result<List<ExternalProviderDetails>>>,
+    IRequestHandler<SecurityServiceCommands.LoginCommand, Result>
+{
+    private readonly SignInManager<ApplicationUser> _signInManager;
+
+    public LoginRequestHandler(SignInManager<ApplicationUser> signInManager)
+    {
+        this._signInManager = signInManager;
+    }
+
+    public async Task<Result<List<ExternalProviderDetails>>> Handle(SecurityServiceQueries.GetExternalProvidersQuery query, CancellationToken cancellationToken)
+    {
+        var providers = (await this._signInManager.GetExternalAuthenticationSchemesAsync())
+            .Select(scheme => new ExternalProviderDetails(scheme.Name, scheme.DisplayName ?? scheme.Name))
+            .OrderBy(provider => provider.DisplayName, StringComparer.OrdinalIgnoreCase)
+            .ToList();
+
+        return Result.Success(providers);
+    }
+
+    public async Task<Result> Handle(SecurityServiceCommands.LoginCommand command, CancellationToken cancellationToken)
+    {
+        var result = await this._signInManager.PasswordSignInAsync(command.Username, command.Password, command.RememberLogin, lockoutOnFailure: true);
+
+        if (result.Succeeded)
+        {
+            return Result.Success();
+        }
+
+        if (result.IsLockedOut)
+        {
+            return Result.Failure("Your account has been locked. Please try again later or contact support.");
+        }
+
+        if (result.IsNotAllowed)
+        {
+            return Result.Failure("You are not allowed to sign in. Please confirm your email address.");
+        }
+
+        if (result.RequiresTwoFactor)
+        {
+            return Result.Failure("Two-factor authentication is required.");
+        }
+
+        return Result.Failure("Invalid username or password.");
+    }
+}

SecurityService.BusinessLogic/Requests/SecurityServiceCommands.cs

@@ -67,4 +67,6 @@ public record ProcessPasswordResetConfirmationCommand(String Username,
                                                           String Token,
                                                           String Password,
                                                           String ClientId) : IRequest<Result<String>>;
+
+    public sealed record LoginCommand(string Username, string Password, bool RememberLogin) : IRequest<Result>;
 }

SecurityService.BusinessLogic/Requests/SecurityServiceQueries.cs

@@ -22,4 +22,5 @@ public sealed record GetRoleQuery(string RoleId) : IRequest<Result<RoleDetails>>
     public sealed record GetRolesQuery() : IRequest<Result<List<RoleDetails>>>;
     public sealed record GetUserQuery(string UserId) : IRequest<Result<UserDetails>>;
     public sealed record GetUsersQuery(string? UserName) : IRequest<Result<List<UserDetails>>>;
+    public sealed record GetExternalProvidersQuery() : IRequest<Result<List<ExternalProviderDetails>>>;
 }

SecurityService.Models/DetailsModels.cs

@@ -48,3 +48,5 @@ public sealed record UserDetails(
     string? FamilyName,
     IReadOnlyDictionary<string, string> Claims,
     IReadOnlyCollection<string> Roles);
+
+public sealed record ExternalProviderDetails(string Name, string DisplayName);

SecurityService.UnitTests/Pages/LoginPageModelTests.cs

@@ -1,10 +1,12 @@
+using MediatR;
 using Microsoft.AspNetCore.Http;
-using Microsoft.AspNetCore.Identity;
 using Microsoft.AspNetCore.Mvc;
 using Moq;
-using SecurityService.Database;
+using SecurityService.BusinessLogic.Requests;
+using SecurityService.Models;
 using SecurityService.UnitTests.Infrastructure;
 using Shouldly;
+using SimpleResults;
 
 namespace SecurityService.UnitTests.Pages;
 
@@ -13,9 +15,11 @@ public class LoginPageModelTests
     [Fact]
     public async Task OnPost_WhenForgotPasswordSelected_RedirectsToForgotPasswordWithReturnUrlAndClientId()
     {
-        var userManager = IdentityMocks.CreateUserManager();
-        var signInManager = IdentityMocks.CreateSignInManager(userManager);
-        var model = CreateModel(signInManager, new DefaultHttpContext());
+        var mediator = new Mock<IMediator>();
+        mediator.Setup(m => m.Send(It.IsAny<SecurityServiceQueries.GetExternalProvidersQuery>(), It.IsAny<CancellationToken>()))
+            .ReturnsAsync(Result.Success(new List<ExternalProviderDetails>()));
+
+        var model = CreateModel(mediator, new DefaultHttpContext());
         model.Input = new SecurityService.Pages.Account.Login.IndexModel.InputModel
         {
             Button = "forgotpassword",
@@ -30,16 +34,12 @@ public async Task OnPost_WhenForgotPasswordSelected_RedirectsToForgotPasswordWit
         redirect.RouteValues.ShouldNotBeNull();
         redirect.RouteValues["returnUrl"].ShouldBe("/connect/authorize?client_id=test-client-id");
         redirect.RouteValues["clientId"].ShouldBe("test-client-id");
-        signInManager.Verify(instance => instance.PasswordSignInAsync(
-            It.IsAny<string>(),
-            It.IsAny<string>(),
-            It.IsAny<bool>(),
-            It.IsAny<bool>()), Times.Never);
+        mediator.Verify(m => m.Send(It.IsAny<SecurityServiceCommands.LoginCommand>(), It.IsAny<CancellationToken>()), Times.Never);
     }
 
-    private static SecurityService.Pages.Account.Login.IndexModel CreateModel(Mock<SignInManager<ApplicationUser>> signInManager, HttpContext httpContext)
+    private static SecurityService.Pages.Account.Login.IndexModel CreateModel(Mock<IMediator> mediator, HttpContext httpContext)
     {
-        return new SecurityService.Pages.Account.Login.IndexModel(signInManager.Object)
+        return new SecurityService.Pages.Account.Login.IndexModel(mediator.Object)
         {
             PageContext = new Microsoft.AspNetCore.Mvc.RazorPages.PageContext
             {
@@ -48,3 +48,4 @@ private static SecurityService.Pages.Account.Login.IndexModel CreateModel(Mock<S
         };
     }
 }
+

SecurityService/Pages/Account/Login/Index.cshtml.cs

@@ -1,18 +1,18 @@
-using Microsoft.AspNetCore.Identity;
+using MediatR;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.RazorPages;
 using Microsoft.AspNetCore.WebUtilities;
-using SecurityService.Database;
+using SecurityService.BusinessLogic.Requests;
 
 namespace SecurityService.Pages.Account.Login;
 
 public sealed class IndexModel : PageModel
 {
-    private readonly SignInManager<ApplicationUser> _signInManager;
+    private readonly IMediator _mediator;
 
-    public IndexModel(SignInManager<ApplicationUser> signInManager)
+    public IndexModel(IMediator mediator)
     {
-        this._signInManager = signInManager;
+        this._mediator = mediator;
     }
 
     [BindProperty]
@@ -52,22 +52,22 @@ public async Task<IActionResult> OnPostAsync()
             });
         }
 
-        var result = await this._signInManager.PasswordSignInAsync(this.Input.Username, this.Input.Password, this.Input.RememberLogin, lockoutOnFailure: true);
-        if (result.Succeeded)
+        var result = await this._mediator.Send(new SecurityServiceCommands.LoginCommand(this.Input.Username, this.Input.Password, this.Input.RememberLogin));
+        if (result.IsSuccess)
         {
             return this.LocalRedirect(string.IsNullOrWhiteSpace(this.Input.ReturnUrl) ? "/" : this.Input.ReturnUrl);
         }
 
-        this.ModelState.AddModelError(string.Empty, "Invalid username or password.");
+        this.ModelState.AddModelError(string.Empty, result.Errors.FirstOrDefault() ?? result.Message ?? "Invalid username or password.");
         return this.Page();
     }
 
     private async Task LoadProvidersAsync()
     {
-        this.Providers = (await this._signInManager.GetExternalAuthenticationSchemesAsync())
-            .Select(scheme => new ExternalProviderViewModel(scheme.Name, scheme.DisplayName ?? scheme.Name))
-            .OrderBy(provider => provider.DisplayName, StringComparer.OrdinalIgnoreCase)
-            .ToArray();
+        var result = await this._mediator.Send(new SecurityServiceQueries.GetExternalProvidersQuery());
+        this.Providers = result.IsSuccess
+            ? result.Data.Select(p => new ExternalProviderViewModel(p.Name, p.DisplayName)).ToArray()
+            : Array.Empty<ExternalProviderViewModel>();
     }
 
     public sealed class InputModel
@@ -83,3 +83,4 @@ public sealed class InputModel
 
     public sealed record ExternalProviderViewModel(string Name, string DisplayName);
 }
+